<PAGE>   1
                                                                    EXHIBIT 4.26



                                  AMVESCAP INC.

                                 as Corporation



                                       and



                            CIBC MELLON TRUST COMPANY

                                   as Trustee



                                       and



                                  AMVESCAP PLC

                                  as Guarantor






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                                    INDENTURE
                     AMVESCAP EQUITY SUBORDINATED DEBENTURES

                                 August 1, 2000


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<PAGE>   2

                                TABLE OF CONTENTS


<TABLE>
<S>                   <C>                                                                                  <C>
                                                   ARTICLE 1
                                                 INTERPRETATION

Section 1.1           Definitions............................................................................1
Section 1.2           Meaning of "outstanding" for Certain Purposes..........................................8
Section 1.3           Acts of Holders........................................................................8
Section 1.4           Interpretation not Affected by Headings, etc..........................................10
Section 1.5           Applicable Law........................................................................10
Section 1.6           Invalidity Provisions.................................................................10
Section 1.7           Language..............................................................................10
Section 1.8           Successors and Assigns................................................................10
Section 1.9           Benefits of Indenture.................................................................10

                                                   ARTICLE 2
                                                 THE DEBENTURES

Section 2.1           Limit of Issue and Designation of Debentures..........................................11
Section 2.2           Form and Terms of Debentures..........................................................11
Section 2.3           Interest..............................................................................11
Section 2.4           Prescription..........................................................................12
Section 2.5           Issue of Debentures...................................................................12
Section 2.6           Concerning Interest...................................................................13
Section 2.7           Execution of Debentures...............................................................13
Section 2.8           Certification by the Trustee..........................................................13
Section 2.9           Registration of Debentures............................................................14
Section 2.10          Person Entitled to Payment............................................................15
Section 2.11          Replacement of Debentures.............................................................16
Section 2.12          Exchange of Debentures................................................................16
Section 2.13          Register Open for Inspection..........................................................17
Section 2.14          Payment of Interest and Principal.....................................................17
Section 2.15          Rank and Subordination................................................................17
Section 2.16          Notice to Debentureholders............................................................18
Section 2.17          Notice to the Trustee.................................................................18
Section 2.18          Notice to the Corporation and to the Guarantor........................................19
Section 2.19          Change in Address.....................................................................19
Section 2.20          Mail Service Interruption.............................................................19

                                                   ARTICLE 3
                                     REDEMPTION, PURCHASE AND CANCELLATION

Section 3.1           Redemption of Debentures..............................................................19
Section 3.2           Places of Payment.....................................................................20
</TABLE>



<PAGE>   3

<TABLE>
<S>                   <C>                                                                                  <C>
Section 3.3           Notice of Redemption..................................................................20
Section 3.4           Debentures Due on Redemption Date.....................................................20
Section 3.5           Deposit of Redemption Monies..........................................................21
Section 3.6           Right to Repay Redemption Amount in Exchangeable Shares...............................21
Section 3.7           Failure to Surrender Debentures Called for Redemption.................................23
Section 3.8           Purchase of Debentures................................................................24
Section 3.9           Cancellation of Purchased Debentures..................................................24

                                                   ARTICLE 4
                                      CONVERSION AND SHARE REPAYMENT RIGHT

Section 4.1           Conversion Right......................................................................24
Section 4.2           Right to Pay Conversion Value in Cash in Lieu of Conversion...........................26
Section 4.3           Right to Repay Principal Amount in Exchangeable  Shares on Maturity...................27
Section 4.4           Completion of Conversion..............................................................30
Section 4.5           Fractional Shares.....................................................................31
Section 4.6           Relating to the Issue of Exchangeable Shares..........................................31
Section 4.7           Taxes and Charges on the Issue of Exchangeable Shares.................................32

                                                   ARTICLE 5
                                                  ADJUSTMENTS

Section 5.1           Adjustment Upon Subdivision or Consolidation..........................................32
Section 5.2           Reorganization Event..................................................................32
Section 5.3           Adjustments as a Result of Certain Distributions and Extraordinary Cash Dividends.....33
Section 5.4           Discretionary Adjustment..............................................................34
Section 5.5           Changes Affecting Exchangeable Shares.................................................34
Section 5.6           Rules Applicable to Adjustments.......................................................35
Section 5.7           Notice of Special Events..............................................................35

                                                   ARTICLE 6
                                          SUBORDINATION OF DEBENTURES

Section 6.1           Agreement to Subordinate..............................................................36
Section 6.2           Distribution on Insolvency or Winding-up..............................................36
Section 6.3           Subrogation of Debentures.............................................................38
Section 6.4           No Payment to Debentureholders if Event of Default under the Senior Liabilities.......38
Section 6.5           Authorization of Debentureholders to Trustee to Effect Subordination..................39
Section 6.6           Knowledge of Trustee..................................................................39
Section 6.7           Trustee May Hold Senior Liabilities...................................................40
Section 6.8           Rights of Holders of Senior Liabilities Not Impaired..................................40
</TABLE>



<PAGE>   4

<TABLE>
<S>                   <C>                                                                                  <C>
Section 6.9           Altering the Senior Liabilities.......................................................40
Section 6.10          Additional Indebtedness...............................................................40
Section 6.11          Right of Debentureholder to Convert Not Impaired......................................40

                                                   ARTICLE 7
                                             GUARANTEE OF AMVESCAP

Section 7.1           Guarantee for Benefit of All Debentureholders.........................................40
Section 7.2           Guarantee of Principal, Interest and Other Amounts....................................41
Section 7.3           The Guarantor's Liability on Discharge of the Corporation.............................41
Section 7.4           Liability of the Guarantor............................................................42
Section 7.5           Subrogation...........................................................................43
Section 7.6           Waiver................................................................................44
Section 7.7           Waiver of Default.....................................................................44
Section 7.8           Acknowledgement.......................................................................44
Section 7.9           Notice to Guarantor...................................................................44
Section 7.10          No Set-Off Rights.....................................................................44

                                                   ARTICLE 8
                                 COVENANTS OF THE CORPORATION AND THE GUARANTOR

Section 8.1           Covenants of the Corporation..........................................................44
Section 8.2           Trustee to Give Notice of Event of Default............................................46
Section 8.3           Performance of Covenants by Trustee...................................................46
Section 8.4           Covenant of the Guarantor.............................................................46

                                                   ARTICLE 9
                                            DEFAULT AND ENFORCEMENT

Section 9.1           Events of Default.....................................................................47
Section 9.2           Waiver................................................................................48
Section 9.3           Waiver of Default or Breach...........................................................49
Section 9.4           Other Remedies........................................................................49
Section 9.5           Application of Money Collected........................................................49
Section 9.6           Control by Holders....................................................................50
Section 9.7           Limitation on Suits...................................................................50
Section 9.8           Rights of Holders To Receive Payment..................................................51
Section 9.9           Collection Suit by Trustee............................................................51
Section 9.10          Trustee May File Proofs of Claim......................................................51
Section 9.11          Undertaking for Costs.................................................................51
Section 9.12          Delay or Omission Not Waiver..........................................................52
Section 9.13          Remedies Cumulative...................................................................52
Section 9.14          Judgment Against the Corporation and/or the Guarantor.................................52
Section 9.15          Distribution of Proceeds..............................................................52
Section 9.16          Immunity of Shareholders, etc.........................................................53
Section 9.17          Trustee Appointed Attorney............................................................53
</TABLE>



<PAGE>   5

<TABLE>
<S>                   <C>                                                                                  <C>
                                                   ARTICLE 10
                                           SATISFACTION AND DISCHARGE

Section 10.1          Cancellation and Destruction..........................................................53
Section 10.2          Non-Presentation of Debentures........................................................54
Section 10.3          Repayment of Unclaimed Moneys or Exchangeable Shares to Corporation...................54
Section 10.4          Release from Covenants................................................................54

                                                   ARTICLE 11
                       MERGER, AMALGAMATION, CONSOLIDATION, CONVEYANCE, TRANSFER OR LEASE

Section 11.1          Amalgamation and Consolidation of Corporation and Conveyances Permitted Subject to
                      Certain Conditions....................................................................55
Section 11.2          Officers' Certificate and Opinion of Counsel..........................................55
Section 11.3          Vesting of Powers in Successor........................................................56
Section 11.4          Execution of Supplemental Indenture...................................................56

                                                   ARTICLE 12
                                          MEETINGS OF DEBENTUREHOLDERS

Section 12.1          Purposes for Which Meetings May be Called.............................................56
Section 12.2          Call, Notice and Place of Meetings....................................................56
Section 12.3          Persons Entitled to Vote at Meetings..................................................57
Section 12.4          Quorum; Action........................................................................57
Section 12.5          Determination of Voting Rights; Chairman; Conduct and Adjournment of Meetings.........58
Section 12.6          Counting Votes and Recording Action of Meetings.......................................58

                                                   ARTICLE 13
                                            SUPPLEMENTAL INDENTURES

Section 13.1          Supplemental Indentures Without Consent of Holders....................................59
Section 13.2          Supplemental Indentures with Consent of Holders.......................................60
Section 13.3          Execution of Supplemental Indentures..................................................61
Section 13.4          Effect of Supplemental Indentures.....................................................62

                                                   ARTICLE 14
                                             CONCERNING THE TRUSTEE

Section 14.1          Duties of Trustee.....................................................................62
Section 14.2          Rights of Trustee.....................................................................63
Section 14.3          Documents, Moneys, etc., Held by Trustee..............................................65
Section 14.4          Individual Rights of Trustee..........................................................66
</TABLE>



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<TABLE>
<S>                   <C>                                                                                  <C>
Section 14.5          Trustee's Disclaimer..................................................................66
Section 14.6          Discretion of Trustee.................................................................66
Section 14.7          Compensation and Indemnity............................................................67
Section 14.8          Replacement of Trustee................................................................68
Section 14.9          Successor Trustee by Merger, etc......................................................69
Section 14.10         Eligibility; Disqualification.........................................................69
Section 14.11         Acceptance of Trust...................................................................69
Section 14.12         Additional Evidence...................................................................69
Section 14.13         Deposit of Debentures.................................................................70
</TABLE>



<PAGE>   7
                                      -1-

                                   INDENTURE

         This Indenture dated August 1, 2000, among AMVESCAP INC. (the
"CORPORATION"), CIBC MELLON TRUST COMPANY (the "TRUSTEE") and AMVESCAP PLC (the
"GUARANTOR").

         RECITALS:

         (a)      The Corporation is a wholly-owned subsidiary of the Guarantor
                  and has authorized the execution and delivery of this
                  Indenture to provide for the creation and issuance of the
                  Debentures to be issued under this Indenture and the allotment
                  and issue of the Exchangeable Shares that may be issued upon
                  conversion, redemption or maturity of the Debentures as herein
                  provided;

         (b)      All corporate proceedings necessary to make this Indenture a
                  valid agreement of the Corporation and the Guarantor have been
                  done; and

         (c)      The foregoing recitals are made as representations and
                  statements of fact by the Corporation and the Guarantor and
                  not by the Trustee.

         In consideration of the foregoing and the mutual agreements contained
herein (the receipt and adequacy of which are acknowledged), the parties agree
as follows:

                                    ARTICLE 1
                                 INTERPRETATION

SECTION 1.1 DEFINITIONS.

(1)      In this Indenture and in the Debentures, unless there is something in
         the subject matter or context inconsistent therewith or unless
         otherwise expressly provided:

         "ACT" when used with respect to any Debentureholder has the meaning
         specified in Section 1.3(1).

         "AFFILIATE" has the meaning attributed thereto in the Securities Act
         (Ontario), as amended.

         "AMVESCAP ORDINARY SHARES" means the ordinary shares in the capital of
         the Guarantor.

         "AMVESCAP SHARE RATE" means 41.3286328902, subject to adjustment from
         time to time pursuant to Article 5.

         "AMVESCAP SHARE VALUE" means, as at any date, the amount equal to the
         AMVESCAP Share Rate multiplied by the Current Market Price as at such
         date.


<PAGE>   8
                                      -2-


         "APPLICABLE SECURITIES LEGISLATION" means applicable securities laws in
         each of the Provinces of Canada.

         "AUTHORIZED INVESTMENTS" has the meaning attributed thereto in Section
         14.3.

         "BOARD RESOLUTION" means a copy of a resolution certified by an officer
         of the Corporation to have been duly adopted by the Board of Directors
         and to be in full force and effect on the date of such certification.

         "BUSINESS DAY" means any day on which commercial banks are generally
         open for business in Toronto, Ontario and London, England, other than a
         Saturday, a Sunday or a day observed as a holiday in Toronto, Ontario
         or in London, England under applicable laws.

         "CANADIAN DOLLAR EQUIVALENT" means in respect of an amount expressed in
         a currency other than Canadian dollars (the "FOREIGN CURRENCY AMOUNT")
         at any date the product obtained by multiplying:

         (a)      the Foreign Currency Amount; by

         (b)      the noon spot exchange rate on such date for such foreign
                  currency expressed in Canadian dollars as reported by the Bank
                  of Canada or, in the event such spot exchange rate is not
                  available, such spot exchange rate on such date for such
                  foreign currency expressed in Canadian dollars as may be
                  deemed by the board of directors of the Guarantor to be
                  appropriate for such purpose.

         "CAPITAL REORGANIZATION" has the meaning attributed thereto in Section
         5.5.

         "CONVERSION DATE" means a date chosen by a Debentureholder pursuant to
         Section 4.1 for conversion of Debentures into Exchangeable Shares.

         "CONVERSION NOTICE" has the meaning attributed thereto in Section
         4.1(2).

         "CONVERSION NUMBER", as of any date, means the number obtained when (i)
         the Conversion Value as of such date is divided by (ii) the Current
         Market Price as of such date.

         "CONVERSION VALUE", as of any date, means the lesser of the AMVESCAP
         Share Value as of such date and $1,200.

         "CORPORATION" means AMVESCAP Inc., a corporation existing under the
         laws of Nova Scotia, and subject to Article 11, its successors and
         assigns.


<PAGE>   9
                                      -3-


         "COUNSEL" means a legal counsel or firm of legal counsel retained by
         the Trustee or retained by the Corporation and acceptable to the
         Trustee.

         "CURRENT MARKET PRICE" means, in respect of an AMVESCAP Ordinary Share
         on any date, the quotient obtained by dividing (i) the aggregate of the
         Daily Value of Trades for each day during the period of 20 consecutive
         Trading Days ending not more than three Trading Days before such date;
         by (ii) the aggregate volume of AMVESCAP Ordinary Shares used to
         calculate such Daily Value of Trades.

         "DAILY VALUE OF TRADES" means, in respect of the AMVESCAP Ordinary
         Shares on any Trading Day, the Canadian Dollar Equivalent of the
         product of (i) the volume weighted average price of AMVESCAP Ordinary
         Shares on the LSE (or, if the AMVESCAP Ordinary Shares are not then
         listed on the LSE, on such other stock exchange or automated quotation
         system on which the AMVESCAP Ordinary Shares are listed or quoted, as
         the case may be, as may be selected by the board of directors of the
         Guarantor for such purpose) on such date, as determined by Bloomberg
         L.P. or other reputable, third party information source selected by the
         board of directors of the Guarantor; and (ii) the aggregate volume of
         AMVESCAP Ordinary Shares traded on such day on the LSE or such other
         stock exchange or automated quotation system; provided that any such
         selections by the board of directors of the Guarantor shall be
         conclusive and binding.

         "DEBENTURES" means, as of any date, the equity subordinated debentures
         of the Corporation issued hereunder and outstanding as of such date.

         "DETERMINATION DATE" means the Business Day that is three Business Days
         prior to the Maturity Date.

         "DIRECTOR" means a director of the Corporation for the time being, and
         "DIRECTORS" or "BOARD OF DIRECTORS" means the board of directors of the
         Corporation or a committee of the board of directors duly authorized to
         make a decision on the matter in question for the time being and
         reference without more to action by the Directors means action by such
         Directors as a board or action by a committee of the Board of Directors
         duly authorized to make a decision on the matter in question.

         "DISTRIBUTED PROPERTY" means all securities (excluding Exchangeable
         Shares and options, rights or warrants to purchase Exchangeable Shares)
         or assets (including dividends, other than cash dividends and stock
         dividends paid in lieu of cash dividends) distributed by way of
         dividend, return of capital or otherwise to registered holders of the
         Exchangeable Shares.

         "EVENT OF DEFAULT" has the meaning attributed thereto in Section 9.1.


<PAGE>   10
                                      -4-


         "EXCHANGEABLE SHARES" means the non-voting exchangeable shares in the
         capital of the Corporation.

         "EXERCISE NOTICE" has the meaning attributed thereto in Section 4.3(2).

         "EXTRAORDINARY CASH DIVIDEND" means in respect of the Exchangeable
         Shares:

         (a)      A cash dividend on the Exchangeable Shares in respect of a
                  particular fiscal year representing the excess, if any, of (i)
                  the aggregate of all cash dividends declared and paid on the
                  AMVESCAP Ordinary Shares in respect of such fiscal year over
                  (ii) the greatest of (A) 200% of the aggregate of all cash
                  dividends declared and paid on the AMVESCAP Ordinary Shares in
                  respect of the year ended December 31, 1999, (B) 300% of the
                  average of the aggregate of all cash dividends declared and
                  paid on the AMVESCAP Ordinary Shares in respect of the
                  immediately preceding three fiscal years, and (C) 100% of the
                  aggregate consolidated net income of the Guarantor, before
                  extraordinary and unusual items, for its immediately preceding
                  fiscal year; and

         (b)      Any cash dividend on the Exchangeable Shares which the
                  Directors by resolution determine to be extraordinary, taking
                  into account the amount of the dividend, the effect of the
                  dividend on the market value of the Exchangeable Shares after
                  payment thereof, the form of payment, the financial position
                  of the Corporation, economic conditions, business practices
                  and such other factors as the Directors consider to be
                  relevant.

         "FREELY TRADEABLE" means, in respect of shares of any class in the
         capital of any corporation, shares which

         (a)      are issuable by such corporation without the necessity of
                  filing a prospectus or any other similar offering document
                  (other than such prospectus or similar offering document that
                  has already been filed) under Applicable Securities
                  Legislation and such issue does not constitute a distribution
                  (other than a distribution already qualified by prospectus or
                  similar offering document) under Applicable Securities
                  Legislation; and

         (b)      can be transferred by the holder thereof without any
                  restriction under Applicable Securities Legislation, such as
                  hold periods except for restrictions on transfer by reason of
                  the holder being a "control person" under Applicable
                  Securities Legislation.

         "GOVERNMENT ENTITY" means any (i) multinational, federal, provincial,
         state, regional, municipal, local or other government, governmental or
         public department, central bank, court, tribunal, arbitral body,
         commission, board, bureau or agency, domestic or foreign, (ii)
         self-regulatory organization or stock


<PAGE>   11
                                      -5-


         exchange (including, without limitation, the LSE, the UKLA and the
         TSE), (iii) any subdivision, agent, commission, board, or authority of
         any of the foregoing, or (iv) any quasi-governmental or private body
         exercising any regulatory, expropriation or taxing authority under or
         for the account of any of the foregoing.

         "GUARANTOR" means AMVESCAP PLC, a corporation existing under the laws
         of England, and subject to Article 11, its successors and assigns.

         "HOLDER(S)" or "DEBENTUREHOLDER(S)" means the registered holder(s) of
         Debentures for the time being.

         "INDEBTEDNESS" includes any liability for any money owing whatsoever
         including, without limitation, in respect of the acquisition of any
         assets or as a result of moneys borrowed or raised by whatever means
         (including, without limitation, by means of commercial paper, bankers'
         acceptances, letters of credit, debt instruments, bank debt or
         financial leases, and any liability evidenced by bonds, debentures,
         notes or similar instruments), the guarantee of any obligations and the
         obligation to indemnify.

         "INDENTURE", "HEREIN", "HEREBY", "HEREOF" and similar expressions mean
         or refer to this Indenture and any indenture, deed or instrument
         supplemental or ancillary hereto; and the expressions "ARTICLE", and
         "SECTION" followed by numbers or letters mean and refer to the
         specified Article or Section of this Indenture.

         "INTEREST PAYMENT DATE" means February 1 and August 1 in each year, the
         first Interest Payment Date being February 1, 2001 and the last
         Interest Payment Date being August 1, 2003.

         "LSE" means the London Stock Exchange plc or its successors.

         "MATURITY DATE" means August 1, 2003.

         "MATURITY NOTICE" has the meaning attributed thereto in Section 4.3(2).

         "OFFER" means a take-over bid or issuer bid to purchase AMVESCAP
         Ordinary Shares, or any other transaction which has a similar effect
         (including any amalgamation, arrangement, consolidation, merger or
         other transaction involving the Guarantor, as a consequence of which
         some or all of the AMVESCAP Ordinary Shares outstanding immediately
         prior to the transaction will be exchanged or transferred for or
         converted into cash, securities or other property of the Guarantor or
         another Person) provided that one of the conditions to the completion
         of such purchase pursuant to such take-over bid or issuer bid


<PAGE>   12
                                      -6-


         or to the completion of such other transaction is that the Debentures
         are redeemed.

         "OFFICERS' CERTIFICATE" means a written certificate signed in the name
         of the Corporation by any two officers of the Corporation.

         "OPINION OF COUNSEL" means a written opinion containing the information
         specified herein from legal counsel who is acceptable to the Trustee,
         acting reasonably.

         "PERSON" includes any individual, firm, partnership, limited
         partnership, joint venture, venture capital fund, limited liability
         company, unlimited liability company, association, trust, trustee,
         executor, administrator, legal personal representative, estate, group,
         body corporate, corporation, unincorporated association or
         organization, Governmental Entity, syndicate or other entity.

         "PLAN" means the Plan of Arrangement attached to the articles of
         arrangement of Trimark Financial Corporation sent to the Director under
         the Business Corporations Act (Ontario) on the date hereof.

         "QUALIFIED INSTITUTION" has the meaning attributed hereto in Section
         14.3.

         "RECOGNIZED STOCK EXCHANGE", with respect to the Exchangeable Shares
         and the Debentures, means the TSE and, with respect to the AMVESCAP
         Ordinary Shares, means the LSE.

         "REDEMPTION AMOUNT" has the meaning attributed thereto in Section 3.1.

         "REDEMPTION DATE" has the meaning attributed thereto in Section 3.1.

         "REDEMPTION NOTICE" has the meaning attributed thereto in Section 3.3.

         "REORGANIZATION EVENT" means any of (i) any amalgamation, arrangement,
         consolidation or merger of the Guarantor, with or into another entity
         that is a corporation (other than an amalgamation, arrangement,
         consolidation or merger in which the Guarantor is the continuing
         corporation and in which the AMVESCAP Ordinary Shares outstanding
         immediately prior to the amalgamation, arrangement, consolidation or
         merger are not exchanged for cash, securities or other property of the
         Guarantor or another corporation); (ii) any sale, transfer, lease or
         conveyance to another corporation of all or substantially all of the
         property of the Guarantor; or (iii) any liquidation, dissolution or
         winding-up of the Guarantor.

         "SENIOR LIABILITIES" means all amounts payable (including, without
         limitation, principal, interest, premiums, fees and expenses) in
         respect of or as a result of all


<PAGE>   13
                                      -7-


         Indebtedness of each of the Corporation (other than the Debentures) and
         the Guarantor, whether outstanding on the date of this Indenture or
         thereafter created, incurred, assumed or guaranteed by the Corporation
         and/or the Guarantor other than Indebtedness of the Corporation or the
         Guarantor which at any time at the option of such corporation is
         convertible into or exchangeable for Exchangeable Shares or any other
         class of shares of such corporation or Indebtedness of the Corporation
         or the Guarantor which, pursuant to the terms of the instrument
         creating or evidencing such Indebtedness, does not rank prior in right
         of payment to the Debentures.

         "SHARE REDEMPTION RIGHT" has the meaning attributed thereto in Section
         3.6(1).

         "SHARE REPAYMENT RIGHT" has the meaning attributed thereto in Section
         4.3(1).

         "SUBSIDIARY" means, with respect to a specified body corporate, any
         body corporate of which more than 50% of the outstanding shares
         ordinarily entitled to elect a majority of the board of directors
         thereof (whether or not shares of any other class or classes shall or
         might be entitled to vote upon the happening of any event or
         contingency) are at the time owned directly or indirectly by such
         specified body corporate and shall include any body corporate,
         partnership, joint venture or other entity over which it exercises
         direction or control or which is in a like relation to a subsidiary.

         "SUCCESSOR CORPORATION" has the meaning attributed thereto in Section
         11.1.

         "TRADING DAY" means, with respect to a Recognized Stock Exchange or
         other market for securities, any day on which such exchange or market
         is open for trading or quotation.

         "TRUSTEE" means CIBC Mellon Trust Company and its successors hereunder.

         "TSE" means The Toronto Stock Exchange Inc. or its successors.

         "UKLA" means the UK Listing Authority, namely the Financial Services
         Authority in its capacity as the competent authority for the purposes
         of Part IV of the Financial Services Act, 1986 of the United Kingdom
         (or any successor Act).

         "WRITTEN ORDER" or "WRITTEN REQUEST" means a written order or request,
         respectively, signed in the name of the Corporation by an authorized
         officer of the Corporation.

(2)      Words importing the singular number include the plural and vice versa
         and words importing gender include the masculine, feminine and neuter
         genders.


<PAGE>   14
                                      -8-


(3)      Except as otherwise provided herein, any reference in this Indenture to
         any act, statute, regulation, rule, instrument, agreement or section
         thereof shall be deemed to be a reference to such act, statute,
         regulation, rule, instrument, agreement or section thereof as amended,
         re-enacted or replaced from time to time.

(4)      Any reference in this Indenture to "DOLLARS" or the sign "$" shall be
         deemed to be a reference to lawful money of Canada.

SECTION 1.2 MEANING OF "OUTSTANDING" FOR CERTAIN PURPOSES.

         Every Debenture shall be deemed to be outstanding until it shall be
cancelled or delivered to the Trustee for cancellation (for greater certainty,
delivery of any Debentures to the Trustee for conversion, redemption or on
maturity is not delivery for cancellation until the Holder of such Debentures
has received all monies and/or securities it is entitled to receive in such
event) or until moneys and/or securities for the payment thereof shall be set
aside under Article 10, or until it shall have become void pursuant to Section
2.4, provided however, that where a new Debenture has been issued in
substitution for a Debenture which has been lost, stolen or destroyed, only one
of such Debentures shall be counted for all purposes, including, without
limitation, the purpose of determining the aggregate principal amount of
Debentures outstanding, and provided that, for the purpose of any provision of
this Indenture entitling Holders of Debentures then outstanding to vote,
constitute a quorum for the purpose of voting, sign consents, requisitions or
other instruments or take any other action under this Indenture, Debentures
owned, directly or indirectly, legally or beneficially by the Corporation or any
Affiliate shall be disregarded, except that (i) for the purpose of determining
whether the Trustee shall be protected in relying on any vote, constitution of a
quorum, consent, requisition, instrument or other action, only those Debentures
which according to an Officers' Certificate received by the Trustee are so owned
shall be disregarded; and (ii) Debentures so owned which have been pledged in
good faith other than to the Corporation or any Affiliate shall not be so
disregarded, if the pledgee shall establish to the satisfaction of the Trustee
the pledgee's right to vote such Debentures in its discretion, free from the
control of the Corporation or any Affiliate.

SECTION 1.3 ACTS OF HOLDERS

(1)      Any request, demand, authorization, direction, notice, consent, waiver
         or other action provided by this Indenture to be given or taken by
         Holders may be embodied in and evidenced by one or more instruments of
         substantially similar tenor signed by such Holders in person or by
         agents duly appointed in writing or, alternatively, be embodied in and
         evidenced by the record of Debentureholders voting in favour thereof,
         either in person or by proxies duly appointed in writing, at any
         meeting of Debentureholders duly called and held in accordance with the
         provisions of Article 12, or a combination of such instruments and any
         such record. Except as herein otherwise expressly


<PAGE>   15
                                      -9-


         provided, such action shall become effective when such requisite
         instrument or instruments are delivered to the Trustee and, where it is
         hereby expressly required, to the Corporation. Such instrument or
         instruments (and the action embodied therein and evidenced thereby) are
         herein sometimes referred to as the "ACT" of the Holders signing such
         instrument or instruments. Proof of execution of any such instrument or
         of a writing appointing any such agent shall be sufficient for any
         purpose of this Indenture and, subject to Section 14.1, conclusive in
         favour of the Trustee and the Corporation, if made in the manner
         provided in this Section. The record of any meeting of Debentureholders
         shall be provided in the manner provided in Section 12.6.

(2)      The fact and date of the execution by any Person of any such instrument
         or writing may be proved by the affidavit of a witness of such
         execution or by a certificate of a notary public or other officer
         authorized by law to take acknowledgements of deeds, certifying that
         the individual signing such instrument or writing acknowledged to him
         or her the execution thereof. Where such execution is by a signer
         acting in a capacity, other than his or her individual capacity, such
         certificate or affidavit shall also constitute sufficient proof of his
         or her authority. The fact and date of the execution of any such
         instrument or writing, or the authority of the Person executing the
         same, may also be proved in any manner that the Trustee deems
         sufficient.

(3)      If the Corporation or the Trustee shall solicit from the
         Debentureholders any Act, the Corporation or the Trustee, as the case
         may be, may, at its option, fix in advance a record date for the
         determination of Debentureholders entitled to take such Act, but the
         Corporation or the Trustee, as the case may be, shall have no
         obligation to do so. Any such record date shall be fixed at the
         Corporation's or the Trustee's discretion, as the case may be. If such
         a record date is fixed, such Act may be sought or taken before or after
         the record date, but only the Debentureholders of record at the close
         of business (in the City of Toronto, Ontario) on such record date shall
         be deemed to be Debentureholders for the purpose of determining whether
         Holders of the requisite proportion of Debentures then outstanding have
         authorized or agreed or consented to such Act, and for that purpose the
         Debentures then outstanding shall be computed as of such record date.

(4)      Any Act of the Holder of a Debenture shall bind every future holder of
         the same Debenture and the Holder of every Debenture issued upon the
         registration of transfer thereof or in exchange therefor or in lieu
         thereof in respect of anything done, suffered or omitted by the Trustee
         or the Corporation in reliance thereon, whether or not notation of such
         action is made upon such Debenture.


<PAGE>   16
                                      -10-


SECTION 1.4 INTERPRETATION NOT AFFECTED BY HEADINGS, ETC.

         The division of this Indenture into Articles and Sections, the
provision of a table of contents and the insertion of headings are for
convenience of reference only and shall not affect the construction or
interpretation hereof.

SECTION 1.5 APPLICABLE LAW.

(1)      This Indenture and the Debentures shall be governed by and construed in
         accordance with the laws of the Province of Ontario and the laws of
         Canada applicable therein.

(2)      The parties hereby irrevocably attorn and submit to the non-exclusive
         jurisdiction of the courts of Ontario with respect to any matter
         arising under or related to the Indenture and the Debentures.

SECTION 1.6 INVALIDITY PROVISIONS.

         If any provision contained in this Indenture or the Debentures should
be invalid, illegal or unenforceable in any respect, the validity, legality or
enforceability of the remaining provisions contained herein and therein shall
not in any way be affected or impaired thereby.

SECTION 1.7 LANGUAGE.

         This Indenture and all matters related hereto shall be read, construed
and enforced in the English language, and unless otherwise specified herein, all
notices, statements of account and other documents signed or permitted to be
given or entered into pursuant hereto shall be drawn up in the English language
only. The parties hereto expressly request and require that this document be
drawn up in English. Les parties aux presentes conviennent et exigent que cette
entente et tous les documents qui s'y rattachent soient rediges en anglais.

SECTION 1.8 SUCCESSORS AND ASSIGNS.

         All covenants and agreements in this Indenture by the Corporation and
the Guarantor shall bind their respective successors and assigns, whether
expressed or not.

SECTION 1.9 BENEFITS OF INDENTURE.

         Nothing in this Indenture or in the Debentures, express or implied,
shall give to any Person, other than the parties hereto and their successors
hereunder, any paying agent and the Holders, any benefit or any legal or
equitable right, remedy or claim under this Indenture.


<PAGE>   17
                                      -11-


                                    ARTICLE 2
                                 THE DEBENTURES

SECTION 2.1 LIMIT OF ISSUE AND DESIGNATION OF DEBENTURES.

         The Debentures authorized to be issued hereunder shall consist of, and
be limited to, an aggregate maximum principal amount of ONE BILLION, TWO HUNDRED
AND SEVENTY-NINE MILLION, FIVE HUNDRED AND THIRTY THOUSAND Dollars
($1,279,530,000.00) designated as "AMVESCAP EQUITY SUBORDINATED DEBENTURES".

SECTION 2.2 FORM AND TERMS OF DEBENTURES.

(1)      The Debentures shall be dated as of August 1, 2000, shall bear interest
         from and including that date at the rate of 6.00% per annum (after as
         well as before maturity, default and judgment, with interest on overdue
         interest at such rate), payable in equal semi-annual instalments in
         arrears in lawful money of Canada on each Interest Payment Date, and
         shall mature on the Maturity Date.

(2)      Subject to exercise of (i) the right to redeem pursuant to Article 3;
         (ii) the right to convert pursuant to Section 4.1 or Section 4.3; and
         (iii) the Share Repayment Right pursuant to Section 4.3, the principal
         of the Debentures will be payable on the Maturity Date in lawful money
         of Canada against surrender thereof by the registered Holder of the
         Debentures at the place at which the register is maintained pursuant to
         Section 2.9.

(3)      The Debentures shall be issued as fully registered Debentures in
         denominations of $1,000 and integral multiples of $1,000, shall be
         redeemable as provided for in Article 3 and shall be convertible as
         provided for in Article 4.

(4)      The Debentures and the certificate of the Trustee endorsed thereon
         shall be substantially in the form set forth in Schedule "A" hereto.

(5)      Subject to applicable law and the rules of the TSE, the Debentures may
         be printed, engraved or lithographed or may be partly in one form and
         partly in the other, as the Corporation may determine.

SECTION 2.3 INTEREST.

         Each Debenture issued hereunder, whether issued originally or in
exchange for another Debenture, shall bear interest daily from and including
August 1, 2000 or from and including the last Interest Payment Date on which
interest shall have been paid or made available for payment on the Debentures
then outstanding, whichever shall be the later, to but excluding the earlier of:

         (a)      If called for redemption, the Redemption Date;


<PAGE>   18
                                      -12-


         (b)      If converted prior to Maturity Date in accordance with Section
                  4.1, the Conversion Date; and

         (c)      The Maturity Date;

unless such payment is improperly withheld or refused, upon due presentation and
surrender thereof for payment on or after the appropriate date and prior to the
setting aside of the appropriate amount pursuant to Article 10. In addition,
interest shall be payable on the Conversion Value in accordance with the
provisions of Section 4.4.

SECTION 2.4 PRESCRIPTION.

         The right of the Debentureholders to exercise their rights under this
Indenture shall become void unless the Debentures are presented for payment
within a period of five years from the Maturity Date, after which payment
thereof shall be governed by the provisions of Article 10. The Corporation shall
have satisfied its obligations under a Debenture upon remittance to the Trustee
for the account of the Holder thereof, either upon redemption, on the Conversion
Date for such Debenture or on the Maturity Date, of any and all consideration
due hereunder in respect of such Debenture in cash or by the delivery of Freely
Tradeable Exchangeable Shares, subject to and in accordance with the provisions
of this Indenture, and such remittance shall for all purposes be deemed a
payment to such Holder, and to that extent such Debenture shall thereafter not
be considered as outstanding and such Holder shall have no right, except to
receive payment out of the moneys so paid and deposited or Freely Tradeable
Exchangeable Shares so deposited (or, after redemption or purchase of the
Exchangeable Shares pursuant to their terms or to the terms of the Plan,
AMVESCAP Ordinary Shares) upon surrender of such Debenture.

SECTION 2.5 ISSUE OF DEBENTURES.

(1)      Debentures in the aggregate maximum principal amount of ONE BILLION,
         TWO HUNDRED SEVENTY-NINE MILLION, FIVE HUNDRED AND THIRTY THOUSAND
         Dollars ($1,279,530,000.00) in lawful money of Canada shall be executed
         by the Corporation and, forthwith after such execution, shall be
         delivered to the Trustee and shall be certified by the Trustee and
         delivered to or to the order of the Corporation upon receipt by the
         Trustee of the following:

         (a)      A Written Order for the certification and delivery of such
                  Debentures;

         (b)      An Opinion of Counsel (who may rely, as to all factual
                  matters, in the absence of knowledge to the contrary, upon an
                  Officers' Certificate and which may be subject to customary
                  qualifications) in favour of the Trustee to the effect that:


<PAGE>   19
                                      -13-


                  (i)      All conditions precedent provided for herein relating
                           to the authorization, execution, authentication and
                           delivery of the Debentures applied for have been
                           complied with; and

                  (ii)     The Debentures applied for have been duly and validly
                           authorized, executed and delivered by the Corporation
                           and, upon certification and delivery thereof by the
                           Trustee, will be valid and legally binding
                           obligations of the Corporation, entitled to the
                           benefits hereof and subject to the terms hereof; and

         (c)      An Officers' Certificate stating that all conditions precedent
                  provided for herein relating to the authorization, issuance,
                  execution, certification and delivery of the Debentures
                  applied for have been complied with.

(2)      The Trustee, prior to the certification of the Debentures, shall not be
         bound to make any enquiry or investigation as to the correctness of the
         matters set forth in any of the opinions, certificates or other
         documents required by the provisions hereof. The Trustee may rely and
         shall be protected in acting upon any such opinions, certificates or
         other documents, but may in its discretion require additional evidence
         before acting or relying thereon.

SECTION 2.6 CONCERNING INTEREST.

         Wherever in this Indenture there is mention in any context of the
payment of interest, such mention shall be deemed to include mention of the
payment of interest on amounts in default to the extent that, in such context,
such interest is, was, or would be payable and express mention of interest on
amounts in default in any provisions hereof shall not be construed as excluding
such interest in those provisions hereof where such express mention is not made.

SECTION 2.7 EXECUTION OF DEBENTURES.

         The Debentures shall be signed by the President of the Corporation and
by the Secretary of the Corporation. The signatures of such officers may be
reproduced in facsimile and Debentures bearing such facsimile signatures shall
be binding upon the Corporation, as if they had been manually signed by such
officers. Notwithstanding that any of the individuals whose manual or facsimile
signature appears on any Debenture as one of such officers may no longer hold
office at the date of this Indenture or at the date of such Debenture or at the
date of certification and delivery thereof, any Debenture signed as aforesaid
shall be valid and binding upon the Corporation and entitled to the benefit
hereof.

SECTION 2.8 CERTIFICATION BY THE TRUSTEE.

(1)      No Debenture shall be issued or, if issued, shall be obligatory or
         entitle the Holder to the benefit hereof, until it has been certified
         by or on behalf of the


<PAGE>   20
                                      -14-


         Trustee substantially in the form of the certificate set out in
         Schedule "A" hereto, or in some other form approved by the Trustee, and
         such certification by the Trustee upon any Debenture shall be
         conclusive evidence that the Debenture so certified has been duly
         issued hereunder and is a valid obligation of the Corporation and that
         the Holder is entitled to the benefit hereof.

(2)      The certificate of the Trustee on Debentures issued hereunder shall not
         be construed as a representation or warranty by the Trustee as to the
         validity of this Indenture or of the Debentures (except the due
         certification thereof) or as to the performance by the Corporation or
         the Guarantor of their obligations under this Indenture and the Trustee
         shall in no respect be liable or answerable for the use made of the
         Debentures or any of them or of the proceeds thereof (other than
         disbursement of amounts received from the Corporation in respect of the
         payment of interest or principal pursuant to this Indenture).

SECTION 2.9 REGISTRATION OF DEBENTURES.

(1)      The Corporation shall cause to be kept by and at the principal office
         of the Trustee in the City of Toronto, Ontario a Debenture register in
         which shall be entered the names and latest known addresses of the
         Holders of Debentures and the other particulars, prescribed by law, of
         the Debentures held by them respectively and of all transfers of
         Debentures. Such name registration shall be noted on the Debentures by
         the Trustee or other registrar. No transfer of a Debenture shall be
         effective as against the Corporation unless made on the Debenture
         register and made by the registered Holder or its executors or
         administrators or other legal representatives or its or their attorney
         duly appointed by an instrument in writing in form and execution
         satisfactory to the Trustee, upon compliance with such requirements as
         the Trustee or other registrar may prescribe, and unless such transfer
         shall have been duly noted on such Debenture by the Trustee or other
         registrar.

(2)      The Holder of a Debenture may at any time and from time to time have
         such Debenture transferred at the place at which the register is kept
         pursuant to the provisions of this Section and in accordance with such
         reasonable regulations as the Trustee may prescribe.

(3)      The party requesting any transfer pursuant to this Section 2.9 shall,
         as a condition precedent to such transfer, reimburse the Trustee for
         any stamp or other security transfer tax or governmental charge
         required to be paid in respect of such transfer and, in addition, pay a
         reasonable charge for the Trustee's services for each Debenture
         transferred and for each Debenture issued upon such transfer.

(4)      Neither the Corporation nor the Trustee nor any registrar shall be
         required to transfer or exchange (pursuant to Section 2.12) any
         Debentures on any Interest


<PAGE>   21
                                      -15-


         Payment Date or Redemption Date or for a period of 15 Business Days
         preceding any Interest Payment Date or Redemption Date.

(5)      None of the Trustee or any registrar for the Debentures or the
         Corporation shall be charged with notice of or be bound to see to the
         execution of any trust, whether express, implied or constructive, in
         respect of any Debenture and may transfer any Debenture on the
         direction of the Holder thereof, whether named as trustee or otherwise,
         as though that Person were the beneficial owner thereof.

SECTION 2.10 PERSON ENTITLED TO PAYMENT.

(1)      The Person in whose name any Debentures shall be registered shall be
         deemed the owner thereof for all purposes of this Indenture and payment
         of or on account of the principal and accrued interest on such
         Debentures shall be made only to or upon the order in writing of such
         Holder thereof and such payment shall be a good and sufficient
         discharge to the Trustee and any registrar and to the Corporation and
         any paying agent for the amount so paid.

(2)      Subject to the exercise of the Share Redemption Right pursuant to
         Section 3.6 or a Holder's conversion right pursuant to Section 4.1, as
         the interest on the Debentures becomes payable (except interest payable
         at maturity, conversion or on redemption which may, at the option of
         the Corporation, be paid upon presentation and surrender of such
         Debentures for payment), the Corporation, at least three (3) days prior
         to each Interest Payment Date, shall forward or cause to be forwarded
         by prepaid post (or in the event of mail service interruption by such
         other means as the Trustee and the Corporation shall determine to be
         appropriate), to the Holder of each Debenture, at its address appearing
         on the register referred to in Section 2.9, or in the case of joint
         Holders, to the one whose name appears first on such register, a cheque
         for such interest (less any tax required by law to be deducted) payable
         to the order of such Holder or Holders and negotiable at par at the
         City of Toronto, Ontario. The forwarding of such cheque shall satisfy
         and discharge the liability for the interest on the Debentures to the
         extent of the sums represented thereby (plus the amount of any tax
         deducted as aforesaid), unless such cheque be not paid on presentation;
         provided that, in the event of the non-receipt of such cheque by the
         Holder, or the loss or destruction thereof, the Corporation, upon it
         and the Trustee being furnished with reasonable evidence of such
         non-receipt, loss or destruction and indemnity reasonably satisfactory
         to them shall issue to such Holder a replacement cheque for the amount
         of such cheque.

(3)      The registered Holder of any Debenture shall be entitled to the
         principal and interest evidenced by such Debenture, free from all
         equities or rights of set-off, compensation or counterclaim between the
         Corporation and the original or any intermediate Holder thereof and all
         Persons may act accordingly and a transferee


<PAGE>   22
                                      -16-


         of a Debenture shall, after the appropriate form of transfer is lodged
         with the Trustee or other registrar and upon compliance with all other
         conditions in that behalf required by this Indenture or by any
         conditions contained in such Debenture or by law, be entitled to be
         entered on the Debenture register as the owner of such Debenture, free
         from all equities or rights of set-off, compensation or counterclaim
         between the Corporation and its transferor or any previous Holder
         thereof, save in respect of equities of which the Corporation is
         required to take notice by statute or by order of a court of competent
         jurisdiction.

(4)      Where Debentures are registered in more than one name, the principal
         and interest from time to time payable in cash in respect thereof may
         be paid by cheque payable to the order of all such Holders, failing
         written instructions from them to the contrary, and such payment shall
         be a valid discharge to the Trustee and any registrar and to the
         Corporation and any paying agent for the amount so paid.

SECTION 2.11 REPLACEMENT OF DEBENTURES.

(1)      If any of the Debentures shall become mutilated or defaced, or be lost,
         stolen or destroyed, the Corporation shall issue and thereupon the
         Trustee shall certify and deliver a new Debenture of like date and
         tenor and bearing the same legends, if any, as the one mutilated,
         defaced, lost, stolen or destroyed in exchange for, in place of and
         upon cancellation of such mutilated or defaced Debenture or in lieu of
         and in substitution for such lost, stolen or destroyed Debenture. The
         new Debenture shall be entitled to the benefit hereof and shall rank
         equally in accordance with its terms with all other Debentures issued
         hereunder.

(2)      The applicant for the issue of a new Debenture shall bear the cost of
         the issue thereof and in case of loss, destruction or theft shall, as a
         condition precedent to the issue thereof, furnish to the Corporation
         and the Trustee such evidence of ownership and of the loss, destruction
         or theft of the Debenture so lost, destroyed or stolen as shall be
         satisfactory to the Corporation and the Trustee in their discretion and
         such applicant shall also be required to furnish indemnity in amount
         and form satisfactory to the Corporation and the Trustee in their
         discretion, and shall pay the reasonable charges of the Corporation and
         the Trustee in connection therewith.

SECTION 2.12 EXCHANGE OF DEBENTURES.

(1)      Debentures in any denomination may be exchanged at any time for
         Debentures of the same aggregate principal amount in any other
         authorized denomination. Debentures may be so exchanged at the place at
         which the register is maintained pursuant to Section 2.9 or other
         convenient place of delivery by the Corporation and acceptable to the
         Trustee.


<PAGE>   23
                                      -17-


(2)      The Corporation shall execute and the Trustee shall certify all
         Debentures necessary to carry out exchanges pursuant to this Section
         2.12. All Debentures surrendered for exchange shall be cancelled.

(3)      The party requesting any exchange pursuant to this Section 2.12 shall,
         as a condition precedent to such exchange, reimburse the Trustee for
         any stamp or other security transfer tax or governmental charge
         required to be paid in respect of such exchange or the related issue of
         Debentures and, in addition, pay a reasonable charge for the Trustee's
         services for each Debenture exchanged and a reasonable charge for each
         Debenture issued upon such exchange.

(4)      Notwithstanding the foregoing provisions, no charge for the Trustee's
         services shall be made to a Debentureholder for any exchange or
         transfer of any Debenture applied for within a period of 60 days from
         the date hereof.

SECTION 2.13 REGISTER OPEN FOR INSPECTION.

         The Debenture register shall at all reasonable times, and at such
reasonable costs as established by the Trustee or other registrar, be open for
inspection by the Corporation, the Guarantor, the Trustee or any
Debentureholder. The Trustee and every registrar shall from time to time when
requested in writing to do so by the Corporation, the Guarantor or by the
Trustee furnish the Corporation, the Guarantor or the Trustee, as the case may
be, with a list of names and addresses of Holders of Debentures entered on the
register kept by it and showing the principal amount and serial numbers of the
Debentures held by each such Holder.

SECTION 2.14 PAYMENT OF INTEREST AND PRINCIPAL.

(1)      Except as herein otherwise provided, all sums which may at any time
         become payable, whether at maturity, conversion, redemption or on a
         declaration of acceleration or otherwise, on account of any Debenture
         or any interest thereon, shall be payable at the option of the Holder
         at the place at which the register referred to in Section 2.9 is
         maintained.

(2)      Whenever any payment of principal or interest to be made hereunder
         shall be stated to be due on a day which is not a Business Day in the
         place in which the register referred to in Section 2.9 is maintained,
         then the Debentureholder shall not be entitled to payment of the amount
         due in such place until the next succeeding Business Day in that place
         and will not be entitled to interest or other payment in respect of
         such delay.

SECTION 2.15 RANK AND SUBORDINATION.

         The Debentures certified and issued under this Indenture rank pari
passu with one another, in accordance with their tenor without discrimination,
preference or priority. The payment of all amounts owing hereunder including,
without limitation,


<PAGE>   24
                                      -18-


the principal of and interest on the Debentures is expressly subordinated to the
prior payment in full of Senior Liabilities, as provided in Article 6.

SECTION 2.16 NOTICE TO DEBENTUREHOLDERS.

(1)      All notices to be given hereunder with respect to the Debentures shall
         be deemed to be validly given to the Debentureholders if sent by
         courier or by first class mail, postage prepaid, by letter or circular
         addressed to such Holders at their post office addresses appearing in
         the register referred to in Section 2.9. Any notice so given by courier
         or mail shall be deemed to have been received one (1) Business Day
         after the day it was given to the courier or three (3) Business Days
         after the day of mailing. If by reason of any interruption of mail
         service, actual or threatened, any notice to be given to all
         Debentureholders would be unlikely to reach substantially all of the
         Debentureholders such notice may be given by publication once (twice in
         the case of a notice of a meeting of Debentureholders) in any daily
         English language newspaper of general circulation in all provinces of
         Canada and once in a daily French language newspaper of general
         circulation in the Province of Quebec. Any notice so given by
         publication shall be deemed to have been received on the day on which
         publication shall have been effected at least once in each of the
         newspapers in which publication was required.

(2)      Accidental error or omission in giving notice or accidental failure to
         send notice by mail or courier to any Debentureholder shall not
         invalidate any action or proceeding founded such notice.

(3)      All notices with respect to any Debenture may be given to whichever one
         of the Holders thereof (if more than one) is named first in the
         Debenture register and any notice so given shall be sufficient notice
         to all Holders of such Debenture.

(4)      In determining under any provision hereof the date when notice of any
         meeting or other event must be given, the date of giving the notice
         shall be included and the date of the meeting or other event shall be
         excluded.

SECTION 2.17 NOTICE TO THE TRUSTEE.

         Any notice to the Trustee under any provision of this Indenture must be
in writing and may be made or given by personal delivery, by registered mail,
postage prepaid, or by transmittal by facsimile or other electronic means of
communication addressed to the Trustee at 320 Bay Street, P.O. Box 1, Toronto,
Ontario, Canada M5H 4A6 or facsimile (416) 643-5570, Attention: Vice President,
Corporate Trust Services. Except as otherwise expressly provided herein, any
notice given by personal delivery or registered mail shall be deemed to have
been given and received on the day upon which it was delivered or if made or
given by facsimile or other electronic means of communication before 5:00 p.m.
(Toronto time), on the day of transmittal thereof, provided that if such day is
not a Business Day or if such notice was made or given after


<PAGE>   25
                                      -19-


5:00 p.m. (Toronto time), such notice shall be deemed to have been given and
received on the first Business Day after the day of transmittal thereof.

SECTION 2.18 NOTICE TO THE CORPORATION AND TO THE GUARANTOR.

         Any notice to the Corporation or to the Guarantor under any provision
of this Indenture must be in writing and may be made or given by personal
delivery, by registered mail, postage prepaid, or by transmittal by facsimile or
other electronic means of communication addressed to the Corporation or to the
Guarantor c/o AMVESCAP PLC at 11 Devonshire Square, London, England, EC2M 2Y2,
or facsimile (011) 44-207-929-5889, Attention: Corporate Secretary, with a copy
to AMVESCAP Corporation at 1315 Peachtree Street, N.E., Suite 500, Atlanta,
Georgia, USA 30309 or facsimile (404) 724-4280 Attention: Chief Financial
Officer. Except as otherwise expressly provided herein, any notice given by
personal delivery or registered mail shall be deemed to have been given and
received on the day upon which it was delivered or if made or given by facsimile
or other electronic means of communication before 5:00 p.m. (London, England
time), on the day of transmittal thereof, provided that if such day is not a
Business Day or if such notice was made or given after 5:00 p.m. (London,
England time), such notice shall be deemed to have been given and received on
the first Business Day after the day of transmittal thereof.

SECTION 2.19 CHANGE IN ADDRESS.

         Each of the Corporation, the Guarantor or the Trustee may from time to
time notify the other parties of a change in address or facsimile number which
thereafter, until changed by like notice, shall be the address or facsimile
number of that party for all purposes of this Indenture.

SECTION 2.20 MAIL SERVICE INTERRUPTION.

         If by reason of any interruption of mail service, actual or threatened,
any notice to be given to the Trustee, to the Corporation or to the Guarantor
would be unlikely to reach its destination in a timely manner, such notice, if
sent by mail, shall be valid and effective only when received by an officer of
the party to which it is addressed.

                                    ARTICLE 3
                      REDEMPTION, PURCHASE AND CANCELLATION

SECTION 3.1 REDEMPTION OF DEBENTURES.

         The Corporation shall have the right at its option to conditionally or
unconditionally redeem all, but not less than all, of the Debentures outstanding
hereunder at any time before the Maturity Date at a date chosen by the
Corporation for redemption (the "REDEMPTION DATE") upon payment in lawful money
of Canada of an amount, for each $1,000 principal amount of Debentures to be
redeemed, equal to the aggregate of (i) $1,200; plus (ii) all accrued and unpaid
interest on each such $1,000


<PAGE>   26
                                      -20-


principal amount to but excluding the Redemption Date (collectively, the
"REDEMPTION AMOUNT"). The Corporation may satisfy the Redemption Amount in cash
or by the delivery of a number of Freely Tradeable Exchangeable Shares as
provided in Section 3.6. The Corporation may only exercise its right to
conditionally redeem all of the Debentures outstanding hereunder if there is an
Offer and if the only condition to the Corporation's exercise of its right to
redeem all of the Debentures outstanding hereunder is the completion of such
Offer.

SECTION 3.2 PLACES OF PAYMENT.

         The Redemption Amount (less any tax required by law to be deducted)
will be payable upon presentation and surrender of the Debentures called for
redemption at the place where the register is maintained pursuant to Section 2.9
and at any other places specified in the Redemption Notice.

SECTION 3.3 NOTICE OF REDEMPTION.

(1)      Notice of redemption of the Debentures shall be given to Holders at
         least 20 days and not more than 30 days prior to the Redemption Date
         (the "REDEMPTION NOTICE") in the form set forth in Schedule "B" hereto
         and in the manner provided in Section 2.16. Every such notice shall
         specify the aggregate principal amount of Debentures called for
         redemption, the Redemption Date, the Redemption Amount and the places
         of payment and shall state that, subject to Section 3.4, interest upon
         the principal amount of Debentures called for redemption shall cease to
         be payable from and after the Redemption Date. Contemporaneously with
         the giving of such Redemption Notice, the Corporation shall issue a
         press release over newswire services in Canada and the United Kingdom
         advising Debentureholders that such a Redemption Notice has been given
         and containing substantially the information contained in such
         Redemption Notice.

(2)      The Corporation shall notify the Trustee in writing that the
         Corporation is considering redeeming the Debentures at least 5 Business
         Days prior to the date the Corporation may want the Trustee to send a
         Redemption Notice to Debentureholders.

SECTION 3.4 DEBENTURES DUE ON REDEMPTION DATE.

         Upon a Redemption Notice being given in accordance with Section 3.3,
the Redemption Amount shall be and become due and payable on the Redemption Date
specified in such notice and with the same effect as if it were the Maturity
Date of such Debentures and, from and after such Redemption Date, interest shall
cease, unless payment of the Redemption Amount shall not be made on presentation
for surrender of such Debentures at the place specified in Section 3.2 on or
after the Redemption Date and prior to the setting aside of the Redemption
Amount pursuant to Article 10.


<PAGE>   27
                                      -21-


SECTION 3.5 DEPOSIT OF REDEMPTION MONIES.

         Upon Debentures being called for redemption as provided for in Section
3.3 hereof, but subject to Section 3.6, the Corporation shall deposit with the
Trustee or any paying agent to the order of the Trustee or for the account of
the Trustee, on or prior to the Redemption Date specified in the Redemption
Notice, such sums as are sufficient to pay the Redemption Amount of the
Debentures (less any tax required by law to be deducted). From the sums so
deposited, the Trustee shall pay or cause to be paid to the Holders, upon
surrender of the Debentures, the Redemption Amount thereof (less any tax
required by law to be deducted).

SECTION 3.6 RIGHT TO REPAY REDEMPTION AMOUNT IN EXCHANGEABLE SHARES.

(1)      Subject to the other provisions of this Section 3.6, the Corporation
         may, at its option, elect to satisfy its obligation to pay the
         Redemption Amount by delivering to the Trustee on the Redemption Date
         that number of Freely Tradeable Exchangeable Shares obtained by
         dividing the Redemption Amount by 95% of the Current Market Price on
         the date of the Redemption Notice (the "SHARE REDEMPTION RIGHT").

(2)      The Corporation shall exercise the Share Redemption Right by so
         specifying in the Redemption Notice.

(3)      The Corporation's right to exercise the Share Redemption Right shall be
         conditional upon the following conditions being met on the fifth
         Business Day preceding the Redemption Date:

         (a)      The qualification of the Exchangeable Shares to be issued on
                  exercise of the Share Redemption Right as Freely Tradeable;

         (b)      The listing (or the functional equivalent thereof) of such
                  additional Exchangeable Shares on the TSE;

         (c)      The Corporation being a reporting issuer in good standing (or
                  its equivalent) under Applicable Securities Legislation where
                  the distribution of such Exchangeable Shares occurs and where
                  such legislation recognizes the status of a reporting issuer
                  (or its equivalent);

         (d)      No Event of Default shall have occurred and be continuing;

         (e)      The receipt by the Trustee of an Officers' Certificate stating
                  that conditions (a), (b), (c) and (d) above have been
                  satisfied and setting forth the number of Exchangeable Shares
                  to be delivered for each $1,000 principal amount of Debentures
                  and the Current Market Price on the date of the Redemption
                  Notice; and


<PAGE>   28
                                      -22-


         (f)      The receipt by the Trustee of an Opinion of Counsel to the
                  effect that such Exchangeable Shares have been duly authorized
                  and, when issued and delivered pursuant to the terms of this
                  Indenture in payment of the Redemption Amount of the
                  Debentures outstanding, will be validly issued as fully paid
                  and non-assessable, that conditions (a) and (b) above have
                  been satisfied and that, relying exclusively on certificates
                  of good standing issued by the relevant securities
                  authorities, condition (c) above is satisfied, except that
                  such opinion in respect of condition (c) need not be expressed
                  with respect to those provinces where certificates of good
                  standing are not issued by the securities authorities.

         If the foregoing conditions are not satisfied prior to the close of
         business (in the City of Toronto, Ontario) on the fifth Business Day
         preceding the Redemption Date, the Corporation shall pay the Redemption
         Amount in cash in accordance with Section 3.5 and shall issue a press
         release over newswire services in Canada and the United Kingdom to such
         effect.

(4)      In the event that the Corporation duly exercises its Share Redemption
         Right, on or before the Redemption Date, the Corporation shall deliver
         or cause to be delivered to the Trustee for delivery to and on account
         of the Holders upon presentation and surrender of the Debentures for
         payment on redemption at the place where the register is maintained
         pursuant to Section 2.9 or any other place specified in the Redemption
         Notice, certificates representing the Freely Tradeable Exchangeable
         Shares to which the Holders are entitled.

(5)      No fractional Exchangeable Shares shall be delivered upon the exercise
         of the Share Redemption Right but, in lieu thereof, the Corporation
         shall pay to the Trustee for the account of the Holders, at the time
         contemplated in Section 3.6(4), the cash equivalent thereof determined
         on the basis of the Current Market Price on the date of the Redemption
         Notice (less any tax required by law to be deducted).

(6)      A Holder shall be treated as the shareholder of record of the
         Exchangeable Shares issued on due exercise by the Corporation of the
         Share Redemption Right effective immediately after the close of
         business (in the City of Toronto, Ontario) on the Redemption Date, and
         shall be entitled to all substitutions therefor, all income earned
         thereon or accretions thereto and all dividends or distributions
         (including stock dividends and dividends or distributions in kind)
         thereon and arising thereafter, and in the event that the Trustee
         receives the same, it shall hold the same in trust for the benefit of
         such Holder.

(7)      The Corporation shall at all times reserve and keep available out of
         its authorized Exchangeable Shares (if the number thereof is or becomes
         limited) solely for the purpose of issue and delivery upon the exercise
         of the Share Redemption Right


<PAGE>   29
                                      -23-


         as provided herein, and shall issue to Debentureholders to whom
         Exchangeable Shares will be issued pursuant to exercise of the Share
         Redemption Right, such number of Exchangeable Shares as shall be
         issuable in such event. All Exchangeable Shares which shall be so
         issuable shall be duly and validly issued as fully paid and
         non-assessable.

(8)      The Corporation shall comply with all Applicable Securities Legislation
         regulating the Corporation and the issue and delivery of Exchangeable
         Shares upon exercise of the Share Redemption Right and shall cause to
         be listed and posted for trading (or the functional equivalent thereof)
         such Exchangeable Shares on the TSE.

(9)      The Corporation shall from time to time promptly advise the Trustee in
         writing of, and pay, or make provision satisfactory to the Trustee for
         the payment of, all taxes and charges which may be imposed by the laws
         of Canada or any province thereof (except income tax, capital gains
         tax, withholding tax or security transfer tax, if any) which shall be
         payable with respect to the issuance or delivery of Exchangeable Shares
         to Holders upon exercise of the Share Redemption Right pursuant to the
         terms of the Debentures and of this Indenture.

(10)     If the Corporation elects to satisfy its obligation to pay the
         Redemption Amount by delivering Exchangeable Shares in accordance with
         this Section 3.6 and if the Redemption Amount (or any portion thereof)
         to which a Holder is entitled is subject to withholding taxes, the
         Corporation, for the account of the Holder, shall sell, or cause to be
         sold, through investment banks, brokers or dealers selected by the
         Corporation, out of the Exchangeable Shares issued by the Corporation
         for this purpose, such number of Exchangeable Shares that is sufficient
         to yield net proceeds (after payment of all costs) to cover the amount
         of taxes required to be withheld, and shall remit the same, or cause
         same to be remitted on behalf of the Corporation, to the proper tax
         authorities within the period of time prescribed for this purpose under
         applicable laws.

SECTION 3.7 FAILURE TO SURRENDER DEBENTURES CALLED FOR REDEMPTION.

         If the Holder of any Debentures called for redemption in accordance
with Section 3.3 should, within 30 days from the Redemption Date, fail to
surrender any of such Debentures or fail within such time to (i) accept cash or
Exchangeable Shares, as the case may be, in satisfaction of the Redemption
Amount payable in respect thereof; or (ii) give such receipt therefor, if any,
as the Trustee may require, such cash or Exchangeable Shares, as the case may
be, shall be set aside in trust for such Holder, in accordance with Article 10
and Section 14.3, and such setting aside shall for all purposes be deemed a
payment to such Holder of the cash or Exchangeable Shares so set aside, and to
that extent, such Debentures shall thereafter not be considered as outstanding
hereunder and such Holder shall have no right, as of the Redemption Date, except
to


<PAGE>   30
                                      -24-


receive payment out of the cash or Exchangeable Shares so deposited (or, after
redemption or purchase of the Exchangeable Shares pursuant to their terms or to
the terms of the Plan, AMVESCAP Ordinary Shares), upon surrender of its
Debentures, without interest thereon.

SECTION 3.8 PURCHASE OF DEBENTURES.

(1)      Provided that no Event of Default has occurred and is continuing, the
         Corporation may purchase all or any of the Debentures in the open
         market (which shall include purchase from or through an investment
         dealer or a firm holding membership on a Recognized Stock Exchange) or
         by tender or by private contract at any price, subject to compliance
         with Applicable Securities Legislation regarding issuer bid
         requirements.

(2)      If, upon an invitation for tenders, more Debentures than the
         Corporation is prepared to accept are tendered at the same lowest
         price, the Debentures to be purchased by the Corporation will be
         selected by the Trustee in such manner (which may include pro rata, by
         lot or by random selection by computer) as the Trustee may deem
         equitable, from the Debentures tendered by each tendering
         Debentureholder who tendered at such lowest price. For this purpose,
         the Trustee may make, and from time to time amend, regulations with
         respect to the manner in which Debentures may be so selected and
         regulations so made shall be valid and binding upon all
         Debentureholders and, notwithstanding the fact that, as a result
         thereof, one or more of such Debentures become subject to purchase in
         part only. The Holder of any Debenture of which a part only is
         purchased, upon surrender of such Debenture for payment, shall be
         entitled to receive, without expense to such Holder, a new Debenture
         for the unpurchased part so surrendered and the Trustee shall certify
         and deliver such new Debenture upon receipt of the Debenture so
         surrendered.

SECTION 3.9 CANCELLATION OF PURCHASED DEBENTURES.

         All Debentures redeemed or purchased in whole or in part pursuant to
this Article 3 shall be forthwith delivered to and cancelled by the Trustee and
may not be reissued or resold and no Debentures shall be issued in substitution
therefor.

                                    ARTICLE 4
                      CONVERSION AND SHARE REPAYMENT RIGHT

SECTION 4.1 CONVERSION RIGHT.

(1)      Each Holder shall have the right, at its option, at any time and from
         time to time, to convert as of and with effect on the date specified by
         such Holder in its Conversion Notice (such date a "CONVERSION DATE"),
         which date shall be not less than four Business Days and not more than
         15 Business Days from the


<PAGE>   31
                                      -25-


         day the Trustee receives such Conversion Notice, each $1,000 principal
         amount of its Debentures into that number of Exchangeable Shares equal
         to the Conversion Number in effect on the date of the Conversion
         Notice, all on the terms and subject to the conditions provided in this
         Article 4. For greater certainty, the date of the Conversion Notice is
         (and shall be deemed to be) the date the Holder delivers such
         Conversion Notice to the Trustee (subject to Section 4.1(2)) as opposed
         to the Conversion Date (which date shall be a later date specified as
         aforesaid in such Conversion Notice).

(2)      In order to exercise the right to convert provided pursuant to Section
         4.1(1), the Holder will be required to deliver to the Trustee, at the
         place at which the register is maintained pursuant to Section 2.9, a
         conversion notice (the "CONVERSION NOTICE") in the form set forth in
         Schedule "C" hereto duly completed and executed by the Holder or its
         executors or administrators or other legal representatives or its or
         their attorney duly appointed by instrument in form and execution
         satisfactory to the Trustee, together with the related Debentures. The
         Trustee shall provide a copy of each Conversion Notice that it receives
         to the Corporation as soon as reasonably practicable and in any event
         by 5:00 p.m. (in the place at which the register is maintained pursuant
         to Section 2.9) on the Business Day immediately following the Business
         Day on which such notice is received by the Trustee. A Conversion
         Notice received by the Trustee after 4:30 p.m. (in the place at which
         the register is maintained pursuant to Section 2.9) on any day shall be
         deemed to have been received by the Trustee on the first Business Day
         after such day.

(3)      The Conversion Notice shall specify the principal amount of Debentures
         to be converted (to be not more than the aggregate principal amount of
         the Debentures delivered to the Trustee), provided that Debentures may
         only be converted in respect of principal amounts of $1,000 and
         integral multiples thereof.

(4)      On each Conversion Date, provided that it has not elected to pay the
         Conversion Value in cash pursuant to Section 4.2, the Corporation shall
         ensure that the following conditions are met:

         (a)      The qualification of the Exchangeable Shares to be issued on
                  conversion as Freely Tradeable;

         (b)      The listing (or the functional equivalent thereof) of such
                  additional Exchangeable Shares on the TSE;

         (c)      The Corporation being a reporting issuer (or its equivalent)
                  in good standing under Applicable Securities Legislation where
                  the distribution of such Exchangeable Shares occurs and where
                  such legislation recognizes the status of a reporting issue
                  (or its equivalent);


<PAGE>   32
                                      -26-


         (d)      No Event of Default shall have occurred and be continuing; and

         (e)      The receipt by the Trustee of an Officers' Certificate stating
                  that conditions (a), (b), (c) and (d) above have been
                  satisfied and setting forth the number of Exchangeable Shares
                  to be delivered for each $1,000 principal amount of Debentures
                  and the calculation of the Conversion Number as of the date of
                  the applicable Conversion Notice.

         If the foregoing conditions are not satisfied prior to the close of
         business (in the City of Toronto, Ontario) on such Conversion Date, the
         Corporation shall pay in cash the Conversion Value of the Debentures to
         be converted on such Conversion Date, together with such other amounts
         as are contemplated and payable in accordance with Section 4.4 (less
         any tax required by law to be deducted), unless the Holder of such
         Debenture waives the conditions which are not satisfied.

(5)      If a Holder has elected to convert Debentures in accordance with this
         Section 4.1 and if the Conversion Value (or any portion thereof) to
         which a Holder is entitled is subject to withholding taxes, the
         Corporation, for the account of the Holder, shall sell, or cause to be
         sold, through investment banks, brokers or dealers selected by the
         Corporation, out of the Exchangeable Shares issued by the Corporation
         pursuant to this Section 4.1, such number of Exchangeable Shares that
         is sufficient to yield net proceeds (after payment of all costs) to
         cover the amount of taxes required to be withheld, and shall remit
         same, or cause same to be remitted on behalf of the Corporation, to the
         proper tax authorities within the period of time prescribed for this
         purpose under applicable laws.

SECTION 4.2 RIGHT TO PAY CONVERSION VALUE IN CASH IN LIEU OF CONVERSION.

(1)      If a Holder elects to convert its Debentures on a Conversion Date, the
         Corporation shall have the right to elect to pay such Holder, in lieu
         of delivering Exchangeable Shares on conversion, the Conversion Value
         (as of the date of the applicable Conversion Notice) for each $1,000
         principal amount of Debentures tendered for conversion, together with
         such other amounts as are contemplated and payable in accordance with
         Section 4.4, in cash in lawful money of Canada (less any tax required
         by law to be deducted).

(2)      Without limiting the rights of the Corporation pursuant to Section 4.3,
         the Corporation shall exercise its right pursuant to Section 4.2(1) by
         notifying the Trustee and the Holder as soon as reasonably practicable
         (and in any event by transmitting such notice to the Trustee by
         facsimile or other means of electronic communication by 5:00 p.m.
         (London, England time) on the second Business Day after receipt by the
         Corporation of the applicable Conversion Notice and by depositing such
         notice, addressed to the Holder, in the mail or with a courier on or
         before the third Business Day after receipt by the Corporation of the


<PAGE>   33
                                      -27-


         applicable Conversion Notice) that the Corporation elects to pay the
         Conversion Value in cash to such Holder in lieu of delivering
         Exchangeable Shares on conversion. If the Corporation determines not to
         exercise its right pursuant to Section 4.2(1) it shall so advise the
         Trustee as soon as reasonably practicable (and in any event by
         transmitting such notice to the Trustee by facsimile or other means of
         electronic communication by 5:00 p.m. (London, England time) on the
         second Business Day after receipt by the Corporation of the applicable
         Conversion Notice. If no notice is transmitted to the Trustee pursuant
         to this Section 4.2(2) by 5:00 p.m. (London, England time) on the
         second Business Day following the receipt by the Corporation of the
         applicable Conversion Notice, the Corporation shall be deemed to have
         notified the Trustee that it has not elected to exercise its right
         pursuant to Section 4.2(1). After the Trustee has received any such
         notice from the Corporation (or been deemed to have been so notified),
         the Trustee shall respond to any inquiries it receives from such Holder
         concerning whether or not the Corporation has elected to pay the
         Conversion Value in cash.

SECTION 4.3 RIGHT TO REPAY PRINCIPAL AMOUNT IN EXCHANGEABLE SHARES ON MATURITY.

(1)      The Corporation shall have the right to elect to satisfy the obligation
         to repay on the Maturity Date the principal amount of all, but not less
         than all, of the Debentures outstanding by delivering to the Trustee,
         for each $1,000 principal amount of the Debentures, that number of
         Freely Tradeable Exchangeable Shares equal to the number obtained by
         dividing $1,000 by 95% of the Current Market Price on the Maturity Date
         (the "SHARE REPAYMENT RIGHT").

(2)      The Corporation shall send to the Debentureholders in the manner
         provided in Section 2.16, at least 10 Business Days and not more than
         20 Business Days prior to the Maturity Date, a notice (the "MATURITY
         NOTICE") in the form set forth in Schedule "D-1" hereto together with
         an exercise notice (an "EXERCISE NOTICE") in the form set forth in
         Schedule "D-2" hereto. The Maturity Notice will provide
         Debentureholders with the following options:

         (a)      to convert their Debentures to Exchangeable Shares, only if
                  the AMVESCAP Share Value on the Maturity Date is greater than
                  or equal to $1,000, subject to the right of the Corporation to
                  pay the Conversion Value in cash;

         (b)      to convert their Debentures to Exchangeable Shares, whether or
                  not the AMVESCAP Share Value on the Maturity Date exceeds
                  $1,000, subject to the right of the Corporation to pay the
                  Conversion Value in cash; or

         (c)      to receive payment of the principal amount of the Debentures
                  in cash, subject to exercise by the Corporation of the Share
                  Repayment Right;


<PAGE>   34
                                      -28-


         it being understood, in each case, that all accrued interest, if any,
         shall be paid in cash.

(3)      In order to select an option provided pursuant to Section 4.3(2),
         Debentureholders will be required to deliver to the Trustee at any
         place at which the register is maintained pursuant to Section 2.9 or
         any other place specified in the Maturity Notice before the
         Determination Date an Exercise Notice duly completed and executed by
         the Holder or its executors or administrators or other legal
         representatives or its or their attorney duly appointed by instrument
         in form and execution satisfactory to the Trustee, together with the
         related Debentures. A Debentureholder who does not deliver a duly
         completed Exercise Notice at or before the close of business (in the
         City of Toronto, Ontario) on the Determination Date will be deemed to
         have selected option (a) set out in Section 4.3(2) and the Debentures
         held by such Holders will automatically be converted into Exchangeable
         Shares, subject to the right of the Corporation to pay the Conversion
         Value in cash, if the AMVESCAP Share Value on the Maturity Date is
         greater than or equal to $1,000.

(4)      The Corporation shall specify in the Maturity Notice whether it will
         deliver Exchangeable Shares on conversion of the Debentures or, in lieu
         of delivering Exchangeable Shares on conversion, it elects to pay the
         Conversion Value in cash (less any tax required by law to be deducted)
         and whether, if a Holder selects option (c) set out in Section 4.3(2),
         the Corporation will, in lieu of paying cash on maturity, exercise the
         Share Repayment Right and deliver Exchangeable Shares to such Holder.
         If a Holder selects option (c) set out in Section 4.3(2) and the
         Corporation does not exercise the Share Repayment Right, the
         Corporation shall pay to such Holder the principal amount of its
         Debentures in cash on the Maturity Date.

(5)      The Trustee shall, on the Business Day immediately following the
         Determination Date, deliver written notice to the Corporation of the
         aggregate principal amount of Debentures which Holders have elected or
         are deemed to have elected to convert.

(6)      On the Business Day preceding the Maturity Date, if any Debentureholder
         selects (or is deemed to have selected) option (a) or option (b) set
         out in Section 4.3(2) and the Corporation has not exercised its right
         to pay the Conversion Value in cash, or if the Corporation has
         exercised the Share Repayment Right, the Corporation shall ensure that
         the following conditions are met:

         (a)      The qualification of the Exchangeable Shares to be issued on
                  conversion or pursuant to the Share Repayment Right as Freely
                  Tradeable;


<PAGE>   35
                                      -29-


         (b)      The listing (or the functional equivalent thereof) of such
                  additional Exchangeable Shares on the TSE;

         (c)      The Corporation being a reporting issuer (or its equivalent)
                  in good standing under Applicable Securities Legislation where
                  the distribution of such Exchangeable Shares occurs and where
                  such legislation recognizes the status of a reporting issuer
                  (or its equivalent);

         (d)      No Event of Default shall have occurred and be continuing;

         (e)      The receipt by the Trustee of an Officers' Certificate stating
                  that conditions (a), (b), (c) and (d) above have been
                  satisfied and setting forth the number of Exchangeable Shares
                  to be delivered for each $1,000 principal amount of Debentures
                  and the calculation of the Conversion Number; and

         (f)      The receipt by the Trustee of an Opinion of Counsel to the
                  effect that such Exchangeable Shares have been duly authorized
                  and, when issued and delivered pursuant to the terms of this
                  Indenture, will be validly issued as fully paid and
                  non-assessable and, that conditions (a) and (b) above have
                  been satisfied and that, relying exclusively on certificates
                  of good standing issued by the relevant securities
                  authorities, condition (c) above is satisfied, except that
                  such opinion in respect of condition (c) need not be expressed
                  with respect to those provinces where certificates of good
                  standing are not issued by the securities authorities.

         If the foregoing conditions are not satisfied prior to the close of
         business (in the City of Toronto, Ontario) on the Business Day
         preceding the Maturity Date, the Corporation shall pay in cash the
         Conversion Value of the Debentures held by any such Debentureholder
         together with all interest on such Debentures accrued to, but
         excluding, the Maturity Date (less any tax required by law to be
         deducted), unless the Debentureholder waives the conditions which are
         not satisfied.

(7)      In the event that the Corporation exercises its Share Repayment Right,
         or a Debentureholder selects (or is deemed to have selected) option (a)
         or option (b) set out in Section 4.3(2) and the Corporation has not
         exercised its right to pay the Conversion Value in cash, upon
         presentation and surrender of the Debenture for payment on maturity at
         the place where the register is maintained pursuant to Section 2.9 or
         any other place specified in the Maturity Notice, the Corporation shall
         (i) pay or cause to be paid in cash to the Holder thereof all accrued
         and unpaid interest to the Maturity Date and the cash equivalent
         contemplated for fractional shares in Section 4.5, if any, in each case
         less any tax required by law to be deducted; and (ii) deliver or cause
         to be delivered to the Holder thereof,


<PAGE>   36
                                      -30-


         certificates representing the Freely Tradeable Exchangeable Shares to
         which such Holder is entitled.

(8)      If the repayment by delivery of Exchangeable Shares (or any portion
         thereof) to which a Holder is entitled pursuant to this Section 4.3 or
         the conversion of Debentures into Exchangeable Shares pursuant to
         option (a) or option (b) set out in Section 4.3(2) is subject to
         withholding taxes, the Corporation, for the account of the Holder,
         shall sell, or cause to be sold, through investment banks, brokers or
         dealers selected by the Corporation, out of the Exchangeable Shares
         issued by the Corporation pursuant to this Section 4.3, such number of
         Exchangeable Shares that is sufficient to yield net proceeds (after
         payment of all costs) to cover the amount of taxes required to be
         withheld, and shall remit same, or cause same to be remitted on behalf
         of the Corporation, to the proper tax authorities within the period of
         time prescribed for this purpose under applicable laws.

SECTION 4.4 COMPLETION OF CONVERSION.

(1)      As soon as reasonably practicable but in any event on or prior to the
         fifth Business Day after each Conversion Date, the Corporation and/or
         the Trustee shall send by first class mail, postage prepaid, to each
         Holder who has elected to convert its Debentures pursuant to Section
         4.1 on such Conversion Date: (a) a cheque for the Conversion Value of
         each $1,000 principal amount of Debentures which such Holder has
         elected to convert together with interest on such Conversion Value at
         the rate of 6.00% per annum for the period from and including the
         Business Day immediately after such Conversion Date to but excluding
         the day such cheque is deposited in the mail, provided that the
         Corporation has exercised its right pursuant to Section 4.2, or
         certificates for the Exchangeable Shares to which such Holder is
         entitled provided that such Debentureholder has not completed the
         Retraction Request forming part of the Conversion Notice; (b) a cheque
         for interest accrued on such Debentures from the last date to which
         interest has been paid on such Debentures to but excluding the
         Conversion Date; (c) a cheque for the cash equivalent for any
         fractional Exchangeable Share contemplated by Section 4.5 to which such
         Holder is entitled; and (d) if such Holder has elected to convert a
         principal amount of Debentures (the "EXERCISED AMOUNT") which is less
         than the principal amount of the Debentures delivered by such Holder to
         the Trustee with the Holder's Conversion Notice (the "REGISTERED
         AMOUNT"), Debenture(s) registered in the name of such Holder in an
         aggregate principal amount equal to the amount by which the registered
         amount exceeds the exercised amount, less in all cases any tax required
         by law to be deducted.

(2)      All Debentures converted in whole or in part shall be delivered to and
         cancelled by the Trustee in accordance with Article 10 and the Trustee
         shall amend the register maintained by it pursuant to Section 2.9
         accordingly.


<PAGE>   37
                                      -31-


(3)      The Corporation shall provide to the Trustee the certificates for the
         Exchangeable Shares and for the Debentures to be delivered pursuant to
         Section 4.4(1), if any, and pay to the Trustee sufficient funds, by
         certified cheque, bank draft or wire transfer, in a timely manner, to
         permit the Trustee to fulfil its obligations under Section 4.4(1) and
         to make the payments, if any, required by Section 4.2 and Section 4.5.

SECTION 4.5 FRACTIONAL SHARES.

         No fractional Exchangeable Shares shall be delivered upon the
conversion of Debentures or exercise of the Share Repayment Right but, in lieu
thereof, the Corporation shall pay, or cause to be paid, to a Debentureholder
who would otherwise be entitled to a fractional Exchangeable Share the cash
equivalent thereof (determined on the basis of the Current Market Price on the
date of the Conversion Notice or the Maturity Date, as applicable), less any tax
required by law to be deducted.

SECTION 4.6 RELATING TO THE ISSUE OF EXCHANGEABLE SHARES.

(1)      A Holder shall be treated as the shareholder of record of the
         Exchangeable Shares issued on due conversion of its Debentures or due
         exercise by the Corporation of the Share Repayment Right, and the
         issuance of Exchangeable Shares shall be deemed to have occurred for
         all purposes effective immediately after the close of business (in the
         City of Toronto, Ontario) on the Conversion Date, in the case of a
         conversion pursuant to Section 4.1 or on the Maturity Date, in the case
         of the exercise of the Share Repayment Right pursuant to Section 4.3,
         and such Holder shall be entitled to all substitutions therefor, all
         income earned thereon or accretions thereto and all dividends or
         distributions (including stock dividends and dividends or distributions
         in kind) thereon and arising thereafter and in the event that the
         Trustee receives the same, it shall hold the same in trust for the
         benefit of such Holder.

(2)      The Corporation shall at all times reserve and keep available out of
         its authorized Exchangeable Shares (if the number thereof is or becomes
         limited) solely for the purpose of issue and delivery upon the
         conversion of Debentures or the exercise of the Share Repayment Right
         as provided herein, and shall issue to Debentureholders who may
         exercise their conversion rights hereunder or to whom Exchangeable
         Shares shall be issued pursuant to exercise of the Share Repayment
         Right, such number of Exchangeable Shares as shall be issuable in such
         events. All Exchangeable Shares which shall be so issued shall be duly
         and validly issued as fully paid and non-assessable.

(3)      The Corporation shall comply with all Applicable Securities Legislation
         regulating the issue and delivery of Exchangeable Shares upon
         conversion of Debentures or exercise of the Share Repayment Right and
         shall cause to be listed


<PAGE>   38
                                      -32-


         and posted for trading (or the function equivalent thereof) such
         Exchangeable Shares on the TSE.

SECTION 4.7 TAXES AND CHARGES ON THE ISSUE OF EXCHANGEABLE SHARES.

         The Corporation shall from time to time promptly advise the Trustee in
writing of, and pay, or make provision satisfactory to the Trustee for the
payment of, all taxes and charges which may be imposed by the laws of Canada or
any province thereof (except income tax, capital gains tax, withholding tax or
security transfer tax, if any) and which shall be payable with respect to the
issuance or delivery of Exchangeable Shares to Holders upon the conversion of
Debentures or exercise of the Share Repayment Right pursuant to the terms of the
Debentures and this Indenture.

                                    ARTICLE 5
                                   ADJUSTMENTS

SECTION 5.1 ADJUSTMENT UPON SUBDIVISION OR CONSOLIDATION.

         If and whenever at any time after the date hereof, the outstanding
Exchangeable Shares are subdivided or redivided into a greater number of
Exchangeable Shares or are reduced, combined or consolidated into a smaller
number of Exchangeable Shares or upon a distribution of Exchangeable Shares to
all or substantially all holders of Exchangeable Shares by way of a stock
dividend or otherwise (other than an issue of shares to holders of Exchangeable
Shares who have elected to receive dividends in stock in lieu of receiving cash
dividends) (each such event being referred to in this section as a "CHANGE"),
the AMVESCAP Share Rate shall thereafter be adjusted to be equal to the number
of Exchangeable Shares which a holder of that number of Exchangeable Shares
equal to the AMVESCAP Share Rate (prior to such adjustment) would have been
entitled to receive as a result of such change on the effective date of such
change.

SECTION 5.2 REORGANIZATION EVENT.

         If and whenever at any time after the date hereof there shall occur any
Reorganization Event, the AMVESCAP Share Rate and/or the definition of Current
Market Price shall be adjusted or revised, respectively, by the board of
directors of the Guarantor, subject to the prior consent of the Recognized Stock
Exchange on which the Exchangeable Shares are listed, if such consent is
required, in such manner as the board of directors of the Guarantor may in their
sole discretion determine to be fair and equitable in the circumstances to the
Holders, which determination shall be conclusive, and such adjustment shall be
effective as of the effective date of such Reorganization Event.


<PAGE>   39
                                      -33-


SECTION 5.3 ADJUSTMENTS AS A RESULT OF CERTAIN DISTRIBUTIONS AND EXTRAORDINARY
            CASH DIVIDENDS.

(1)      If and whenever at any time after the date hereof, the Corporation
         shall (i) make a distribution of Distributed Property to all or
         substantially all holders of the Exchangeable Shares or (ii) issue
         options, rights or warrants to all or substantially all holders of the
         Exchangeable Shares entitling them to acquire Exchangeable Shares or
         other securities convertible into, or exchangeable for, Exchangeable
         Shares at less than 95% of the Current Market Price prevailing at the
         time of such issue, then the AMVESCAP Share Rate shall thereafter be
         equal to:

                                      1000
                                     -------
                                     (A - B)

         where:

         A equals 1,000 divided by the AMVESCAP Share Rate in effect immediately
         prior to the distribution or issue; and

         B is a number equal to the value of the Distributed Property, or the
         value of such options, rights or warrants, in respect of each
         Exchangeable Share as determined by the Directors, acting reasonably,
         which determination shall be conclusive provided, however, that for
         purposes of this Section 5.3(1) the value of any such rights shall be
         deemed to be zero if at the time the Corporation issues such rights:

         (a)      the Corporation issues to each Debentureholder the number of
                  such rights such Debentureholder would have been entitled to
                  receive if such Debentureholder had converted its Debentures
                  into Exchangeable Shares on the record date for the issue of
                  such rights, provided that, if as a result of the issuance of
                  such rights to a Debentureholder there would be a requirement
                  to file a registration statement with the Securities and
                  Exchange Commission in the United States or a similar document
                  in any other jurisdiction or ongoing disclosure or other
                  requirements in the United States or in any other
                  jurisdiction, the Corporation shall not issue any such rights
                  to such Debentureholder but in lieu of the rights such
                  Debentureholder would otherwise be entitled to receive, such
                  Debentureholder shall be entitled to receive a cash payment
                  equal to the net proceeds (after expenses) received by or on
                  behalf of the Corporation upon the sale of such rights and
                  promptly after the issuance of such rights, the Corporation
                  shall sell such rights or shall cause such rights to be sold;
                  and

         (b)      such rights are listed (or the functional equivalent thereof)
                  on the TSE.


<PAGE>   40
                                      -34-


(2)      If and whenever at any time after the date hereof payment of a cash
         dividend by the Corporation results in an Extraordinary Cash Dividend
         in respect of the calendar year in which the dividend was paid, the
         AMVESCAP Share Rate shall thereafter be equal to:

                                      1000
                                     -------
                                     (A - B)

         where:

         A equals 1,000 divided by the AMVESCAP Share Rate in effect immediately
         prior to the payment of the Extraordinary Cash Dividend; and

         B is a number equal to the amount of the Extraordinary Cash Dividend in
         respect of each Exchangeable Share.

SECTION 5.4 DISCRETIONARY ADJUSTMENT.

         In case the Corporation after the date hereof shall take any action
affecting, or relating to, the Exchangeable Shares, other than any action
described in Section 5.1 or Section 5.3 which in the opinion of the Directors
would prejudicially affect the rights of Holders upon conversion, the AMVESCAP
Share Rate shall be adjusted by the Directors, subject to the prior consent of
the Recognized Stock Exchange on which the Exchangeable Shares are listed, if
such consent is required, in such manner, if any, and at such time, as they may
in their sole discretion determine to be fair and equitable in the circumstances
to the Holders, which determination shall be conclusive. Failure of the
Directors to take action so as to provide for an adjustment on or prior to the
effective date of any action by the Corporation affecting the Exchangeable
Shares shall be conclusive evidence that the Directors have determined that it
is fair and equitable to make no adjustment in the circumstances.

SECTION 5.5 CHANGES AFFECTING EXCHANGEABLE SHARES.

         If and whenever at any time after the date hereof there shall be a
reclassification or redemption of Exchangeable Shares (other than a subdivision,
redivision, reduction, combination or consolidation), a change of Exchangeable
Shares into other shares or into other securities, a consolidation,
amalgamation, merger, reorganization or arrangement of the Corporation with or
into any other corporation or other entity (other than a consolidation,
amalgamation, merger, reorganization or arrangement which does not result in a
re-classification or change of the outstanding Exchangeable Shares) (any such
event being herein called a "CAPITAL REORGANIZATION"), then notwithstanding any
other provision of this Indenture, after the effective date of such Capital
Reorganization any Holder who is entitled to receive Exchangeable Shares as a
result of the exercise by the Holder after such date of its conversion right or
the exercise by the Corporation after such date of the Share Redemption Right or
the Share Repayment Right shall be entitled to receive and shall accept, in lieu
of Exchangeable Shares, such other shares or


<PAGE>   41
                                      -35-


securities or other property which such Holder would have been entitled to
receive as a result of such Capital Reorganization if, on the effective date
thereof, the Holder had been the registered holder of Exchangeable Shares. After
the effective date of such Capital Reorganization, the other provisions of this
Indenture including, without limitation, Section 3.6, Section 4.1 and Section
4.3, shall be revised to the extent necessary, as determined by the Directors in
their sole discretion, which determination shall be conclusive, to give effect
to the foregoing provisions of this Section 5.5.

SECTION 5.6 RULES APPLICABLE TO ADJUSTMENTS.

(1)      The adjustments provided for in Section 5.1 and Section 5.3 shall be
         cumulative and all adjustments provided for in Article 5 shall be made
         successively. Notwithstanding the foregoing, (i) no adjustment to the
         calculation of the AMVESCAP Share Rate will be required, unless the
         cumulative effect of such adjustment would result in a change of at
         least 1.00% to such rate and (ii) there will be no adjustment of the
         AMVESCAP Share Rate in respect of any event described in Section 5.3(1)
         if the Debentureholders are allowed to participate as though they had
         converted their Debentures prior to the applicable record date or
         effective date, subject to the approval of any Recognized Stock
         Exchange on which the Exchangeable Shares are listed.

(2)      If a dispute shall at any time arise with respect to the adjustments
         provided for in this Article 5, such dispute shall be conclusively
         determined by the Directors, subject to the prior consent of the
         Recognized Stock Exchange on which the Exchangeable Shares are listed,
         if required, and any such determination shall be binding upon the
         Corporation, the Guarantor, the Trustee and the Holders.

(3)      If necessary and determined appropriate by the Directors, appropriate
         adjustments shall be made by the Directors in the application of the
         provisions set forth in this Article 5 with respect to the rights and
         interest thereafter of Holders so that the adjustments as set forth in
         this Article 5 shall thereafter correspondingly be made in relation to
         any shares, other securities or other property thereafter deliverable
         upon conversion of Debentures.

(4)      The Corporation shall from time to time immediately after the
         occurrence of any event which requires an adjustment in the AMVESCAP
         Share Rate or the occurrence of a Reorganization Event or a Capital
         Reorganization provide to the Trustee an Officers' Certificate
         specifying the nature of such event and the impact thereof on the terms
         of the Debentures and setting forth in reasonable detail the method of
         calculation of any adjustment.

SECTION 5.7 NOTICE OF SPECIAL EVENTS.

         The Corporation shall give notice to the Debentureholders in the manner
provided in Section 2.16 as soon as practicable and in any event within 10
Business


<PAGE>   42
                                      -36-


Days following the occurrence of any event referred to in Section 5.6(4) and
such notice shall specify the particulars of such event and any resulting
adjustments to be made in the terms of the Debentures. Contemporaneously with
the giving of such notice, the Corporation shall issue a press release over a
newswire service in Canada and the United Kingdom advising Debentureholders of
the occurrence of such event and the particulars thereof and any resulting
adjustments to be made in the terms of the Debentures.

                                    ARTICLE 6
                           SUBORDINATION OF DEBENTURES

SECTION 6.1 AGREEMENT TO SUBORDINATE.

         Each Debentureholder, by its acceptance thereof, acknowledges and
agrees, that the payment of all amounts owing hereunder or under the Debentures
is hereby expressly subordinated and postponed, to the extent and in the manner
hereinafter set forth, in right of payment to the prior payment in full of all
Senior Liabilities. Without prejudice to the rights of any other holder of
Senior Liabilities not having done so, the benefit of this Article 6 and of any
other provision hereof and of the Debentures relating to the subordination and
postponement thereof may be accepted at any time by or on behalf of any holder
of Senior Liabilities by written notice to the Trustee.

SECTION 6.2 DISTRIBUTION ON INSOLVENCY OR WINDING-UP.

         In the event of any insolvency or bankruptcy proceedings, or any
receivership, liquidation, reorganization or other similar proceedings relative
to the Corporation or the Guarantor, or to the property or assets of the
Corporation or the Guarantor, or in the event of any proceedings for voluntary
liquidation, dissolution or other winding-up of the Corporation or the
Guarantor:

         (a)      The holders of all Senior Liabilities will first be entitled
                  to receive payment in full of all amounts payable under the
                  Senior Liabilities, before the Debentureholders will be
                  entitled to receive any payment or distribution of any kind or
                  character, whether in cash, property or securities, which may
                  be payable or deliverable in any such event in respect of any
                  of the Debentures;

         (b)      Any payment by, or distribution of assets of, the Corporation
                  or the Guarantor of any kind or character, whether in cash,
                  property or securities (other than securities of the
                  Corporation or the Guarantor or any other corporation provided
                  for by a plan of reorganization or readjustment the payment of
                  which is subordinate, at least to the extent provided in this
                  Article 6 with respect to the Debentures, to the payment of
                  all Senior Liabilities, provided that (i) the Senior
                  Liabilities are assumed by the new corporation(s), if any,
                  resulting from such reorganization or readjustment


<PAGE>   43
                                      -37-


                  and (ii) without prejudice to the rights of such holders with
                  respect to any such plan (including without limitation as to
                  whether or not to approve same and on what conditions to do
                  so), the rights of the holders of Senior Liabilities are not
                  altered adversely by such reorganization or readjustment) to
                  which the Debentureholders or the Trustee would be entitled,
                  except for the provisions of this Article 6, will be paid or
                  delivered by the Person making such payment or distribution,
                  whether a trustee in bankruptcy, a receiver, a
                  receiver-manager, a liquidator or otherwise, directly to the
                  holders of Senior Liabilities or their representative or
                  representatives or to the trustee or trustees under any
                  indenture under which any instruments evidencing any of such
                  Senior Liabilities may have been issued, subject to the terms
                  of such Senior Liabilities including, without limitation, the
                  ranking, if any, amongst such Senior Liabilities, rateably
                  according to the aggregate amounts remaining unpaid on account
                  of the Senior Liabilities held or represented by each, to the
                  extent necessary to make payment in full of all Senior
                  Liabilities remaining unpaid after giving effect to any
                  concurrent payment or distribution (or provision therefor) to
                  the holders of such Senior Liabilities; and

         (c)      Subject to Section 6.6, if, notwithstanding the foregoing, any
                  payment by, or distribution of assets of, the Corporation or
                  the Guarantor of any kind or character, whether in cash,
                  property or securities (other than securities of the
                  Corporation or the Guarantor or any other corporation provided
                  for by a plan of reorganization or readjustment the payment of
                  which is subordinate, at least to the extent provided in this
                  Article 6 with respect to the Debentures, to the payment of
                  all Senior Liabilities, provided that (i) the Senior
                  Liabilities are assumed by the new corporation(s), if any,
                  resulting from such reorganization or readjustment and (ii)
                  without prejudice to the rights of such holders with respect
                  to any such plan (including without limitation as to whether
                  or not to approve same and on what conditions to do so), the
                  rights of the holders of Senior Liabilities are not altered
                  adversely by such reorganization or readjustment), is received
                  by the Trustee or the Debentureholders before all Senior
                  Liabilities are paid in full, such payment or distribution
                  will be held in trust for the benefit of and, subject to the
                  terms of such Senior Liabilities including, without
                  limitation, the ranking, if any, amongst such Senior
                  Liabilities, will be paid over to the holders of such Senior
                  Liabilities or their representative or representatives or to
                  the trustee or trustees under any indenture under which any
                  instruments evidencing any of such Senior Liabilities may have
                  been issued, rateably as aforesaid, for application to the
                  payment of all Senior Liabilities remaining unpaid until such
                  Senior Liabilities have been paid in full, after giving effect
                  to any concurrent


<PAGE>   44
                                      -38-


                  payment or distribution (or provision therefor) to the holders
                  of such Senior Liabilities.

SECTION 6.3 SUBROGATION OF DEBENTURES.

         Subject to the prior payment in full of all Senior Liabilities, the
Debentureholders shall be subrogated to the rights of the holders of Senior
Liabilities to receive payments and distributions of assets of the Corporation
or the Guarantor in respect of and on account of Senior Liabilities, to the
extent of the application thereto of moneys or other assets which would have
been received by the Debentureholders, but for the provisions of this Article 6,
until the principal of and interest and all other amounts owing on the
Debentures and under this Indenture shall be paid in full. No payment or
distribution of assets of the Corporation or the Guarantor to the
Debentureholders which would be payable or distributable to the holders of
Senior Liabilities pursuant to this Article 6 shall, as between the Corporation,
the Guarantor, their creditors (other than the holders of Senior Liabilities)
and the Debentureholders, be deemed to be a payment by the Corporation or the
Guarantor to or on account of the Debentureholders, it being understood that the
provisions of this Article 6 are, and are intended, solely for the purpose of
defining the relative rights of the Debentureholders, on the one hand, and the
holders of the Senior Liabilities, on the other hand. Nothing contained in this
Article 6 or elsewhere in this Indenture or in the Debentures is intended to or
shall impair, as between the Corporation or the Guarantor and their respective
creditors (other than the holders of Senior Liabilities and the
Debentureholders), the obligation of the Corporation or the Guarantor, which is
unconditional and absolute, to pay to the Debentureholders the principal of and
interest on the Debentures, as and when the same shall become due and payable in
accordance with their terms, or to affect the relative rights of the
Debentureholders and the creditors of the Corporation, other than the holders of
the Senior Liabilities, nor shall anything herein or therein prevent the Trustee
or the Holder of any Debentures from exercising all remedies otherwise permitted
by applicable law upon default under this Indenture, subject to Article 9 and
the rights, if any, under this Article 6, of the holders of Senior Liabilities
upon the exercise of any such remedy.

SECTION 6.4 NO PAYMENT TO DEBENTUREHOLDERS IF EVENT OF DEFAULT UNDER THE SENIOR
            LIABILITIES.

(1)      Upon the maturity of any Senior Liabilities by lapse of time,
         acceleration or otherwise, then, except as hereinafter otherwise
         provided in Section 6.4(3), all amounts payable under such Senior
         Liabilities shall first be paid in full, or shall first have been duly
         provided for, before any payment on account of principal of or interest
         or any other amount owing on the Debentures or under this Indenture is
         made.

(2)      Except as hereinafter otherwise provided in Section 6.4(3), the
         Corporation and the Guarantor shall not make any payment, and the
         Debentureholders shall not


<PAGE>   45
                                      -39-


         be entitled to demand, institute proceedings for the collection of, or
         receive any payment or benefit (including without limitation by
         compensation, set-off, combination of accounts or realization of
         security or otherwise in any manner whatsoever) on account of the
         indebtedness represented by the Debentures (other than pursuant to the
         right of conversion) (i) in a manner inconsistent with the terms (as
         they exist on the date hereof) of this Indenture or of the Debentures,
         or (ii) at any time when a default or an event of default, as defined
         in any Senior Liabilities or any instrument evidencing the same and
         permitting, by the lapse of time or giving of notice, the holders
         thereof to accelerate the maturity thereof, has occurred under any
         Senior Liabilities and is continuing and notice of such default or
         event of default has been given by or on behalf of the holders of
         Senior Liabilities to the Corporation or the Guarantor, as the case may
         be, unless and until such Senior Liabilities have been paid and
         satisfied in full, or unless and until such default or event of default
         shall have been cured or waived or shall have ceased to exist in
         accordance with the provisions of such Senior Liabilities.

(3)      For greater certainty but without limiting the generality of the
         foregoing, this Section 6.4 shall not be construed so as to prevent the
         Trustee from receiving and retaining any payments on account of
         Debentures which are made (i) in a manner that is consistent with the
         terms of this Indenture or of the Debentures and (ii) at any time when
         no default or event of default, as defined in any Senior Liabilities or
         any instrument evidencing the same and permitting, by the lapse of time
         or giving of notice, the holders thereof to accelerate the maturity
         thereof, has occurred and is continuing and in respect of which notice
         has not been given by or on behalf of the holders of Senior Liabilities
         to the Corporation or the Guarantor.

SECTION 6.5 AUTHORIZATION OF DEBENTUREHOLDERS TO TRUSTEE TO EFFECT
            SUBORDINATION.

         Each Holder of Debentures, by its acceptance thereof, authorizes and
directs the Trustee, on its behalf, to take such action as may be necessary or
appropriate to effect the subordination and postponement provided for in this
Article 6 and appoints the Trustee its attorney-in-fact for any and all such
purposes.

SECTION 6.6 KNOWLEDGE OF TRUSTEE.

         Notwithstanding the provisions of this Article 6, the Trustee will not
be charged with knowledge of the existence of any facts that would prohibit the
making of any payment of moneys to or by the Trustee, or the taking of any other
action by the Trustee, unless and until the Trustee has received written notice
thereof from or on behalf of the Corporation, the Guarantor, any Debentureholder
or any holder or representative of any Senior Liabilities.


<PAGE>   46
                                      -40-


SECTION 6.7 TRUSTEE MAY HOLD SENIOR LIABILITIES.

         The Trustee is entitled to all the rights set forth in this Article 6
with respect to any Senior Liabilities at the time held by it, to the same
extent as any other holder of Senior Liabilities, and nothing in this Indenture
deprives the Trustee of any of its rights as such holder.

SECTION 6.8 RIGHTS OF HOLDERS OF SENIOR LIABILITIES NOT IMPAIRED.

         No right of any present or future holder of any Senior Liabilities to
enforce the subordination and postponement provided for in this Article 6 will
at any time or in any way be prejudiced or impaired by any act or failure to act
on the part of the Corporation or the Guarantor or by any non-compliance by the
Corporation or the Guarantor with the terms, provisions and covenants of this
Indenture, regardless of any knowledge thereof which any such holder may have or
be otherwise charged with.

SECTION 6.9 ALTERING THE SENIOR LIABILITIES.

         The holders of the Senior Liabilities have the right to extend, renew,
modify or amend the terms of the Senior Liabilities or any security therefor and
to release, sell or exchange such security and otherwise to deal freely with the
Corporation and the Guarantor, all without notice to or consent of the
Debentureholders or the Trustee and without affecting the liabilities and
obligations of the parties to this Indenture or the Debentureholders or the
subordination and postponement provided for in this Article 6.

SECTION 6.10 ADDITIONAL INDEBTEDNESS.

         This Indenture does not restrict the Corporation or the Guarantor from
incurring additional Indebtedness or mortgaging, pledging or charging its
properties to secure any Indebtedness.

SECTION 6.11 RIGHT OF DEBENTUREHOLDER TO CONVERT NOT IMPAIRED.

         The subordination of the Debentures to the Senior Liabilities and the
provisions of this Article 6 do not impair in any way the right of a
Debentureholder to convert its Debentures pursuant to Section 4.1.

                                    ARTICLE 7
                              GUARANTEE OF AMVESCAP

SECTION 7.1 GUARANTEE FOR BENEFIT OF ALL DEBENTUREHOLDERS

         The provisions of this Article 7 are for the benefit of, and the
Trustee shall hold all rights hereby conferred in trust for the equal and
rateable benefit of, all present and future Debentureholders.


<PAGE>   47
                                      -41-


SECTION 7.2 GUARANTEE OF PRINCIPAL, INTEREST AND OTHER AMOUNTS

         Subject to Article 6:

         (a)      The Guarantor agrees to be liable for and irrevocably and
                  unconditionally guarantees the full and prompt payment when
                  due (whether at stated maturity, by acceleration or otherwise)
                  and at all times thereafter, and performance, of all of the
                  obligations hereinafter owing to Debentureholders and the
                  Trustee by the Corporation pursuant to this Indenture and the
                  Debentures. The obligations of the Guarantor under this
                  Article 7 are primary, absolute and unconditional; and

         (b)      This guarantee by the Guarantor is a continuing guarantee of
                  payment and performance, in full, of the obligations of the
                  Corporation under this Indenture and the Debentures and not of
                  collection and is in no way conditional or contingent upon any
                  attempt to collect from the Corporation. The obligations of
                  the Guarantor under this Article 7 shall not be discharged
                  until payment and performance, in full, of the obligations of
                  the Corporation under this Indenture and the Debentures has
                  occurred and the Trustee has become obligated pursuant to
                  Section 10.4 to execute and deliver such deeds or other
                  instruments as shall be requisite to release the Corporation
                  and the Guarantor from the terms of this Indenture and the
                  Debentures, except those relating to the indemnification of
                  the Trustee. In the event of a default in payment of any
                  amounts owing under this Indenture or the Debentures or in
                  performance of any of the Corporation's obligations under this
                  Indenture or the Debentures, the Trustee (or any
                  Debentureholder when so permitted under this Indenture) may
                  institute legal proceedings directly against the Guarantor to
                  enforce this guarantee without proceeding against the
                  Corporation.

SECTION 7.3 THE GUARANTOR'S LIABILITY ON DISCHARGE OF THE CORPORATION

(1)      Subject to Article 6, in the event that:

         (a)      The Trustee, pursuant to Section 9.1, shall have declared the
                  principal of and interest on the Debentures then outstanding
                  and any other amounts payable under this Indenture to be due
                  and payable and that no part of or a portion only such
                  principal and interest or any other amounts payable under this
                  Indenture shall have been paid by or on behalf of the
                  Corporation and by operation of law the Corporation shall have
                  been discharged from all further liability under or in respect
                  of the Debentures;

         (b)      Pursuant to any compromise or arrangement, whether voluntary
                  or involuntary, between the Corporation and its creditors or
                  any of them, the


<PAGE>   48
                                      -42-


                  Debentures are cancelled or the terms thereof are modified, or
                  this Indenture terminated;

         (c)      In any other way, the Corporation is released from its
                  obligations under and with respect to the Debentures or any
                  amounts payable under this Indenture or any part thereof,

         then for all purposes hereof the Debentures and all amounts payable
         under this Indenture shall nevertheless be deemed to be still in
         existence and outstanding and the Guarantor shall, on the date of such
         discharge, cancellation, modification, termination or release, be
         primarily liable to make payment of interest (including interest on
         amounts in default) and principal on the Debentures and all other
         amounts payable under this Indenture in the same manner as though the
         Guarantor were a party to this Indenture in place of the Corporation
         and with primary liability hereunder but only to the extent that there
         are insufficient funds in the hands of the Trustee at such time to make
         such payment.

(2)      Subject to Article 6, for the purposes of the foregoing, the Guarantor
         shall pay as aforesaid to the Trustee, for the equal and rateable
         benefit of each and every Debentureholder, the amounts required to be
         paid on the dates provided for such payments under the provisions of
         this Indenture.

SECTION 7.4 LIABILITY OF THE GUARANTOR

(1)      The Guarantor agrees with the Trustee that, as among the Guarantor, the
         Debentureholders and the Trustee, the obligations of the Guarantor
         shall not be satisfied, reduced, affected or discharged by time being
         given, or any other forbearance whatsoever whether as to time of
         performance or otherwise, including, without limitation, the acceptance
         of any partial payment or performance of any obligations of the
         Corporation under this Indenture or the Debentures, or by any failure
         or delay in giving any notice required under this Indenture.

(2)      The Guarantor agrees that its obligations under this Article 7 shall
         not be affected or impaired by any act, omission, matter or thing
         whatsoever occurring before, upon or after any of the obligations of
         the Corporation under this Indenture or the Debentures become due and
         payable which might constitute a whole or partial defence to a claim
         against the Guarantor under this Article 7 or might operate to release
         or otherwise exonerate the Guarantor from any of its obligations under
         this Article 7 or otherwise affect such obligations.

(3)      The Trustee and the Debentureholders may, pursuant to the terms of this
         Indenture, modify, extend, renew, replace, amend, supplement, continue
         or alter any provisions of the Debentures or this Indenture and may
         deal with the


<PAGE>   49
                                      -43-


         Corporation, the Debentures and this Indenture without releasing,
         discharging, limiting or otherwise affecting in whole or in part the
         obligations of the Guarantor under this Article 7, without the consent
         of or notice to the Guarantor and, for greater certainty, the
         Debentureholders and the Trustee shall not be bound either to seek or
         exhaust their recourse against the Corporation or against any other
         Person or against the property of the Corporation or of any other
         Person before being entitled, subject to Article 6, to payment from the
         Guarantor.

SECTION 7.5 SUBROGATION

(1)      Any payment by or recovery from the Guarantor of any amounts payable by
         the Corporation under this Indenture shall not (except as between the
         Corporation and the Debentureholders and the Trustee and to the extent
         of any such payment) be taken to relieve the Corporation from liability
         for such payment, but such liability of the Corporation shall continue
         unimpaired as a liability enforceable by or on behalf of the Guarantor
         in respect thereof, and the Guarantor shall be subrogated pro tanto as
         against the Corporation to the rights, privileges and powers to which
         the Trustee and/or the Debentureholders were entitled prior to such
         payment by or on behalf of the Guarantor provided nevertheless that
         such rights of the Guarantor shall rank subsequent to and not pari
         passu with the rights of the Trustee and/or the Debentureholders
         hereunder. The Guarantor shall not, unless and until the whole of the
         principal amount of the Debentures and the interest thereon and all
         other amounts owing under this Indenture shall have been paid, be
         entitled to any rights or remedies in subrogation to the rights,
         privileges and powers of the Trustee and/or the Debentureholders as
         aforesaid.

(2)      Except as hereinbefore in this Section 7.5 expressly provided with
         respect to the rights of the Guarantor by way of subrogation to the
         rights, privileges and powers of the Trustee, nothing contained in this
         Section 7.5 shall or shall be deemed to restrict the recovery by the
         Guarantor at any time from the Corporation of any amounts that may have
         been paid by or on behalf of the Guarantor hereunder.

(3)      If the Trustee shall hold any assets for the benefit of the
         Debentureholders whether or not such assets are the property of the
         Corporation or if the Trustee shall be a party to any proceedings, or
         shall have any rights to institute any proceedings, for the benefit of
         the Debentureholders, whether against the Corporation or its property
         or otherwise, the Guarantor shall, at such time as the whole of the
         principal amount of the Debentures, the interest (including interest on
         amounts in default) thereon and all other amounts owing under this
         Indenture shall have been paid, be entitled to all such assets and
         rights and shall be subrogated to the rights, privileges and powers of
         the Trustee with respect thereto and with respect to any such
         proceedings.


<PAGE>   50
                                      -44-


SECTION 7.6 WAIVER

         The Guarantor hereby waives notice of acceptance of the guarantee
contained in this Article 7 and acknowledges that the guarantee, covenants and
agreements of the Guarantor herein contained and provided for shall take effect
and are hereby declared to be binding upon the Guarantor notwithstanding any
defect in or omission from this Indenture or the Debentures. The Guarantor
hereby unconditionally waives notice of any of the matters referred to in
Section 9.1, all notices which may be required by any statute, rule of law,
contract or otherwise to preserve any rights of the Trustee on behalf of any
Debentureholders against the Guarantor hereunder, including any right to the
enforcement, assertion or exercise of any right, remedy, power or privilege, and
any requirement of diligence on the part of the Trustee.

SECTION 7.7 WAIVER OF DEFAULT

         The Guarantor shall be deemed not to be in default hereunder if the
default of the Corporation in respect of which the Guarantor would otherwise be
or become liable hereunder shall have been waived or directed to be waived
pursuant to Section 9.2.

SECTION 7.8 ACKNOWLEDGEMENT

         The Guarantor acknowledges that the guarantee contained in this Article
7 is in addition to and not in substitution for any other guarantee(s) held or
that may hereafter be held by the Trustee.

SECTION 7.9 NOTICE TO GUARANTOR

         Any notices, demands and other communications to the Guarantor under
the provisions of this Article 7 shall be valid and effective if delivered in
accordance with Section 2.18 of this Indenture.

SECTION 7.10 NO SET-OFF RIGHTS

         The Guarantor shall not have the right to set-off against the
obligations of the Guarantor arising under this Article 7 any indebtedness or
obligations which may be at any time due and owing by the Trustee or the
Debentureholders to the Guarantor.

                                    ARTICLE 8
                 COVENANTS OF THE CORPORATION AND THE GUARANTOR

SECTION 8.1 COVENANTS OF THE CORPORATION.

         The Corporation covenants with the Trustee that so long as any of the
Debentures remain outstanding:

         (a)      It will continue to be a wholly-owned subsidiary of the
                  Guarantor;


<PAGE>   51
                                      -45-


         (b)      It will duly and punctually pay or cause to be paid to every
                  Debentureholder, or to the Trustee on behalf of every
                  Debentureholder, the principal thereof and any interest
                  accrued thereon, at the dates and places and in the manner
                  provided for herein and in the Debentures;

         (c)      Subject to its rights pursuant to Article 11, it will do or
                  cause to be done all things necessary to preserve and keep in
                  full force and effect its corporate existence, and will, if
                  and whenever required in writing by the Trustee, forthwith
                  file with the Trustee copies of all annual and periodic
                  reports of the Guarantor furnished to the Corporation's
                  shareholders after the date hereof, and at all reasonable
                  times it will furnish or cause to be furnished to the Trustee
                  or its duly authorized agent or attorney such information
                  relating to its business as the Trustee may reasonably
                  require;

         (d)      It will annually, within 120 days of the Corporation's fiscal
                  year end (and at any other reasonable time upon demand by the
                  Trustee), deliver to the Trustee an Officers' Certificate
                  confirming that it has complied with all requirements
                  contained in this Indenture that, if not complied with, would,
                  with the giving of notice, lapse of time or otherwise,
                  constitute an Event of Default, or, if there has been failure
                  to comply, giving particulars thereof;

         (e)      It will remain a reporting issuer (or its equivalent) in good
                  standing under Applicable Securities Legislation where the
                  distribution of Exchangeable Shares may occur in accordance
                  with the terms of this Indenture and the Debentures and where
                  such legislation recognizes the status of reporting issuer (or
                  its equivalent);

         (f)      In order to prevent any accumulation after maturity of unpaid
                  interest, it will not, except with the approval of Holders of
                  a majority in principal amount of Debentures then outstanding
                  expressed by written notice or resolution passed at a meeting
                  of Holders held in accordance with Article 12, directly or
                  indirectly extend or assent to the extension of the time for
                  payment of any interest payable hereunder or be a party to or
                  approve any such arrangement by funding any of such interest
                  or in any other manner. In case the time for payment of any
                  such interest shall be so extended, whether for a definite
                  period or otherwise, such interest shall not be entitled in
                  case of default hereunder to the benefit of this Indenture,
                  except subject to the prior payment in full of the principal
                  of all Debentures then outstanding and of all interest on such
                  Debentures, the payment of which has not been so extended;


<PAGE>   52
                                      -46-


         (g)      It will cause the Debentures and, subject to Section 5.5, the
                  Exchangeable Shares to remain listed and posted for trading
                  (or the functional equivalent thereof) on the TSE;

         (h)      It will, at the relevant times and upon exercise of the
                  relevant rights or elections, comply and take all measures
                  necessary to comply at all times with Section 3.6(3), Section
                  4.1(4) and Section 4.3(6);

         (i)      It will, forthwith upon being notified of any default or event
                  of default by the holders of Senior Liabilities, as
                  contemplated in Section 6.4(2), notify the Trustee of such
                  default or event of default; and

         (j)      Generally, it will duly and punctually perform and carry out
                  all of the acts or things to be done by it as provided in this
                  Indenture.

SECTION 8.2 TRUSTEE TO GIVE NOTICE OF EVENT OF DEFAULT.

         The Trustee shall give to the Holders of Debentures, the Corporation
and the Guarantor in the manner provided for in Section 2.16 or Section 2.18, as
the case may be, within 30 days after the Trustee becomes aware of the
occurrence of any Event of Default, notice of every such Event of Default
continuing at the time the notice is given, unless the Trustee reasonably and in
good faith determines that it is in the best interests of the Debentureholders
to withhold such notice and so informs the Corporation and the Guarantor in
writing.

SECTION 8.3 PERFORMANCE OF COVENANTS BY TRUSTEE.

         If the Corporation or the Guarantor fails to perform any of their
respective covenants contained in this Indenture, the Trustee may notify the
Holders of such failure or may itself perform any of such covenants capable of
being performed by it, but shall be under no obligation to do so. All sums so
expended or advanced by the Trustee shall be repayable as provided in Section
14.7. No such performance or advance by the Trustee shall relieve or be deemed
to relieve the Corporation or the Guarantor of any default hereunder.

SECTION 8.4 COVENANT OF THE GUARANTOR.

         The Guarantor will annually, within 120 days of the Guarantor's fiscal
year end (and at any other reasonable time upon demand by the Trustee), deliver
to the Trustee (i) an Officers' Certificate confirming that it has complied with
all requirements contained in this Indenture that, if not complied with, would,
with the giving of notice, lapse of time or otherwise, constitute an Event of
Default, or, if there has been failure to comply, giving particulars thereof and
(ii) audited consolidated financial statements of the Guarantor for the previous
fiscal year.


<PAGE>   53
                                      -47-


                                    ARTICLE 9
                             DEFAULT AND ENFORCEMENT

SECTION 9.1 EVENTS OF DEFAULT.

         If and when any one or more of the following events (herein called an
"EVENT OF DEFAULT") shall happen with respect to the Debentures, namely:

         (a)      A default in payment of principal of the Debentures when due
                  in cash or by delivery of Exchangeable Shares as required
                  hereunder;

         (b)      A default in payment of interest on the Debentures when due
                  and payable and the continuance of such default for 30 days;

         (c)      A default in performing or observing any of the other
                  covenants, agreements or obligations of the Corporation or the
                  Guarantor as provided herein and the continuance of such
                  default for 60 days after written notice to the Corporation or
                  the Guarantor, respectively, by the Trustee or by the Holders
                  of not less than 25% in principal amount of Debentures then
                  outstanding specifying such default and requiring the same to
                  be remedied, or such longer period of time as the Trustee
                  (having regard to the subject matter of such neglect or
                  non-observance) shall agree to;

         (d)      A decree, judgment, or order by a court having jurisdiction in
                  the premises shall have been entered adjudging the Corporation
                  or the Guarantor a bankrupt or insolvent or approving as
                  properly filed a petition seeking reorganization,
                  readjustment, arrangement, composition or similar relief for
                  the Corporation or the Guarantor, under the Bankruptcy and
                  Insolvency Act (Canada) or any other bankruptcy, insolvency or
                  analogous applicable law of Canada or any province thereof or
                  of England or appointing under any such law a liquidator or
                  trustee or assignee in bankruptcy or insolvency of the
                  Corporation or the Guarantor or of a substantial part of its
                  property, or ordering pursuant to any such law the winding up
                  or liquidation of the affairs of the Corporation or the
                  Guarantor, and such decree, judgement or order shall have
                  remained in force for a period of 30 consecutive days; or any
                  substantial part of the property of the Corporation or the
                  Guarantor shall be sequestered or attached and shall not be
                  returned to the possession of the Corporation or the Guarantor
                  or released from such attachment, as the case may be, whether
                  by filing of a bond, or stay or otherwise, within 30
                  consecutive days thereafter;

         (e)      The Corporation or the Guarantor shall institute proceedings
                  to be adjudicated a voluntary bankrupt, or shall consent to
                  the filing of a


<PAGE>   54
                                      -48-


                  bankruptcy proceeding against it, or shall file a petition or
                  answer or consent seeking reorganization, readjustment,
                  arrangement, composition or similar relief under the
                  Bankruptcy and Insolvency Act (Canada) or any other
                  bankruptcy, insolvency or analogous applicable law of Canada
                  or any province thereof or of England or shall consent to the
                  filing of any such petition, or shall consent to the
                  appointment of a receiver or liquidator or trustee or assignee
                  in bankruptcy or insolvency for it or of a substantial part of
                  its property, or shall make an assignment for the benefit of
                  creditors, or shall admit in writing its inability, to pay its
                  debts generally as they become due; or

         (f)      A default in respect of any indebtedness for borrowed money of
                  the Corporation or the Guarantor having an outstanding
                  principal amount of fifty million U.S. dollars
                  (U.S.$50,000,000) or more, whether such indebtedness now
                  exists or shall hereafter be created, which default has caused
                  the holder of such indebtedness to declare such indebtedness
                  to be due and payable prior to the date on which it would
                  otherwise become or be due and payable and such acceleration
                  is not rescinded or annulled within 10 days after the date of
                  such acceleration;

then, and in each and every such case which has occurred and is continuing, the
Trustee may, in its discretion, and shall, upon the written request of the
Holders of not less than 25% in principal amount of Debentures then outstanding,
declare the principal of, together with accrued interest on all such Debentures
and all other amounts payable hereunder to be due and payable immediately, by a
notice in writing to the Corporation and the Guarantor (and to the Trustee if
given by the Holders), and upon any such declaration such principal amount,
together with accrued interest thereon, and such other amounts shall become
immediately due and payable.

SECTION 9.2 WAIVER.

         At any time after such a declaration of acceleration with respect to
the Debentures has been made and before a judgment or decree for payment of the
money due has been obtained by the Trustee as hereinafter provided, the Holders
of a majority in principal amount of Debentures then outstanding, by written
notice to the Corporation and the Trustee, may thereupon rescind and annul such
declaration and its consequences if the Corporation or the Guarantor has paid or
deposited with the Trustee a sum sufficient to pay:

         (a)      All overdue interest on all Debentures;

         (b)      The principal of any of the Debentures which have become due
                  otherwise than by such declaration of acceleration, and
                  interest thereon from the date of such declaration at the rate
                  prescribed therefor in the Debentures


<PAGE>   55
                                      -49-


                  and all other moneys payable hereunder other then as a result
                  of such declaration of acceleration; and

         (c)      To the extent that payment of such interest is lawful and
                  applicable, interest upon overdue instalments of interest at
                  the rate prescribed therefor in such Debentures; and

all Events of Default with respect to the Debentures, other than the non-payment
of the principal of and interest on the Debentures which have become due solely
by such declaration of acceleration, have been cured or waived in accordance
with the provisions of this Indenture.

SECTION 9.3 WAIVER OF DEFAULT OR BREACH.

(1)      The Holders of not less than a majority in principal amount of the
         Debentures then outstanding may on behalf of the Holders of all
         Debentures waive any past default hereunder with respect to the
         Debentures and its consequences, except a default:

         (a)      In the payment of the principal of or interest on a Debenture;
                  or

         (b)      In respect of a covenant or provision hereof that under
                  Article 13 cannot be modified or amended without the consent
                  of the Holder of each Debenture then outstanding.

(2)      Upon any such waiver, such default shall cease to exist, and any Event
         of Default arising therefrom shall be deemed to have been cured, for
         every purpose of this Indenture. No such waiver shall extend to any
         subsequent or other default or impair any right consequent thereon.

SECTION 9.4 OTHER REMEDIES.

(1)      If an Event of Default occurs and is continuing, the Trustee, upon
         being funded and indemnified to its reasonable satisfaction, may pursue
         any available remedy to collect the payment of principal of or interest
         on the Debentures or to enforce the performance of any term of the
         Debentures or this Indenture.

(2)      The Trustee may maintain a proceeding even if it does not possess any
         Debentures or does not produce any of them in the proceeding. A delay
         or omission by the Trustee or any Holder in exercising any right or
         remedy accruing upon an Event of Default shall not impair the right or
         remedy or constitute a waiver of or acquiescence to the Event of
         Default.

SECTION 9.5 APPLICATION OF MONEY COLLECTED.

         Subject to Article 6, any money collected by the Trustee pursuant to
this Article 9 shall be applied in the following order, at the dates fixed by
the Trustee and, in case of


<PAGE>   56
                                      -50-


the distribution of such money on account of principal or interest, upon
presentation of Debentures and the notation thereon of the payment if only
partially paid and upon surrender thereof if fully paid:

         (a)      First, to the payment of all amounts due to the Trustee under
                  Section 14.7;

         (b)      Second, to the payment of all amounts then due and unpaid for
                  principal of and interest on the Debentures and other moneys
                  payable hereunder in respect of which or for the benefit of
                  which such money has been collected rateably, without
                  preference or priority of any kind, according to the amounts
                  due and payable on the Debentures for principal and interest,
                  respectively (less any tax required by law to be deducted);
                  and

         (c)      Lastly, the surplus (if any) of such moneys shall be paid to
                  the Corporation, the Guarantor or their respective assigns,
                  unless otherwise required by law;

provided, however, that no payment shall be made pursuant to Section 9.5(b) in
respect of the principal or interest of any Debenture held, directly or
indirectly, by or for the benefit of the Corporation or the Guarantor or any
subsidiary or Affiliate thereof (other than any Debenture pledged for value and
in good faith to a Person, other than the Corporation or the Guarantor or any of
their subsidiaries or Affiliates, but only to the extent of such Person's
interest therein), except subject to the prior payment in full of the principal
and interest of all Debentures which are not so held.

SECTION 9.6 CONTROL BY HOLDERS.

         Subject to Section 9.7, the Holders of at least a majority in principal
amount of the Debentures then outstanding, may:

         (a)      Direct the time, method and place (in Toronto, Ontario) of
                  conducting any proceeding for any remedy available to the
                  Trustee or exercising any trust or power conferred on it with
                  respect to the Debentures, provided that the Trustee has been
                  funded and indemnified to its reasonable satisfaction; and

         (b)      Take any other action authorized to be taken by or on behalf
                  of the Holders of any specified aggregate principal amount of
                  Debentures under any provisions of this Indenture or under
                  applicable law.

SECTION 9.7 LIMITATION ON SUITS.

(1)      A Holder of Debentures may pursue a remedy with respect to this
         Indenture directly itself only if: (i) the Holder gives to the Trustee
         notice of a continuing Event of Default; (ii) the Holders of at least
         25% in principal amount of the Debentures then outstanding make a
         request in writing to the Trustee to pursue


<PAGE>   57
                                      -51-


         the remedy; (iii) such Holder or Holders offer or provide to the
         Trustee funding and indemnity in form satisfactory to the Trustee
         against any loss, liability or expense; (iv) the Trustee does not
         comply with the request within 30 days after receipt of such request,
         funding and indemnity; and (v) during such 30-day period the Holders of
         a majority in principal amount of Debentures then outstanding do not
         give the Trustee a direction inconsistent with the request.

(2)      Holders may not use this Indenture to prejudice the rights of another
         Holder or to obtain a preference or priority over another Holder.

SECTION 9.8 RIGHTS OF HOLDERS TO RECEIVE PAYMENT.

         Notwithstanding any other provision of this Indenture, the right of any
Holder to receive payment of principal of and interest on Debentures held by it,
on or after the respective due dates expressed in the Debentures (or, in the
case of redemption, on the Redemption Date), or to bring suit for the
enforcement of any such payment on or after such respective dates, shall not be
impaired or affected without the consent of the Holder.

SECTION 9.9 COLLECTION SUIT BY TRUSTEE.

         If an Event of Default specified in Section 9.1(a), Section 9.1(b),
Section 9.1(c) or Section 9.1(f) occurs and is continuing, the Trustee may
recover judgment in its own name and as trustee of an express trust against the
Corporation and/or the Guarantor for the whole amount of principal and interest
remaining unpaid.

SECTION 9.10 TRUSTEE MAY FILE PROOFS OF CLAIM.

         The Trustee may file such proofs of claim and other papers or documents
as may be necessary or advisable in order to have the claims of the Trustee and
the Holders lodged or allowed in any judicial proceedings relative to the
Corporation, the Guarantor or their respective creditors or property.

SECTION 9.11 UNDERTAKING FOR COSTS.

         In any suit for the enforcement of any right or remedy under this
Indenture or in any suit against the Trustee for any action taken or omitted by
it as Trustee, a court in its discretion may require the filing by any party
litigant in the suit of an undertaking to pay the costs of the suit, and the
court in its discretion may assess reasonable costs, including reasonable
attorneys' fees, against any party litigant in the suit, having due regard to
the merits and good faith of the claims or defences made by the party litigant.
This Section 9.11 does not apply to a suit by the Trustee, a suit by a Holder
pursuant to Section 9.7, or a suit by any Holder or group of Holders of more
than 10% in principal amount of the Debentures then outstanding.


<PAGE>   58
                                      -52-


SECTION 9.12 DELAY OR OMISSION NOT WAIVER.

         No delay or omission of the Trustee or of any Holder of Debentures to
exercise any right or remedy accruing upon any Event of Default shall impair any
such right or remedy or constitute a waiver of any such Event of Default or an
acquiescence therein. Every right and remedy given by this Article 9 or by law
to the Trustee or to the Holders may be exercised from time to time, and as
often as may be deemed expedient, by the Trustee or by the Holders, as the case
may be.

SECTION 9.13 REMEDIES CUMULATIVE.

         No remedy herein conferred upon or reserved to the Trustee or upon or
to the Holders is intended to be exclusive of any other remedy, but each remedy
shall be cumulative and shall be in addition to every other remedy given
hereunder or now existing or hereafter to exist by law or statute.

SECTION 9.14 JUDGMENT AGAINST THE CORPORATION AND/OR THE GUARANTOR.

         The Corporation and the Guarantor covenants and agrees with the Trustee
that, in case of any judicial or other proceedings to obtain judgment for
payment of the principal of or interest on the Debentures, judgment may be
rendered against either of them in favour of the Holders or in favour of the
Trustee, as trustee for the Holders, for the amount which may remain due in
respect of the Debentures and the interest thereon.

SECTION 9.15 DISTRIBUTION OF PROCEEDS.

         Payments to Holders of Debentures pursuant to Section 9.5(b) shall be
made as follows:

         (a)      At least 10 days' notice of every such payment shall be given
                  in the manner provided in Section 2.16 specifying the time
                  when and the place or places where the Debentures are to be
                  presented and the amount of the payment and the application
                  thereof as between principal, interest and any other moneys
                  payable hereunder;

         (b)      Payment of any Debenture shall be made upon presentation
                  thereof at any one of the places specified in such notice and
                  any such Debenture thereby paid in full shall be surrendered,
                  otherwise a memorandum of such payment shall be endorsed
                  thereon; but the Trustee may in its discretion dispense with
                  presentation and surrender or endorsement in any special case
                  upon such indemnity being given as it shall deem sufficient;

         (c)      From and after the date of payment specified in the notice,
                  interest shall accrue only on the amount which remains unpaid
                  on each Debenture after giving effect to the payment specified
                  in such notice, unless such


<PAGE>   59
                                      -53-


                  Debenture be duly presented on or after the date so specified
                  and payment of such amount be not made; and

         (d)      The Trustee shall not be required to make any interim payment
                  to Debentureholders, unless the moneys in its hands, after
                  reserving therefrom such amount as the Trustee may think
                  necessary to provide for the payments mentioned in Section
                  9.5(a), exceed 5% of the principal amount of the Debentures.

SECTION 9.16 IMMUNITY OF SHAREHOLDERS, ETC.

         The Debentureholders and the Trustee hereby waive and release any
right, cause of action or remedy now or hereafter existing in any jurisdiction
against, any past, present or future incorporator, shareholder, director or
officer (as such) of the Corporation for the payment of the principal or
interest on any of the Debentures or on any covenant, agreement, representation
or warranty by the Corporation herein or in the Debentures contained; provided,
however, that nothing in this section shall prevent recourse to and the
enforcement of liability of any such incorporator, shareholder, director or
officer of the Corporation based upon the fraud of such incorporator,
shareholder, director or officer.

SECTION 9.17 TRUSTEE APPOINTED ATTORNEY.

         The Corporation hereby irrevocably appoints the Trustee to be the
attorney of the Corporation for and in the name and on behalf of the Corporation
to execute any instrument and do any acts and things which the Corporation ought
to sign, execute and do hereunder and generally to use the name of the
Corporation in the exercise of all or any of the powers hereby conferred on the
Trustee, with full powers of substitution and revocation.

                                   ARTICLE 10
                           SATISFACTION AND DISCHARGE

SECTION 10.1 CANCELLATION AND DESTRUCTION.

         All matured Debentures shall forthwith after payment thereof be
delivered to the Trustee or to a Person appointed by it or by the Corporation
with the approval of the Trustee and cancelled. All Debentures cancelled or
required to be cancelled under this or any other provision of this Indenture may
be destroyed by or under the direction of the Trustee by cremation or otherwise
(in the presence of a representative of the Corporation, if the Corporation
shall so require) and the Trustee shall prepare and retain a certificate of such
destruction and deliver a duplicate thereof to the Corporation.


<PAGE>   60
                                      -54-


SECTION 10.2 NON-PRESENTATION OF DEBENTURES.

         If the Holder of any Debenture fails to present its Debenture for
payment on the date on which the principal thereof or represented thereby
becomes payable at maturity or otherwise or fails to accept payment on account
thereof in cash or Exchangeable Shares issued and delivered pursuant to the
provisions hereof or give such receipt therefor, if any, as the Trustee may
require:

         (a)      The Corporation shall be entitled to pay or issue and deliver,
                  as the case may be, to the Trustee and direct it to set aside;
                  or

         (b)      In respect of moneys in the hands of the Trustee which may or
                  should be applied to the payment of the Debentures, the
                  Corporation shall be entitled to direct the Trustee to set
                  aside;

the principal and interest, or the Exchangeable Shares, as the case may be, in
trust to be paid or delivered, as the case may be, without interest to the
Holder of such Debenture, upon due presentation and/or surrender thereof in
accordance with the provisions of this Indenture; and thereupon the principal
and interest payable on or represented by each Debenture in respect whereof such
moneys or Exchangeable Shares have been set aside shall be deemed to have been
paid and the Holder thereof shall thereafter have no right in respect thereof,
except that of receiving payment of the moneys or the Exchangeable Shares so set
aside by the Trustee upon due presentation and/or surrender thereof, subject
always to the provisions of Section 10.3.

SECTION 10.3 REPAYMENT OF UNCLAIMED MONEYS OR EXCHANGEABLE SHARES TO
             CORPORATION.

         Any moneys or Exchangeable Shares in the hands of the Trustee and set
aside under Section 10.2 and not claimed by and paid or delivered as provided in
Section 10.2, to Holders of Debentures within five years after the date of such
setting aside shall be repaid or delivered to the Corporation by the Trustee on
demand, and thereupon the Trustee shall be released from all further liability
with respect to such moneys and Exchangeable Shares and thereafter the Holders
of the Debentures in respect of which such moneys and Exchangeable Shares were
so repaid or delivered to the Corporation shall have no rights in respect
thereof, except to obtain payment of the moneys or delivery of the Exchangeable
Shares (or, after redemption or purchase of the Exchangeable Shares pursuant to
their terms or to the terms of the Plan, AMVESCAP Ordinary Shares) due thereon
from the Corporation.

SECTION 10.4 RELEASE FROM COVENANTS.

         Upon Written Request and proof being given to the reasonable
satisfaction of the Trustee that the principal of all the Debentures and
interest thereon and other moneys payable hereunder have been paid or satisfied
or that all the Debentures then outstanding have matured and that the payment or
satisfaction of all principal thereof,


<PAGE>   61
                                      -55-


interest thereon and other moneys payable has been duly and effectually provided
for, and upon payment of all costs, charges and expenses properly incurred by
the Trustee hereunder and all interest thereon and the remuneration of the
Trustee, or upon provision satisfactory to the Trustee being made therefor, the
Trustee shall, at the request and at the expense of the Corporation, execute and
deliver to the Corporation and the Guarantor such deeds or other instruments as
shall be requisite to release the Corporation and the Guarantor from the terms
of this Indenture and the Debentures, except those relating to the
indemnification of the Trustee.

                                   ARTICLE 11
       MERGER, AMALGAMATION, CONSOLIDATION, CONVEYANCE, TRANSFER OR LEASE

SECTION 11.1 AMALGAMATION AND CONSOLIDATION OF CORPORATION AND CONVEYANCES
             PERMITTED SUBJECT TO CERTAIN CONDITIONS.

         Neither the Corporation nor the Guarantor will consummate any
transaction (whether by way of merger, amalgamation, consolidation,
reorganization or arrangement (except with one or more of its wholly-owned
subsidiaries)) or effect any conveyance, transfer, lease, sale or otherwise of
all or substantially all of its undertaking or assets, unless in any such case:

         (a)      It shall be the continuing corporation, or the successor
                  corporation (or the Person that leases or that acquires by
                  conveyance, sale or transfer all or substantially all of the
                  assets of the Corporation or the Guarantor, as the case may
                  be) (such corporation or Person being referred to as the
                  "SUCCESSOR CORPORATION") shall expressly, by supplemental
                  indenture executed and delivered to the Trustee by such
                  Successor Corporation, assume and become bound by the
                  obligations of the Corporation or the Guarantor, as
                  applicable, under this Indenture, including without limitation
                  the due and punctual payment of the principal of and interest
                  on all Debentures then outstanding, according to their tenor,
                  and other moneys payable hereunder and the due and punctual
                  performance and observance of all the covenants and conditions
                  of this Indenture to be performed by the Corporation or the
                  Guarantor, as applicable; and

         (b)      It or such Successor Corporation, as the case may be, shall
                  not immediately thereafter be in default under this Indenture
                  or the Debentures.

SECTION 11.2 OFFICERS' CERTIFICATE AND OPINION OF COUNSEL.

         The Trustee may receive an Officers' Certificate and an Opinion of
Counsel as conclusive evidence that any such merger, amalgamation,
reorganization, arrangement,


<PAGE>   62
                                      -56-


lease, transfer, sale or conveyance, and any such assumption, comply with the
provisions of this Article 11.

SECTION 11.3 VESTING OF POWERS IN SUCCESSOR.

         Whenever the conditions of Section 11.1 have been duly observed and
performed, the Successor Corporation shall succeed to and be substituted for the
Corporation or the Guarantor, as the case may be, and shall agree to be bound by
the terms of this Indenture as principal obligor in place of the Corporation or
as guarantor in place of the Guarantor, as applicable, with the same effect as
if the Successor Corporation had been named herein and the Successor Corporation
shall possess and from time to time may exercise each and every right and power
of the Corporation or the Guarantor, as the case may be, under this Indenture in
the name of the Corporation or the Guarantor, as applicable, or otherwise and
any act or proceeding by any provisions of this Indenture required to be done or
performed by any directors or officers of the Corporation or the Guarantor, as
the case may be, may be done and performed with like force and effect by the
like directors or officers of such Successor Corporation.

SECTION 11.4 EXECUTION OF SUPPLEMENTAL INDENTURE.

         Upon being satisfied that the conditions of Section 11.1 have been duly
observed and performed by delivery of an Officers' Certificate and an Opinion of
Counsel as provided in Section 11.2, the Trustee shall execute any supplemental
indenture required, as provided in Article 13.

                                   ARTICLE 12
                          MEETINGS OF DEBENTUREHOLDERS

SECTION 12.1 PURPOSES FOR WHICH MEETINGS MAY BE CALLED.

         A meeting of Debentureholders may be called at any time and from time
to time pursuant to this Article 12 to make, give or take any Act provided by
this Indenture to be made, given or taken by Holders of Debentures.

SECTION 12.2 CALL, NOTICE AND PLACE OF MEETINGS.

(1)      The Trustee may at any time and from time to time and shall, on receipt
         of a requisition in writing made by the Corporation or by the Holders
         of at least 10% in principal amount of the Debentures then outstanding,
         which requisition shall set forth in reasonable detail the action
         proposed to be taken at such meeting, and upon being funded and
         indemnified to its reasonable satisfaction by the Corporation or the
         Holders making such requisition, as the case may be, against the costs
         which may be incurred in connection with the calling and holding of
         such meeting, call a meeting of Debentureholders for any purpose
         specified in Section 12.1, to be held at such time and at such place in
         Toronto, Ontario, as the


<PAGE>   63
                                      -57-


         Trustee shall determine. Notice of every meeting of Debentureholders,
         setting forth the time and place of such meeting and in general terms
         the action proposed to be taken at such meeting, shall be given, in the
         manner provided in Section 2.16, not less than 21 nor more than 50 days
         prior to the date fixed for the meeting.

(2)      If, pursuant to Section 12.2(1), the Corporation or Debentureholders
         have requested the Trustee to call a meeting of Debentureholders, and
         the Trustee shall not have made the first publication, or mailing, as
         the case may be, of notice of such meeting within 21 days after receipt
         of such request and funding and indemnity or shall not thereafter
         proceed to cause the meeting to be held as provided herein, then the
         Corporation or such Debentureholders, as the case may be, may determine
         the time and the place in Toronto, Ontario for such meeting and may
         call such meeting for such purposes by giving notice thereof as
         provided in Section 12.2(1).

SECTION 12.3 PERSONS ENTITLED TO VOTE AT MEETINGS.

         To be entitled to vote at any meeting of Debentureholders, a Person
shall be: (i) a Holder of one or more Debentures then outstanding; or (ii) a
Person appointed by an instrument in writing as proxy for a Holder or Holders of
one or more Debentures then outstanding by such Holder or Holders. The only
Persons who shall be entitled to be present or to speak at any meeting of
Debentureholders shall be the Persons entitled to vote at such meeting and their
counsel, any representatives of the Trustee and its counsel and any
representatives of the Corporation or the Guarantor and their counsel.

SECTION 12.4 QUORUM; ACTION.

(1)      The Persons entitled to vote at least 25% in principal amount of the
         Debentures then outstanding shall constitute a quorum for a meeting of
         Debentureholders. In the absence of a quorum within 30 minutes of the
         time appointed for any such meeting, the meeting shall, if convened at
         the request of Debentureholders, be dissolved. In the absence of a
         quorum in any other case the meeting shall be adjourned to be
         reconvened at the same time and place on the fifth Business Day
         following date of the meeting. At the reconvened meeting, the
         Debentureholders present in person or by proxy shall form a quorum and
         may transact the business for which the meeting was originally convened
         notwithstanding that they may not represent 25% of the principal amount
         of the outstanding Debentures. No notice of the reconvening of any
         adjourned meeting shall be given.

(2)      Except as limited by the proviso to Section 13.2(1), any resolution
         presented to a meeting or adjourned meeting duly reconvened at which a
         quorum is present as aforesaid may be adopted only by the affirmative
         vote of the Holders of a majority in principal amount of Debentures
         represented at the meeting and voted on such resolution; provided,
         however, that, except as limited by the


<PAGE>   64
                                      -58-


         proviso to Section 13.2(1), any resolution with respect to any Act that
         this Indenture expressly provides may be made, given or taken by the
         Holders of a specified percentage in principal amount of Debentures
         then outstanding may be adopted at a meeting or an adjourned meeting
         duly reconvened and at which a quorum is present as aforesaid by the
         affirmative vote of the Holders of such specified percentage in
         principal amount of Debentures then outstanding.

(3)      Any resolution passed or decision taken at any meeting of Holders of
         Debentures duly held in accordance with this section will be binding on
         all Holders of Debentures, whether or not present or represented at the
         meeting.

SECTION 12.5 DETERMINATION OF VOTING RIGHTS; CHAIRMAN; CONDUCT AND ADJOURNMENT
             OF MEETINGS.

(1)      Notwithstanding any other provisions of this Indenture, the Trustee or
         the Corporation, with the approval of the Trustee, may make and from
         time to time may vary such reasonable regulations as it may deem
         advisable for any meeting of Debentureholders in regard to proof of the
         holding of Debentures and the appointment of proxies and in regard to
         the appointment of scrutineers, the submission and examination of
         proxies, certificates and other evidence of the right to vote, and such
         other matters concerning the conduct of the meeting as it shall deem
         appropriate.

(2)      The Trustee shall, by an instrument in writing, appoint a chairman and
         secretary of the meeting, unless the meeting shall have been called by
         the Corporation in which case the Corporation shall, by an instrument
         in writing, appoint a chairman and secretary.

(3)      At any meeting of Debentureholders, each Holder of a Debenture or proxy
         shall be entitled to one vote for each one thousand Dollars ($1,000)
         principal amount of Debentures held or represented by him; provided,
         however, that no vote shall be cast or counted at any meeting in
         respect of any Debentures challenged as not outstanding and ruled by
         the chairman of the meeting to be not outstanding. The chairman of the
         meeting shall have no right to vote, except as a Holder of a Debenture
         or proxy.

(4)      Any meeting of Debentureholders duly called pursuant to Section 12.2 at
         which a quorum is present may be adjourned from time to time by Persons
         entitled to vote a majority in principal amount of Debentures then
         outstanding represented at the meeting; and the meeting may be held as
         so adjourned without further notice.

SECTION 12.6 COUNTING VOTES AND RECORDING ACTION OF MEETINGS.

         The vote upon any resolution submitted to any meeting of
Debentureholders shall be by written ballots on which shall be inscribed the
signatures of the


<PAGE>   65
                                      -59-


Debentureholders or of their representatives by proxy and the principal amounts
and serial numbers of Debentures then outstanding held or represented by them.
The chairman of the meeting shall appoint two scrutineers of votes who shall
count all votes cast at the meeting for or against any resolution and who shall
make and file with the secretary of the meeting their verified written reports
in triplicate of all votes cast at the meeting. A record, at least in duplicate,
of the proceedings of each meeting of Debentureholders shall be prepared by the
secretary of the meeting and there shall be attached to such record the original
reports of the scrutineers of votes on any vote by ballot taken thereat and
affidavits by one or more Persons having knowledge of the facts setting forth a
copy of the notice of the meeting and showing that such notice was given as
provided in Section 12.2. Each copy shall be signed and verified by the
affidavits of the chairman and secretary of the meeting and one such copy shall
be delivered to the Corporation, and another to the Trustee to be preserved by
the Trustee, the latter to have attached thereto the ballots voted at the
meeting. Any record so signed and verified shall be conclusive evidence of the
matters therein stated.

                                   ARTICLE 13
                             SUPPLEMENTAL INDENTURES

SECTION 13.1 SUPPLEMENTAL INDENTURES WITHOUT CONSENT OF HOLDERS.

         Without the consent of any Holders, the Corporation, when authorized by
a Board Resolution, the Guarantor, when duly authorized, and the Trustee, at any
time and from time to time, may enter into one or more indentures supplemental
hereto, in form satisfactory to the Trustee, in its sole discretion, for any of
the following purposes:

         (a)      To evidence the succession of another corporation to the
                  Corporation or the Guarantor, and the assumption by such
                  successor of the covenants and obligations herein of the
                  Corporation or of the Guarantor, respectively, and in the
                  Debentures;

         (b)      Adding to the provisions hereof such additional covenants,
                  enforcement provisions, release provisions and other
                  provisions as, in the Opinion of Counsel, are necessary or
                  advisable in the premises, provided that the same, in the
                  Opinion of Counsel, are not prejudicial to the interests of
                  the Debentureholders;

         (c)      To add any additional Events of Default;

         (d)      To evidence and provide for the acceptance of appointment
                  hereunder by a successor trustee with respect to the
                  Debentures;

         (e)      To cure any ambiguity, to correct or supplement any provision
                  herein that may be defective or inconsistent with any other
                  provision herein, or to


<PAGE>   66
                                      -60-


                  make any other provisions with respect to matters or questions
                  arising under this Indenture that shall not be inconsistent
                  with any provisions of this Indenture, provided such other
                  provisions shall not, in the Opinion of Counsel to the
                  Trustee, adversely affect the interests of the Holders of
                  Debentures in any material respect;

         (f)      Making any modification of any of the provisions of this
                  Indenture or the Debentures which is of a formal, minor or
                  technical nature;

         (g)      Making any additions to, deletions from or alterations of the
                  provisions of this Indenture (including any of the terms and
                  conditions of the Debentures) which, in the Opinion of Counsel
                  to the Trustee, are not prejudicial to the interests of the
                  Debentureholders and which are necessary or advisable in order
                  to incorporate, reflect or comply with any legislation the
                  provisions of which apply to this Indenture;

         (h)      Adding to or altering the provisions hereof in respect of the
                  transfer or exchange of the Debentures and making any
                  modification in the form of the Debentures which does not
                  affect the substance thereof and which, in the opinion of the
                  Trustee, is not prejudicial to the interests of the
                  Debentureholders;

         (i)      Correcting or rectifying any ambiguities, defective
                  provisions, errors or omissions herein, provided that, in the
                  Opinion of Counsel to the Trustee, the rights of the Trustee
                  and the Debentureholders are in no way prejudiced thereby; and

         (j)      Any other purpose not inconsistent with the terms of this
                  Indenture provided that, in the Opinion of Counsel to the
                  Trustee, the rights of the Trustee and of the Debentureholders
                  are in no way prejudiced thereby.

SECTION 13.2 SUPPLEMENTAL INDENTURES WITH CONSENT OF HOLDERS.

(1)      With the consent of the Holders of not less than a majority in
         aggregate principal amount of the Debentures represented at any meeting
         of Debentureholders duly called and held in accordance with the
         provisions of Article 12, or by Act of the Holders of not less than a
         majority in aggregate principal amount of the Debentures then
         outstanding delivered to the Corporation and the Trustee, the
         Corporation, when authorized by a Board Resolution, the Guarantor when
         duly authorized and the Trustee may enter into an indenture or
         indentures supplemental hereto for the purpose of adding any provisions
         to or changing in any manner or eliminating any of the provisions of
         this Indenture or of modifying in any manner the rights of the Holders
         under this Indenture; provided, however, that no such supplemental
         indenture shall, without the consent of the Holder of each Debenture
         then outstanding and so affected:


<PAGE>   67
                                      -61-


         (a)      Change the Maturity Date of the principal of, or any
                  instalment of interest on, the Debentures, or reduce the
                  principal amount thereof or the interest thereon or change any
                  place of payment, or change the currency in which the
                  Debentures or interest thereon is payable or modify or alter
                  the rights of the Holders to convert the Debentures into
                  Exchangeable Shares, or impair the right to institute a suit
                  for the enforcement of any such payment on or after the
                  Maturity Date thereof (or, in the case of redemption, on or
                  after the Redemption Date);

         (b)      Reduce the percentage in principal amount of the Debentures
                  then outstanding, the consent of whose Holders is required for
                  any such supplemental indenture, or the consent of whose
                  Holders is required for any waiver of compliance with certain
                  provisions of this Indenture or certain defaults hereunder and
                  their consequences provided for in this Indenture, or reduce
                  the requirements of Section 12.4 for quorum or Section 12.5
                  for voting; or

         (c)      Modify any provision of Section 8.1(d) or Section 8.4
                  regarding the annual delivery of an Officers' Certificate, or
                  modify any provisions of this Section or Section 9.3 except to
                  increase any percentage referred to in this Section or Section
                  9.3 or to provide that certain other provisions of this
                  Indenture cannot be modified or waived without the consent of
                  the Holder of each Debenture then outstanding.

(2)      It shall not be necessary for any Act of Holders under this Section to
         approve the particular form of any proposed supplemental indenture, but
         it shall be sufficient if such Act shall approve the substance thereof.

SECTION 13.3 EXECUTION OF SUPPLEMENTAL INDENTURES.

         In executing, or accepting the additional trusts created by, any
supplemental indenture permitted by this Article 13 or the modifications thereby
of the trusts created by this Indenture, the Trustee shall be entitled to
receive, and subject to Section 14.1, shall be fully protected in relying upon,
an Opinion of Counsel stating that the execution of such supplemental indenture
is authorized or permitted by this Indenture, is not inconsistent herewith, is a
valid and binding obligation of the Corporation, enforceable in accordance with
its terms, subject to enforceability being limited by bankruptcy, insolvency or
other laws affecting the enforcement of creditor's rights generally and
equitable remedies including the remedies of specific performance and injunction
being granted only in the discretion of a court of competent jurisdiction and
other qualifications that are customary in the circumstances and, in connection
with a supplemental indenture executed pursuant to Section 13.1, that the
Trustee is authorized to execute and deliver such supplemental indenture without
the consent of the Holders and, in connection with a supplemental indenture
executed pursuant to


<PAGE>   68
                                      -62-


Section 13.2, that the requisite consent of the Holders has been validly
obtained in accordance with Section 13.2. The Trustee may, but shall not be
obligated to, enter into any such supplemental indenture that affects the
Trustee's own rights, duties or immunities under this Indenture or otherwise.

SECTION 13.4 EFFECT OF SUPPLEMENTAL INDENTURES.

         Upon the execution of any supplemental indenture under this Article 13,
this Indenture shall be modified in accordance therewith, and such supplemental
indenture shall form a part of this Indenture for all purposes; and every Holder
of Debentures theretofore authenticated and delivered under this Indenture shall
be bound by such supplemental indenture.

                                   ARTICLE 14
                             CONCERNING THE TRUSTEE

SECTION 14.1 DUTIES OF TRUSTEE.

(1)      The Trustee in exercising its powers and discharging its duties
         hereunder shall:

         (a)      Act honestly and in good faith with a view to the best
                  interests of the Debentureholders; and

         (b)      Exercise the care, diligence and skill of a reasonably prudent
                  trustee.

(2)      The Trustee need perform only those duties that are specifically set
         forth in this Indenture and no others.

(3)      In the absence of bad faith on its part, the Trustee may conclusively
         act and rely, as to the truth of the statement and the correctness of
         the opinions expressed therein, upon statutory declarations,
         certificates, opinions or reports furnished to the Trustee and
         complying with the requirements of this Indenture.

(4)      Every provision of this Indenture that in any way relates to the
         Trustee is subject to the above paragraphs of this section. The Trustee
         may refuse to perform any duty or exercise any right or power unless it
         receives funding and indemnity reasonably satisfactory to it for
         actions taken under this Indenture. The Trustee shall not be liable for
         interest on any money received by it except as the Trustee may agree
         with the Corporation.

(5)      The Trustee shall not be liable for any error of judgment made in good
         faith by a responsible officer, unless it shall be proved that the
         Trustee was negligent in ascertaining the pertinent facts.


<PAGE>   69
                                      -63-


(6)      No provision of this Indenture shall require the Trustee to expend or
         risk its own funds or otherwise incur any personal financial liability
         in the performance of any of its duties hereunder, or in the exercise
         of any of its rights or powers.

SECTION 14.2 RIGHTS OF TRUSTEE.

(1)      The Trustee may act and rely on any document believed by it to be
         genuine and to have been signed or presented by the proper Person. The
         Trustee need not investigate any fact or matter stated in the document.
         Before the Trustee acts or refrains from acting, it may require an
         Officers' Certificate or an Opinion of Counsel. The Trustee shall not
         be liable for any action it takes or omits to take in good faith in
         reliance thereon. The Trustee may act through agents and shall not be
         responsible for the misconduct or negligence of any agent appointed
         with due care. The Trustee shall not be liable for any action it takes
         or omits to take in good faith, except as otherwise provided in this
         Indenture, which it reasonably believes to be authorized or within its
         rights or powers.

(2)      Any order, request or direction of the Corporation mentioned herein
         shall be sufficiently evidenced by a written request or order signed in
         the name of the Corporation by any authorized officer and any
         resolution of the Board of Directors shall be sufficiently evidenced by
         a Board Resolution.

(3)      Whenever in the administration of this Indenture the Trustee shall deem
         it desirable that a matter be proved or established prior to taking,
         suffering or omitting any action hereunder, the Trustee (unless other
         evidence be herein specifically prescribed) may, in the absence of bad
         faith on its part, rely upon an Officers' Certificate, including (i) as
         to any statements of fact, as evidence of the truth of such statements,
         and (ii) to the effect that any particular dealing or transaction or
         step or thing is, in the opinion of the officers so certifying,
         expedient, as evidence that it is expedient; provided that the Trustee
         may in its sole discretion require from the Corporation or otherwise
         further evidence or information before acting or relying on such
         certificate.

(4)      The Trustee may employ or retain such agents, Counsel, accountants and
         other assistants (at the Corporation's expense) as it may reasonably
         require for the proper determination and discharge of duties hereunder
         and may pay reasonable remuneration for all services performed for it.

(5)      The Trustee may, in relation to this Indenture, act and rely on the
         opinion or advice of or on information obtained from any Counsel,
         notary, valuer, surveyor, engineer, broker, auctioneer, accountant or
         other expert, whether retained, employed or appointed by the Trustee or
         by the Corporation or otherwise and shall not be responsible for any
         loss occasioned by such act or reliance unless such act or reliance was
         taken in bad faith or constituted gross negligence or


<PAGE>   70
                                      -64-


         wilful misconduct. The fees of such Counsel or other experts shall be
         added to and be part of the Trustee's fees hereunder.

(6)      The Trustee may consult with Counsel and written advice of such Counsel
         or any Opinion of Counsel shall be full and complete authorization and
         protection in respect of any action taken, suffered or omitted by it
         hereunder in good faith and in reliance thereon.

(7)      The Trustee shall be under no obligation to exercise any of the rights
         or powers vested in it by this Indenture at the request or direction of
         any of the Holders pursuant to this Indenture, unless such Holders
         shall have offered and furnished to the Trustee funds for the purpose
         and reasonable indemnity against the costs, expenses and liabilities
         which might be incurred by it in compliance with such request or
         direction.

(8)      Prior to the occurrence of an Event of Default with respect to the
         Debentures and after the occurrence of, during the continuance of or
         after the waiving of all such Events of Default which may have
         occurred, the Trustee shall not be bound to make any investigation into
         the facts or matters stated in any resolution, certificate, statement,
         instrument, opinion, report, notice, request, direction, consent,
         order, bond, debenture, note, coupon, other evidence of indebtedness or
         other paper or document, or any investigation of the books and records
         of the Corporation (but the Trustee, in its discretion, may make such
         further inquiry or investigation and shall be entitled to examine the
         books, records and premises of the Corporation, personally or by agent
         or attorney), unless requested to do so by the Act of the Holders of a
         majority in aggregate principal amount of the Debentures then
         outstanding; provided, however, that the Trustee may require reasonable
         funding and indemnity against the cost, expenses or liabilities likely
         to be incurred by it in the making of such investigation.

(9)      The Trustee may execute any of the trusts or powers hereunder or
         perform any duties hereunder either directly or by or through agents or
         attorneys, and the Trustee shall not be responsible for any misconduct
         or negligence on the part of any agent or attorney appointed with due
         care by it hereunder.

(10)     Nothing herein contained shall impose any obligation on the Trustee to
         see or to require evidence of registration or filing (or renewals
         thereof) of this Indenture or any instrument ancillary or supplemental
         hereto.

(11)     The Trustee shall not be bound to give any notice of the execution
         hereof.

(12)     The Trustee shall not incur any liability or responsibility whatever or
         be in any way responsible for the consequence of any breach on the part
         of the Corporation


<PAGE>   71
                                      -65-


         or the Guarantor of any of the covenants herein contained or of any act
         of the agents or servants of the Corporation or the Guarantor.

(13)     The Trustee shall not be liable for the price at which Exchangeable
         Shares are sold pursuant to the provisions of this Indenture, the
         timing of such sales or the failure to effect such sales, provided that
         it acts in accordance with Section 14.1 and follows the directions of
         the Corporation in undertaking such sales.

(14)     The Trustee (i) shall be entitled to act and rely on any Officers'
         Certificate it receives pursuant to Section 5.6(4); (ii) shall not at
         any time be under any duty or responsibility to any Debentureholder to
         determine whether any facts exist which may require any adjustment to
         the AMVESCAP Share Rate or revision to the Current Market Price, or
         with respect to the nature or extent of any such adjustment or revision
         when made, or with respect to the method employed in making such
         adjustment or revision; (iii) shall not be accountable with respect to
         the validity or value (or the kind or amount) of any Exchangeable
         Shares or of any other shares or securities or property which may at
         any time be issued or delivered upon the conversion of any Debenture or
         the exercise of the Share Redemption Right or the Share Repayment
         Right; and (iv) shall not be responsible for any failure of the
         Corporation to make any cash payment or to issue, transfer or deliver
         Exchangeable Shares upon the conversion of any Debenture or the
         exercise of the Share Redemption Right or the Share Repayment Right.

SECTION 14.3 DOCUMENTS, MONEYS, ETC., HELD BY TRUSTEE.

         Any securities, documents of title or other instruments that may at any
time be held by the Trustee subject to the trusts hereof may be placed in the
deposit vaults in the Province of Ontario of the Trustee or of any Canadian
chartered bank (a "QUALIFIED INSTITUTION"), including, without limitation, the
Canadian Imperial Bank of Commerce, or deposited for safekeeping in the Province
of Ontario with any such bank. Unless herein otherwise expressly provided, any
moneys so held, pending the application or withdrawal thereof under any
provision of this Indenture, may be deposited in the name of the Trustee in any
Canadian chartered bank at the rate of interest (if any) then current on similar
deposits or, (i) with the consent of the Corporation, may be deposited in the
deposit department of the Trustee or any other loan or trust corporation
authorized to accept deposits under the laws of Canada or a province thereof, or
(ii) at the written direction of the Corporation, the Trustee shall invest or
reinvest such monies in short term interest bearing or discount debt obligations
issued or guaranteed by the Government of Canada or any province thereof or a
Canadian chartered bank (which may include an Affiliate or related party of the
Trustee), maturing not more than one year from the date of investment, provided
that each such obligation is rated at least R1 (middle) by DBRS Inc. or any
equivalent rating by Canadian Bond Rating Service (an "AUTHORIZED INVESTMENTS").
Any direction by the Corporation to the Trustee as to


<PAGE>   72
                                      -66-


investment or reinvestment of funds shall be in writing and shall be provided to
the Trustee no later than 9:00 a.m. (local time) on the day on which the
investment is to be made. Any such direction received after 9:00 a.m. (local
time) or received on a non-Business Day, shall be deemed to have been given
prior to 9:00 a.m. (local time) the immediately following Business Day. If no
such direction is received, the Trustee shall not have any obligation to invest
the monies in Authorized Investments and pending receipt of such a direction
shall be entitled to hold such monies uninvested in a trust account. The Trustee
shall not be held liable for any losses incurred in the investment of any funds
in Authorized Investments. All interest or other income received by the Trustee
in respect of such deposits and investments shall belong to the Corporation and
shall be remitted to the Corporation upon request five years from Maturity Date,
unless an Event of Default shall have occurred and be continuing, in which case
all such interest and income shall be held by the Trustee and applied in
accordance with Section 9.5.

SECTION 14.4 INDIVIDUAL RIGHTS OF TRUSTEE.

         The Trustee in its individual or any other capacity may become the
owner or pledgee of Debentures and may otherwise deal with the Corporation and
the Guarantor with the same rights it would have if it were not Trustee. Any
agent of the Trustee may do the same with like rights. However, the Trustee is
at all time subject to Section 14.1 and Section 14.10.

SECTION 14.5 TRUSTEE'S DISCLAIMER.

         The Trustee makes no representation as to the validity or adequacy of
the Debentures, it shall not be accountable for the Corporation's use of the
proceeds from Debentures, and it shall not be responsible for any statement with
respect to the Debentures other than its certificate of authentication.

SECTION 14.6 DISCRETION OF TRUSTEE.

         Subject to Section 14.1, unless and until it shall have been required
to do so under the terms hereof, the Trustee shall not be bound to do or take
any act, action or proceeding in virtue of the powers conferred on it hereby;
nor shall the Trustee be required to take notice of any Event of Default
hereunder, other than in payment of any moneys required by any provision hereof
to be paid to it or where it has actual knowledge thereof, unless and until
notified in writing of such Event of Default (which notice shall distinctly
specify the Event of Default desired to be brought to the attention of the
Trustee) and in the absence of any such notice and subject as aforesaid, the
Trustee may for all purposes of this Indenture conclusively assume that the
Corporation is not in default hereunder and that no Event of Default has been
made with respect to the payment of principal and interest on the Debentures, or
in the observances or performance of any of the covenants, agreements or
conditions contained herein. Subject to Section 14.1, and except as otherwise
herein stated, any such notice or requisition shall in no way limit any
discretion herein given to the Trustee to determine


<PAGE>   73
                                      -67-


whether or not the Trustee shall take action with respect to any Event of
Default or take action without any such notice or requisition. The Trustee may,
before commencing or at any time during the continuance of any such action,
require the Holders at whose instance it is acting to deposit with the Trustee
the Debentures held by them, for which Debentures the Trustee shall issue
receipts.

SECTION 14.7 COMPENSATION AND INDEMNITY.

(1)      The Corporation shall pay to the Trustee from time to time compensation
         for its services hereunder as agreed separately by the Corporation and
         the Trustee, and shall pay or reimburse the Trustee upon its request
         for all reasonable expenses, disbursements and advances incurred or
         made by the Trustee in the administration or execution of its duties
         under this Indenture (including the reasonable and documented
         compensation and disbursements of its Counsel and all other advisers
         and assistants not regularly in its employ), both before any default
         hereunder and thereafter until all duties of the Trustee under this
         Indenture shall be finally and fully performed. The Trustee's
         compensation shall not be limited by any law on compensation of a
         trustee of an express trust.

(2)      The Corporation hereby indemnifies and saves harmless the Trustee and
         its directors, officers, employees and agents against any loss,
         damages, charges, expenses, claims, actions or liability whatsoever
         which the Trustee suffers or incurs as a result of or arising out of
         its duties and obligations hereunder. The foregoing provisions of this
         Section do not apply to the extent that in any circumstances there has
         been a failure by the Trustee or its employees to act honestly and in
         good faith or to discharge the Trustee's obligations under Section
         14.1(1). This indemnity will survive the termination or discharge of
         this Indenture and the resignation or removal of the Trustee. The
         Trustee shall notify the Corporation promptly of any claim for which it
         may seek indemnity. The Corporation shall defend the claim and the
         Trustee shall co-operate in the defence. The Trustee may have separate
         Counsel and the Corporation shall pay the reasonable fees and expenses
         of such Counsel. The Corporation need not pay for any settlement made
         without its consent, which consent must not be unreasonably withheld.

(3)      Any amount due under this Section 14.7 and unpaid 30 days after demand
         for such payment shall bear interest from the expiration of such 30
         days, at the rate normally charged by the Trustee on overdue accounts.
         Such amount shall continue to be payable after the occurrence of an
         Event of Default and until the trusts hereof shall be finally wound up
         and whether or not the trusts of this Indenture shall be in the course
         of administration by or under the direction of the court.


<PAGE>   74
                                      -68-


SECTION 14.8 REPLACEMENT OF TRUSTEE.

(1)      A resignation or removal of the Trustee and appointment of a successor
         trustee shall become effective only upon the successor trustee's
         acceptance of appointments as provided in this section.

(2)      The Trustee may resign at any time with respect to the Debentures by
         giving written notice thereof to the Corporation who shall appoint a
         successor trustee within 30 days. If an instrument of acceptance by a
         successor shall not have been delivered to the Trustee within 30 days
         after the giving of such notice of resignation, the resigning Trustee,
         at the Corporation's expense, may petition any court of competent
         jurisdiction for the appointment of a successor trustee. The Holders of
         not less than a majority in principal amount of the Debentures then
         outstanding may remove the Trustee by so notifying the Trustee and the
         Corporation. If: (i) the Trustee fails to comply with Section 14.1 or
         Section 14.10; (ii) the Trustee is adjudged to be bankrupt or
         insolvent; (iii) a receiver or public officer takes charge of the
         Trustee or its property; or (iv) the Trustee becomes incapable of
         acting, then, in any such case, the Corporation by a Board Resolution
         may remove the Trustee.

(3)      If the Trustee resigns or is removed or if a vacancy exists in the
         office of Trustee for any reason with respect to the Debentures, the
         Corporation shall promptly appoint a successor trustee with respect to
         the Debentures and shall comply with the applicable requirements of
         this Section 14.8. Within one year after the successor trustee takes
         office, the Holders of a majority in principal amount of Debentures
         then outstanding may appoint a successor trustee to replace the
         successor trustee appointed by the Corporation. If a successor trustee
         does not take office within 60 days after the retiring Trustee resigns
         or is removed, the retiring Trustee, the Corporation or the Holders of
         not less than 10% in principal amount of the Debentures then
         outstanding may petition any court of competent jurisdiction for the
         appointment of a successor trustee with respect to the Debentures.

(4)      The Corporation shall give notice to the Debentureholders of each
         resignation and each removal of the Trustee with respect to the
         Debentures and each appointment of a successor trustee with respect to
         the Debentures in the manner provided in Section 2.16. Each notice
         shall include the name of the successor trustee with respect to the
         Debentures and its address.

(5)      In the case of an appointment hereunder of a successor trustee with
         respect to the Debentures, every such successor trustee so appointed
         shall execute, acknowledge and deliver to the Corporation and to the
         retiring Trustee an instrument accepting such appointment, and
         thereupon the resignation or removal of the retiring Trustee shall
         become effective and such successor trustee,


<PAGE>   75
                                      -69-


         without any further act, deed or conveyance, shall become vested with
         all the rights, powers, trusts and duties of the retiring Trustee; but
         on request of the Corporation or the successor trustee, such retiring
         Trustee shall, upon payment of its charges and any other amount owing
         to it hereunder, execute and deliver an instrument transferring to such
         successor trustee all the rights, powers and trusts of the retiring
         Trustee, and shall duly assign, transfer and deliver to such successor
         trustee all property and money held by such retiring Trustee hereunder.

(6)      Upon request of any such successor trustee, the Corporation shall
         execute any and all instruments for more fully and certainly vesting in
         and confirming to such successor trustee all such rights, powers and
         trusts referred to in Section 14.8(5).

(7)      No successor trustee shall accept its appointment unless at the time of
         such acceptance such successor trustee shall be qualified and eligible
         under this Article 14.

SECTION 14.9 SUCCESSOR TRUSTEE BY MERGER, ETC.

         If the Trustee consolidates, merges or converts into, or transfers all
or substantially all of its corporate trust business to, another corporation,
the successor corporation without any further act shall be the successor
trustee.

SECTION 14.10 ELIGIBILITY; DISQUALIFICATION.

         This Indenture shall always have a Trustee who satisfies the
requirements of Part V of the Business Corporations Act (Ontario). The Trustee
represents to the Corporation that at the date of the execution and delivery of
this Indenture no material conflict of interest exists in the Trustee's role as
a fiduciary hereunder and agrees that in the event of a material conflict of
interest arising hereafter the Trustee shall, within 90 days after ascertaining
that such a material conflict of interest exists, either eliminate such material
conflict of interest or resign its trust hereunder. If any such material
conflict of interest exists or hereafter shall exist, the validity and
enforceability of this Indenture and the Debentures shall not be affected in any
manner whatsoever by reason thereof.

SECTION 14.11 ACCEPTANCE OF TRUST.

         The Trustee hereby accepts the trusts in this Indenture declared,
created or constituted and provided for and agrees to perform the same upon the
terms and conditions herein set forth.

SECTION 14.12 ADDITIONAL EVIDENCE.

         In addition to the reports, certificates, opinions and other evidence
required by this Indenture, the Corporation shall furnish to the Trustee such
additional evidence of compliance with any provision hereof in such form as may
be prescribed by applicable


<PAGE>   76
                                      -70-


legislation or as the Trustee may reasonably require by written notice to the
Corporation.

SECTION 14.13 DEPOSIT OF DEBENTURES.

         The Trustee may, before commencing or at any time during the
continuance of any act, action or proceeding taken pursuant to this Indenture,
require the Debentureholders, at whose instance it is acting, to deposit with
the Trustee the Debentures held by them, for which Debentures the Trustee shall
issue receipts.

         IN WITNESS WHEREOF the parties have executed this Indenture.

                                       CIBC MELLON TRUST COMPANY

                                       By: /s/ MAXINE MCDONALD
                                          --------------------------------------
                                          Name: Maxine McDonald
                                          Title: Senior Manager, Client
                                                 Relations


                                       By: /s/ JEFFERY CARRABS
                                          --------------------------------------
                                          Name: Jeffery Carrabs
                                          Title: Manager, Client Relations

                                       AMVESCAP INC.

                                       By: /s/ ROBERT HAIN
                                          --------------------------------------
                                          Authorized Signing Officer


                                       AMVESCAP PLC

                                       By: /s/ ROBERT F. MCCULLOUGH
                                          --------------------------------------
                                          Authorized Signing Officer


<PAGE>   77


                                  SCHEDULE "A"

                                FORM OF DEBENTURE

                                                               CUSIP 03235K AA 4

NO. o                             AMVESCAP INC.                               $o
               INCORPORATED UNDER THE COMPANIES ACT (NOVA SCOTIA)

                     AMVESCAP EQUITY SUBORDINATED DEBENTURES

         AMVESCAP Inc. (the "CORPORATION"), for value received, hereby
acknowledges itself indebted and promises to pay to the order of the registered
holder hereof as set out on the reverse hereof, on the third anniversary of the
date hereof (the "MATURITY DATE"), or on such earlier date as the principal
amount hereof may become due in accordance with the provisions of the Indenture
hereinafter mentioned, the principal sum of

                                                                   o DOLLARS($o)

in lawful money of Canada, on presentation and surrender of this Debenture at
the principal office of CIBC Mellon Trust Company in the City of Toronto, and to
pay interest on the principal amount hereof at the rate of 6.00% per annum from
the date hereof or from the most recent Interest Payment Date to which interest
has been paid or made available for payment on the Debentures then outstanding,
whichever is later, in like money in equal semi-annual instalments in arrears,
commencing six months after the date hereof with overdue interest, if any, at
the same rate after as well as before maturity and after as well as before
default in payment of principal or interest.

         As interest on this Debenture becomes due, the Corporation (except in
case of payment of interest at maturity or on redemption or conversion, at which
time payment of interest, less any tax required by law to be deducted or
withheld, will be made upon surrender of this Debenture) shall forward or cause
to be forwarded by courier or ordinary post to the registered address of the
registered holder of the Debenture for the time being, or in the case of joint
holders to the registered address of one of such joint holders, a cheque for
such interest, less any tax required by law to be deducted or withheld, if any,
payable to the order of such holder or holders and negotiable at par. The
forwarding of such cheque shall satisfy and discharge the liability for interest
on this Debenture to the extent of the sum represented thereby (plus the amount
of any tax deducted or withheld as aforesaid), unless such cheque be not paid on
presentation.

         This Debenture is one of the AMVESCAP Equity Subordinated Debentures
(the "DEBENTURES") issued under an Indenture (the "INDENTURE") dated the date
hereof and made among the Corporation, CIBC Mellon Trust Company, as trustee
(the "TRUSTEE") and AMVESCAP PLC, as guarantor ("GUARANTOR"). Reference is
hereby made to the Indenture for a description of the rights of the Holders of
the Debentures, the Corporation, the Guarantor and the Trustee and of the terms
and conditions upon which the Debentures are


<PAGE>   78
                                      -2-


issued and held, all to the same effect as if the provisions of the Indenture
were herein set forth, to all of which provisions the Holder of this Debenture,
by acceptance hereof, assents. To the extent that the terms and conditions
stated in this Debenture conflict with the terms and conditions of the
Indenture, the latter prevails. All capitalized terms used herein have the
meanings ascribed thereto in the Indenture unless otherwise indicated.

         The Debentures are issuable as fully registered Debentures in
denominations of $1,000 and integral multiples of $1,000. The Debentures of any
authorized denomination may be exchanged, as provided in the Indenture, for
Debentures of the same aggregate principal amount in any other authorized
denomination.

         This Debenture and all other Debentures certified and issued under the
Indenture rank pari passu with one another, in accordance to their tenor without
discrimination, preference or priority. The payment of all amounts owing under
the Indenture including, without limitation, the principal of and interest on
the Debentures is subordinated to the prior payment in full of Senior
Liabilities as provided in Article 6 of the Indenture. The Indenture does not
restrict the Corporation from incurring additional Indebtedness for borrowed
money or from mortgaging, pledging or charging its properties to secure any
Indebtedness.

         At any time before the Maturity Date the Corporation may, upon at least
20 days' and not more than 30 days' notice, conditionally or unconditionally
redeem all, but not less than all, of the Debentures outstanding on a date
chosen by the Corporation for redemption (the "REDEMPTION DATE") upon payment in
lawful money of Canada of an amount, for each $1,000 principal amount of
Debentures to be redeemed, equal to the aggregate of (i) $1,200; plus (ii) all
accrued and unpaid interest on each such $1,000 principal amount to but
excluding the Redemption Date (collectively, the "REDEMPTION AMOUNT"). The
Corporation may satisfy the Redemption Amount in cash or by the delivery of that
number of Freely Tradeable Exchangeable Shares obtained by dividing the
Redemption Amount by 95% of the Current Market Price of an AMVESCAP Ordinary
Share on the date of the Redemption Notice. The Corporation may only exercise
its right to conditionally redeem all of the outstanding Debentures if there is
an Offer (that is a take-over bid or issuer bid to purchase AMVESCAP Ordinary
Shares or any other transaction which has a similar effect) and if the only
condition to the Corporation's exercise of its right to redeem all of the
outstanding Debentures is the completion of such Offer.

         Each Debentureholder has the right at its option, at any time and from
time to time, to convert its Debentures into Exchangeable Shares. In order to
exercise this right to convert, a Debentureholder is required to deliver to the
Trustee a conversion notice (the "CONVERSION NOTICE") in the form attached to
this Debenture, together with this Debenture, and to specify in such notice the
date on which such Debentureholder wants such conversion to be effective, which
date shall be not less than four Business Days and not more than 15 Business
Days from the day the Trustee receives such Conversion Notice. Each $1,000
principal amount of Debentures is convertible into that number of Exchangeable
Shares equal to the Conversion Number in effect on the date the Trustee


<PAGE>   79
                                      -3-


receives the applicable Conversion Notice. The Conversion Number will be
calculated as (i) the Conversion Value (being the lesser of the AMVESCAP Share
Value and $1,200) divided by (ii) the Current Market Price of an AMVESCAP
Ordinary Share on the date the Trustee receives the applicable Conversion
Notice. The AMVESCAP Share Value will be equal to the AMVESCAP Share Rate
multiplied by the Current Market Price of an AMVESCAP Ordinary Share on the date
the Trustee receives the applicable Conversion Notice. The AMVESCAP Share Rate
is subject to adjustment upon the occurrence of certain events specified in the
Indenture. The Corporation has the option by notifying the Trustee and the
Holder, in lieu of delivering Exchangeable Shares upon a conversion of
Debentures, to pay the Conversion Value of the Debentures tendered for
conversion in cash.

         The Corporation will send to the Holders of Debentures, at least 10
Business Days and not more than 20 Business Days prior to the maturity of the
Debentures, a notice (the "MATURITY NOTICE") which will provide such Holders
with the following options:

         (a)      to convert their Debentures to Exchangeable Shares, only if
                  the AMVESCAP Share Value at maturity is greater than or equal
                  to $1,000, subject to the right of the Corporation to pay the
                  Conversion Value in cash;

         (b)      to convert their Debentures to Exchangeable Shares, whether or
                  not the AMVESCAP Share Value at maturity exceeds $1,000,
                  subject to the right of the Corporation to pay the Conversion
                  Value in cash; or

         (c)      to receive payment of the principal amount of the Debentures
                  in cash, subject to the exercise by the Corporation of the
                  Share Repayment Right;

it being understood, in each case, that the accrued interest, if any, shall be
paid in cash.

         In order to select one of the options, Debentureholders will be
required to deliver to the Trustee before the close of business (in the City of
Toronto, Ontario) on the Business Day that is three Business Days prior to
maturity (the "DETERMINATION DATE") a duly completed exercise notice in
prescribed form. Holders of Debentures who do not deliver a duly completed
exercise notice at or before the close of business (in the City of Toronto,
Ontario) on the Determination Date will be deemed to have selected option (a)
and, unless the Corporation has exercised its right to pay the Conversion Value
in cash, the Debentures held by such Holders will automatically be converted
into Exchangeable Shares, if the AMVESCAP Share Value at maturity is greater
than or equal to $ 1,000. The Corporation shall specify in the Maturity Notice
whether it will deliver Exchangeable Shares on conversion of the Debentures or,
in lieu of delivering Exchangeable Shares on conversion, elects to pay the
Conversion Value in cash for Debentures tendered for conversion under option (a)
or (b), and whether, if the Holder selects option (c), the Corporation, in lieu
of paying cash on maturity, elects to exercise the Share Repayment Right and
deliver Exchangeable Shares.


<PAGE>   80
                                      -4-


         No fractional Exchangeable Shares will be delivered to the holders of
Debentures upon conversion, if the Redemption Amount is satisfied by the
delivery of Exchangeable Shares or if the Corporation exercises the Share
Repayment Right, but in lieu thereof, the Corporation will make an equivalent
cash payment.

         Subject to regulatory requirements and provided no Event of Default has
occurred and is continuing, the Corporation may purchase Debentures in the open
market or by tender or private contract at any price. Debentures purchased or
redeemed by the Corporation shall be cancelled and shall not be reissued.

         In all cases, if taxes are required to be deducted or withheld from a
payment in cash payable to a Holder or from Exchangeable Shares to be delivered
to a Holder (including, without limitation, Exchangeable Shares issued as a
result of the conversion of a Debenture at the option of the Holder or as a
result of the redemption of a Debenture before maturity at the option of the
Corporation), such Holder will receive such payment less all such applicable
taxes.

         The Indenture contains provisions for the holding of meetings of
Debentureholders and rendering certain resolutions passed at such meetings by
the Holders of the majority in aggregate principal amount of the Debentures
represented at the meeting and voted on such resolutions binding upon all
Debentureholders, subject to the provisions of the Indenture.

         This Debenture may only be transferred upon compliance with the
conditions precedent in the Indenture on the register kept at the principal
office of the Trustee in the City of Toronto, Ontario and may be exchanged at
such place, by the registered Holder hereof or its executors or administrators
or other legal representatives or its or their attorney duly appointed by an
instrument in writing in form and execution satisfactory to the Trustee, and
upon compliance with such reasonable requirements as the Trustee may prescribe,
and such transfer shall be duly noted thereon by the Trustee. Neither the
Corporation nor the Trustee nor any registrar shall be required to transfer or
exchange any Debentures on any Interest Payment Date or Redemption Date or for a
period of 15 Business Days preceding any Interest Payment Date (as defined in
the Indenture) or Redemption Date.

         This Debenture shall not become obligatory for any purpose until it
shall have been certified by the Trustee for the time being under the Indenture.

         The Holder of this Debenture, by receiving and holding same, hereby
accepts and agrees to be bound by the terms, and to be entitled to the benefits
of this Debenture and of the Indenture and confirms the appointment of the
Trustee and of the Indenture, the whole in accordance with and subject to the
respective provisions thereof.

         IN WITNESS WHEREOF AMVESCAP INC. has caused this Debenture to be signed
by its President and Secretary.


<PAGE>   81
                                      -5-


         DATED as of the 1st day of August, 2000.

                                       AMVESCAP INC.

                                       By:
                                          --------------------------------------
                                          President


                                       By:
                                          --------------------------------------
                                          Secretary



                              TRUSTEE'S CERTIFICATE

         This Debenture is one of the AMVESCAP Equity Subordinated Debentures
referred to in the Indenture within mentioned.


                                       CIBC MELLON TRUST COMPANY,
                                       Trustee

                                       By:
                                          --------------------------------------
                                          Authorized Signing Officer


<PAGE>   82
                                      -6-

--------------------------------------------------------------------------------
                           CERTIFICATE OF ENTITLEMENT

This Certificate is one of the duly authorized certificates of the Corporation
designated as its Certificates of Entitlement (the "CERTIFICATES") issued in
accordance with the Voting and Exchange Trust Agreement between AMVESCAP INC.
(the "CORPORATION"), AMVESCAP PLC and the Trustee designated thereunder
concurrently with the issuance of the AMVESCAP Equity Subordinated Debentures
(the "DEBENTURES") of the Corporation. This Certificate and the attached
Debenture(s) may be transferred and surrendered only together. The Voting and
Exchange Trust Agreement provides that upon presentation of this Certificate
together with the surrender of the attached Debenture(s), the holder of this
Certificate shall be entitled to become, for all purposes, a "Beneficiary" under
the terms of the Voting and Exchange Trust Agreement to the extent that the
holder becomes the registered holder of any Exchangeable Shares in connection
with the surrender of the attached Debenture(s).

A copy of the Voting and Exchange Trust Agreement is on file at the registered
office of the Corporation in Halifax, Nova Scotia.

BY WITNESS WHEREOF, the Corporation has caused this instrument to be duly
executed.



                                  AMVESCAP INC.



By:                                         By:
   --------------------------------            ---------------------------------
              PRESIDENT                                    SECRETARY
--------------------------------------------------------------------------------


The Form of Assignment, Retraction Request and Conversion Notice (collectively,
the "FORMS") are attached to this Debenture. The holder of this Debenture should
contact the office of CIBC Mellon Trust Company in Toronto in order to obtain a
copy of the Forms should they become detached from this Debenture.


<PAGE>   83
                                      -7-


                               FORM OF ASSIGNMENT

         FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers
unto __________________________________________, whose address and social
insurance number, if applicable, are set forth below, this Debenture (or
$________ principal amount hereof*) of AMVESCAP Inc. standing in the name(s) of
the undersigned in the register maintained by the Trustee on behalf of the
Corporation with respect to such Debenture and does hereby irrevocably authorize
and direct the Trustee to transfer such Debenture in such register, with full
power of substitution in the premises.

Dated:
      --------------------------------------------------------------------------

Address of Transferee:
                      ----------------------------------------------------------

(Street Address, City, Province and Postal Code)
                                                --------------------------------

Social Insurance Number of Transferee, if applicable:
                                                     ---------------------------

*If less than the full principal amount of the within Debenture is to be
transferred, indicate in the space provided the principal amount (which must be
$1,000 or an integral multiple thereof) to be transferred.

1.       The signature(s) to this assignment must correspond with the name(s) as
         written upon the face of this Debenture in every particular without
         alteration or any change whatsoever. The signature(s) must be
         guaranteed by a Canadian chartered bank or trust company or by a member
         firm of a recognized stock exchange in Canada. Notarized or witnessed
         signatures are not acceptable as guaranteed signatures.

2.       The registered holder of this Debenture is responsible for the payment
         of any documentary, stamp or other transfer taxes that may be payable
         in respect of the transfer of this Debenture.

Signature of Guarantor:

-----------------------------        -------------------------------------------
Authorized Officer                   Signature of transferring registered holder




-----------------------------
Name of Institution


<PAGE>   84
                                      -8-


                                CONVERSION NOTICE

TO:               AMVESCAP INC.
                  c/o CIBC Mellon Trust Company
                  199 Bay Street
                  Commerce Court West
                  Securities Level
                  Toronto, Ontario, Canada
                  M5L 1G9

NOTE:             All capitalized terms used herein have the meanings ascribed
                  thereto in the Indenture mentioned below, unless otherwise
                  indicated.

         Subject to the right of the Corporation to pay the Conversion Value in
cash, the undersigned registered holder of the attached Debentures irrevocably
elects to convert such Debentures (or $_____________________ principal amount
thereof*) in accordance with the terms of the Indenture referred to in such
Debentures on _______________ [THE DEBENTUREHOLDER MUST SPECIFY THE DATE UPON
WHICH IT WANTS THE CONVERSION TO BE EFFECTIVE WHICH CANNOT BE LESS THAN FOUR
BUSINESS DAYS OR MORE THAN 15 BUSINESS DAYS FROM THE DAY THE TRUSTEE RECEIVES
THIS CONVERSION NOTICE AND IF THIS CONVERSION NOTICE IS RECEIVED BY THE TRUSTEE
AFTER 4:30 P.M. (TORONTO TIME) ON ANY DAY IT WILL BE DEEMED TO HAVE BEEN
RECEIVED BY THE TRUSTEE ON THE NEXT BUSINESS DAY]. The undersigned registered
holder of such Debentures tenders herewith such Debentures, and, if applicable,
directs that the Exchangeable Shares of AMVESCAP Inc. issuable upon a conversion
be issued and delivered to the person indicated below. (If Exchangeable Shares
are to be issued in the name of a person other than the holder, all requisite
transfer taxes must be tendered by the undersigned).

Dated:
      ----------------------------          ------------------------------------
                                            (Signature of Registered Holder)

*        If less than the full principal amount of the Debentures, indicate in
         the space provided the principal amount (which must be $1,000 or
         integral multiples thereof).

Note:             If Exchangeable Shares are to be issued in the name of a
                  person other than the holder, the signature must be guaranteed
                  by a chartered bank, a trust company or a member firm of a
                  recognized stock exchange in Canada.

(Print name in which Exchangeable Shares are to be issued, delivered and
registered)

Name
    -----------------------------------


---------------------------------------     ------------------------------------
(Address)                                   (City, Province and Postal Code)

Name of guarantor:
                  ------------------------------------------


Authorized signature:
                     ---------------------------------------


<PAGE>   85
                                      -9-


[RETRACTION REQUEST TO BE COMPLETED ONLY IF THE DEBENTUREHOLDER WISHES TO HAVE
THE CORPORATION IMMEDIATELY REDEEM ALL OR ANY OF THE EXCHANGEABLE SHARES THE
DEBENTUREHOLDER RECEIVES UPON CONVERSION OF THIS DEBENTURE. THIS RETRACTION
REQUEST IS SUBJECT TO THE CORPORATION'S OVERRIDING RIGHT TO ELECT TO PAY THE
CONVERSION VALUE IN CASH IN LIEU OF DELIVERING EXCHANGEABLE SHARES ON
CONVERSION.]

                               RETRACTION REQUEST

To: AMVESCAP Inc. (the "Corporation") and AVZ Callco Inc. ("Callco")

         This notice is given pursuant to Section 6 of the provisions (the
"SHARE PROVISIONS") attaching to the Exchangeable Shares issuable upon
conversion of this Debenture and all capitalized words and expressions used in
this notice that are not defined in the Indenture but are defined in the Share
Provisions have the meanings ascribed to such words and expressions in such
Share Provisions.

         The undersigned hereby notifies the Corporation that, provided (i) the
Corporation has not exercised its right to pay the Conversion Value in cash, and
(ii) the Retraction Call Right referred to below has not been exercised, the
undersigned desires to have the Corporation redeem in accordance with Section 6
of the Share Provisions:

[ ]        all share(s) issuable upon conversion of this Debenture; or

[ ]        _______ share(s) only issuable upon conversion of this Debenture.

         The undersigned hereby notifies the Corporation that the Retraction
Date shall be _____________________.

NOTE:             The Retraction Date must be a Business Day and must not be
                  less than 10 Business Days nor more than 15 Business Days
                  after the Conversion Date. If no such Business Day is
                  specified above, the Retraction Date shall be deemed to be the
                  15th Business Day after the Conversion Date.

         The undersigned acknowledges the overriding Retraction Call Right of
Callco to purchase all but not less than all the Retracted Shares from the
undersigned and that this notice is and shall be deemed to be a revocable offer
by the undersigned to sell the Retracted Shares to Callco in accordance with the
Retraction Call Right on the Retraction Date for the Purchase Price and on the
other terms and conditions set out in section 6(3) of the Share Provisions. This
Retraction Request, and this offer to sell the Retracted Shares to Callco, may
be revoked and withdrawn by the undersigned only by notice in writing given to
the Corporation at any time before the close of business on the Business Day
immediately preceding the Retraction Date.


<PAGE>   86
                                      -10-


         The undersigned acknowledges that if, as a result of solvency
provisions of applicable law, the Corporation is unable to redeem all of the
Retracted Shares, the Retracted Shares will be automatically exchanged pursuant
to the Voting and Exchange Trust Agreement so as to require the Guarantor to
purchase the unredeemed Retracted Shares.

         The undersigned hereby represents and warrants to Callco and the
Corporation that the undersigned:

[ ]      is

                           (select one)

[ ]      is not

a non-resident of Canada for purposes of the Income Tax Act (Canada). THE
UNDERSIGNED ACKNOWLEDGES THAT IN THE ABSENCE OF AN INDICATION THAT THE
UNDERSIGNED IS NOT A NON-RESIDENT OF CANADA, WITHHOLDING ON ACCOUNT OF CANADIAN
TAX MAY BE MADE FROM AMOUNTS PAYABLE TO THE UNDERSIGNED ON THE REDEMPTION OR
PURCHASE OF THE RETRACTED SHARES.

[ ]      The undersigned hereby represents and warrants to Callco and the
Corporation that the undersigned is not a person within the United States of
America, its territories or possessions or any state thereof, or the District of
Columbia (collectively, the "United States") or a U.S. person (within the
meaning of Regulation S under the United States Securities Act of 1933, as
amended) and is not making this Retraction Request for the account or benefit of
a person within the United States or such a U.S. person.

         The undersigned hereby represents and warrants to Callco and the
Corporation that the undersigned (i) has good title to, and owns, this
Debenture, free and clear of all liens, claims and encumbrances, and (ii) will
have good title to, and own, the share(s) issuable upon conversion of this
Debenture to be acquired by Callco or the Corporation, as the case may be, free
and clear of all liens, claims and encumbrances.


--------------     ------------------------------     --------------------------
(Date)               (Signature of Shareholder)        (Guarantee of Signature)

         [ ]      Please check box if the certificates for AMVESCAP Ordinary
         Shares and any cheque(s) resulting from the retraction or purchase of
         the Retracted Shares are to be held for pick-up by the Debentureholder
         from the Trustee, failing which such certificates and cheque(s) will be
         mailed to the last address of the Debentureholder as it appears on the
         Debenture register.


<PAGE>   87
                                      -11-


NOTE:             This panel must be completed and this certificate, together
                  with such additional documents and payments (including,
                  without limitation, any applicable Stamp Taxes) as the Trustee
                  may require, must be deposited with the Trustee. The
                  securities and any cheque(s) resulting from the retraction or
                  purchase of the Retracted Shares will be issued and registered
                  in, and made payable to, respectively, the name of the
                  Debentureholder as it appears on the Debenture register and
                  the certificates for AMVESCAP Ordinary Shares and any
                  cheque(s) resulting from such retraction or purchase will be
                  delivered to such Debentureholder as indicated above, unless
                  the form appearing immediately below is duly completed.

Date:
     -------------------

Name of Person in Whose Name Securities or Cheque(s)

Are to be Registered, Issued or Delivered (please print):

Street Address or P.O. Box:

Signature of Shareholder:

City, Province and Postal Code:

Signature Guaranteed by:

NOTE:             If this Retraction Request is for less than all of the shares
                  issuable upon conversion of this Debenture, a certificate
                  representing the remaining Exchangeable Share(s) issuable upon
                  conversion of this Debenture will be issued and registered in
                  the name of the Debentureholder as it appears on the Debenture
                  register.


<PAGE>   88


                                  SCHEDULE "B"

                            FORM OF REDEMPTION NOTICE

                                  AMVESCAP INC.

                     AMVESCAP EQUITY SUBORDINATED DEBENTURES

                                REDEMPTION NOTICE

TO:               Holders of AMVESCAP Equity Subordinated Debentures (the
                  "DEBENTURES") of AMVESCAP Inc. (the "CORPORATION")

NOTE:             All capitalized terms used herein have the meanings ascribed
                  thereto in the Indenture mentioned below, unless otherwise
                  indicated.

         Notice is hereby given pursuant to Section 3.3 of the Indenture dated
August 1, 2000 among the Corporation, CIBC Mellon Trust Company (the "TRUSTEE")
and AMVESCAP PLC ("AMVESCAP"), that [, SUBJECT TO THE SATISFACTION OF THE
CONDITION SET OUT IN THE FOLLOWING PARAGRAPH (THE "CONDITION")] the aggregate
principal amount of all Debentures outstanding will be redeemed as of o (the
"REDEMPTION DATE"), upon payment of a redemption amount of $o for each $1,000
principal amount of Debentures, being equal to the aggregate of (i) $1,200, plus
(ii) all accrued and unpaid interest on such $1,000 principal amount to but
excluding the Redemption Date (collectively, the "REDEMPTION AMOUNT").

         [THERE IS AN OFFER (THAT IS A TAKE-OVER BID OR ISSUER BID TO PURCHASE
AMVESCAP ORDINARY SHARES OR ANOTHER TRANSACTION WHICH HAS A SIMILAR EFFECT AND
ONE OF THE CONDITIONS TO THE COMPLETION OF SUCH PURCHASE PURSUANT TO SUCH BID OR
OTHER TRANSACTION IS THE REDEMPTION OF THE DEBENTURES) AND THIS NOTICE OF
REDEMPTION AND THE CORPORATION'S OBLIGATION PURSUANT TO THIS NOTICE TO REDEEM
ALL OF THE OUTSTANDING DEBENTURES IS SUBJECT TO COMPLETION OF SUCH OFFER.]

         [SUBJECT TO SATISFACTION OF THE CONDITION,] The Redemption Amount (less
any tax required by law to be deducted) will be payable upon presentation and
surrender of the Debentures called for redemption at the following corporate
office:

           [SET OUT ADDRESS OF PRINCIPAL CORPORATE OFFICE IN TORONTO]

The interest upon the principal amount of Debentures called for redemption shall
cease to be payable from and after the Redemption Date, unless payment of the
Redemption Amount shall not be made on presentation for surrender of such
Debentures at the above-mentioned corporate office on or after the Redemption
Date or prior to the setting aside of the Redemption Amount pursuant to the
Indenture.

         [PURSUANT TO SECTION 3.6 OF THE INDENTURE, THE CORPORATION HEREBY
IRREVOCABLY ELECTS TO SATISFY ITS OBLIGATION TO PAY TO HOLDERS OF DEBENTURES THE
REDEMPTION AMOUNT BY ISSUING AND DELIVERING TO THE HOLDERS THAT NUMBER OF FREELY
TRADEABLE EXCHANGEABLE


<PAGE>   89
                                      -2-


SHARES OBTAINED BY DIVIDING (i) THE REDEMPTION AMOUNT, BY (ii) 95% OF THE
CURRENT MARKET PRICE OF AN AMVESCAP ORDINARY SHARE ON THE DATE OF THIS
REDEMPTION NOTICE (THE "SHARE REDEMPTION RIGHT"). THE CURRENT MARKET PRICE OF
AMVESCAP ORDINARY SHARE IS $o.]

         [NO FRACTIONAL EXCHANGEABLE SHARES SHALL BE DELIVERED UPON THE EXERCISE
BY THE CORPORATION OF THE ABOVE-MENTIONED SHARE REDEMPTION RIGHT BUT, IN LIEU
THEREOF, THE CORPORATION SHALL PAY THE CASH EQUIVALENT THEREOF DETERMINED ON THE
BASIS OF THE CURRENT MARKET PRICE OF AN AMVESCAP ORDINARY SHARE ON THE DATE OF
THIS REDEMPTION NOTICE (LESS ANY TAX REQUIRED BY LAW TO BE DEDUCTED).]

         Neither the Corporation nor the Trustee nor any registrar shall be
required to transfer or exchange any Debentures on any Interest Payment Date or
Redemption Date or for a period of 15 Business Days preceding any Interest
Payment Date or Redemption Date.

         Debentureholders are reminded that, subject to and in accordance with
the provisions of the Indenture, their Debentures are convertible at any time
and from time to time. A Debentureholder wishing to convert its Debentures
should review the provisions of Article 4 of the Indenture and the terms and
conditions of its Debentures and the Conversion Notice (including, without
limitation, the Retraction Request forming part of such notice) printed on its
Debenture certificate.

         DATED as of the o day of o.

                                       AMVESCAP INC.

                                       By:
                                          --------------------------------------
                                          Authorized Signing Officer


<PAGE>   90


                                  SCHEDULE "C"

                          FORM OF NOTICE OF CONVERSION

                                CONVERSION NOTICE

TO:               AMVESCAP INC.
                  c/o CIBC Mellon Trust Company
                  199 Bay Street
                  Commerce Court West
                  Securities Level
                  Toronto, Ontario, Canada
                  M5L 1G9

NOTE:             All capitalized terms used herein have the meanings ascribed
                  thereto in the Indenture mentioned below, unless otherwise
                  indicated.

         Subject to the right of the Corporation to pay the Conversion Value in
cash, the undersigned registered holder of the attached Debentures irrevocably
elects to convert such Debentures (or $____________________ principal amount
thereof*) in accordance with the terms of the Indenture referred to in such
Debentures on _______________ [THE DEBENTUREHOLDER MUST SPECIFY THE DATE UPON
WHICH IT WANTS THE CONVERSION TO BE EFFECTIVE WHICH CANNOT BE LESS THAN FOUR
BUSINESS DAYS OR MORE THAN 15 BUSINESS DAYS FROM THE DAY THE TRUSTEE RECEIVES
THIS CONVERSION NOTICE AND IF THIS CONVERSION NOTICE IS RECEIVED BY THE TRUSTEE
AFTER 4:30 P.M. (TORONTO TIME) ON ANY DAY IT WILL BE DEEMED TO HAVE BEEN
RECEIVED BY THE TRUSTEE ON THE NEXT BUSINESS DAY]. The undersigned registered
holder of such Debentures tenders herewith such Debentures, and, if applicable,
directs that the Exchangeable Shares of AMVESCAP Inc. issuable upon a conversion
be issued and delivered to the person indicated below. (If Exchangeable Shares
are to be issued in the name of a person other than the holder, all requisite
transfer taxes must be tendered by the undersigned).

Dated:
      ----------------------------          ------------------------------------
                                              (Signature of Registered Holder)

*        If less than the full principal amount of the Debentures, indicate in
         the space provided the principal amount (which must be $1,000 or
         integral multiples thereof).

Note:             If Exchangeable Shares are to be issued in the name of a
                  person other than the holder, the signature must be guaranteed
                  by a chartered bank, a trust company or a member firm of a
                  recognized stock exchange in Canada.

(Print name in which Exchangeable Shares are to be issued, delivered and
registered)

Name
    -----------------------------------


<PAGE>   91
                                      -2-


---------------------------------------     ------------------------------------
(Address)                                   (City, Province and Postal Code)

Name of guarantor:
                  -----------------------------------------

Authorized signature:
                     --------------------------------------

[RETRACTION REQUEST TO BE COMPLETED ONLY IF THE DEBENTUREHOLDER WISHES TO HAVE
THE CORPORATION IMMEDIATELY REDEEM ALL OR ANY OF THE EXCHANGEABLE SHARES THE
DEBENTUREHOLDER RECEIVES UPON CONVERSION OF THIS DEBENTURE. THIS RETRACTION
REQUEST IS SUBJECT TO THE CORPORATION'S OVERRIDING RIGHT TO ELECT TO PAY THE
CONVERSION VALUE IN CASH IN LIEU OF DELIVERING EXCHANGEABLE SHARES ON
CONVERSION.]

                               RETRACTION REQUEST

To: AMVESCAP Inc. (the "Corporation") and AVZ Callco Inc. ("Callco")

         This notice is given pursuant to Section 6 of the provisions (the
"SHARE PROVISIONS") attaching to the Exchangeable Shares issuable upon
conversion of this Debenture and all capitalized words and expressions used in
this notice that are not defined in the Indenture but are defined in the Share
Provisions have the meanings ascribed to such words and expressions in such
Share Provisions.

         The undersigned hereby notifies the Corporation that, provided (i) the
Corporation has not exercised its right to pay the Conversion Value in cash, and
(ii) the Retraction Call Right referred to below has not been exercised, the
undersigned desires to have the Corporation redeem in accordance with Section 6
of the Share Provisions:

[ ]      all share(s) issuable upon conversion of this Debenture; or

[ ]      _______ share(s) only issuable upon conversion of this Debenture.

         The undersigned hereby notifies the Corporation that the Retraction
Date shall be _____________________.

NOTE:             The Retraction Date must be a Business Day and must not be
                  less than 10 Business Days nor more than 15 Business Days
                  after the Conversion Date. If no such Business Day is
                  specified above, the Retraction Date shall be deemed to be the
                  15th Business Day after the Conversion Date.

         The undersigned acknowledges the overriding Retraction Call Right of
Callco to purchase all but not less than all the Retracted Shares from the
undersigned and that this notice is and shall be deemed to be a revocable offer
by the undersigned to sell the Retracted Shares to Callco in accordance with the
Retraction Call Right on the Retraction Date for the Purchase Price and on the
other terms and conditions set out in section 6(3) of the Share Provisions. This
Retraction Request, and this offer to sell the


<PAGE>   92
                                      -3-


Retracted Shares to Callco, may be revoked and withdrawn by the undersigned only
by notice in writing given to the Corporation at any time before the close of
business on the Business Day immediately preceding the Retraction Date.

         The undersigned acknowledges that if, as a result of solvency
provisions of applicable law, the Corporation is unable to redeem all of the
Retracted Shares, the Retracted Shares will be automatically exchanged pursuant
to the Voting and Exchange Trust Agreement so as to require the Guarantor to
purchase the unredeemed Retracted Shares.

         The undersigned hereby represents and warrants to Callco and the
Corporation that the undersigned:

[ ]      is

                           (select one)

[ ]      is not

a non-resident of Canada for purposes of the Income Tax Act (Canada). THE
UNDERSIGNED ACKNOWLEDGES THAT IN THE ABSENCE OF AN INDICATION THAT THE
UNDERSIGNED IS NOT A NON-RESIDENT OF CANADA, WITHHOLDING ON ACCOUNT OF CANADIAN
TAX MAY BE MADE FROM AMOUNTS PAYABLE TO THE UNDERSIGNED ON THE REDEMPTION OR
PURCHASE OF THE RETRACTED SHARES.

[ ]      The undersigned hereby represents and warrants to Callco and the
Corporation that the undersigned is not a person within the United States of
America, its territories or possessions or any state thereof, or the District of
Columbia (collectively, the "United States") or a U.S. person (within the
meaning of Regulation S under the United States Securities Act of 1933, as
amended) and is not making this Retraction Request for the account or benefit of
a person within the United States or such a U.S. person.

         The undersigned hereby represents and warrants to Callco and the
Corporation that the undersigned (i) has good title to, and owns, this
Debenture, free and clear of all liens, claims and encumbrances, and (ii) will
have good title to, and own, the share(s) issuable upon conversion of this
Debenture to be acquired by Callco or the Corporation, as the case may be, free
and clear of all liens, claims and encumbrances.


--------------     ------------------------------     --------------------------
(Date)               (Signature of Shareholder)        (Guarantee of Signature)

         [ ]      Please check box if the certificates for AMVESCAP Ordinary
         Shares and any cheque(s) resulting from the retraction or purchase of
         the Retracted Shares are to be held for pick-up by the Debentureholder
         from the Trustee, failing which


<PAGE>   93
                                      -4-


         such certificates and cheque(s) will be mailed to the last address of
         the Debentureholder as it appears on the Debenture register.

NOTE:             This panel must be completed and this certificate, together
                  with such additional documents and payments (including,
                  without limitation, any applicable Stamp Taxes) as the Trustee
                  may require, must be deposited with the Trustee. The
                  securities and any cheque(s) resulting from the retraction or
                  purchase of the Retracted Shares will be issued and registered
                  in, and made payable to, respectively, the name of the
                  Debentureholder as it appears on the Debenture register and
                  the certificates for AMVESCAP Ordinary Shares and any
                  cheque(s) resulting from such retraction or purchase will be
                  delivered to such Debentureholder as indicated above, unless
                  the form appearing immediately below is duly completed.

Date:
     -------------------

Name of Person in Whose Name Securities or Cheque(s)

Are to be Registered, Issued or Delivered (please print):

Street Address or P.O. Box:

Signature of Shareholder:

City, Province and Postal Code:

Signature Guaranteed by:

NOTE:             If this Retraction Request is for less than all of the shares
                  issuable upon conversion of this Debenture, a certificate
                  representing the remaining Exchangeable Share(s) issuable upon
                  conversion of this Debenture will be issued and registered in
                  the name of the Debentureholder as it appears on the Debenture
                  register.


<PAGE>   94


                                 SCHEDULE "D-1"

                             FORM OF MATURITY NOTICE

                                  AMVESCAP INC.

                     AMVESCAP EQUITY SUBORDINATED DEBENTURES

                                 MATURITY NOTICE

TO:               Holders of AMVESCAP Equity Subordinated Debentures (the
                  "DEBENTURES") of AMVESCAP Inc. (the "CORPORATION")

NOTE:             All capitalized terms used herein have the meanings ascribed
                  thereto in the Indenture mentioned below, unless otherwise
                  indicated.

         Notice is hereby given pursuant to Section 4.3 of the Indenture dated
August 1, 2000 between the Corporation, CIBC Mellon Trust Company, as trustee
(the "TRUSTEE") and AMVESCAP PLC ("AMVESCAP"), that the Debentures will become
due and payable as of August 1, 2003 (the "MATURITY DATE") and that each $1,000
principal amount of Debentures will become convertible, at the option of the
holder thereof, on the Maturity Date, into the Conversion Number of Exchangeable
Shares then in effect. The Conversion Number of Exchangeable Shares on the
Maturity Date will be calculated as (i) the Conversion Value (being the lesser
of the AMVESCAP Share Value and $1,200) on such date divided by (ii) the Current
Market Price of an AMVESCAP Ordinary Shares on the Maturity Date. The AMVESCAP
Share Value on the Maturity Date will be equal to the product of the AMVESCAP
Share Rate and the Current Market Price of an AMVESCAP Ordinary Share on the
Maturity Date. The Current Market Price of an AMVESCAP Ordinary Share on the
Maturity Date shall be the quotient obtained by dividing (i) the aggregate of
the Daily Value of Trades for each day during the period of 20 consecutive
Trading Days ending not more than three Trading Days before such date, by (ii)
the aggregate volume of AMVESCAP Ordinary Shares used to calculate such Daily
Value of Trades.

         Each holder of Debentures has the following options in respect of the
maturity of the Debentures:

         (a)      to convert their Debentures to Exchangeable Shares, only if
                  the AMVESCAP Share Value on the Maturity Date is greater than
                  or equal to $1,000, subject to the right of the Corporation to
                  pay the Conversion Value in cash;

         (b)      to convert their Debentures to Exchangeable Shares, whether or
                  not the AMVESCAP Share Value on the Maturity Date exceeds
                  $1,000, subject to the right of the Corporation to pay the
                  Conversion Value in cash; or

         (c)      to receive payment of the principal amount of the Debentures
                  in cash, subject to the exercise by the Corporation of the
                  Share Repayment Right;


<PAGE>   95
                                      -2-


it being understood, in each case, that the accrued interest, if any, shall be
paid in cash.

In order to select one of the above-mentioned options a Holder will be required
to deliver to the Trustee at the following address:

                  [SET OUT ADDRESS OF THE APPROPRIATE ADDRESS]

before the close of business on the Business Day that is three Business Days
prior to the Maturity Date (the "DETERMINATION DATE"), an exercise notice in the
form annexed hereto duly completed and executed by such Holder or its executors
or administrators or other legal representatives or its or their attorney duly
appointed by instrument in form and execution satisfactory to the Trustee,
together with the Debentures to which such notice relates. A HOLDER WHO DOES NOT
DELIVER A DULY COMPLETED EXERCISE NOTICE AT OR BEFORE THE CLOSE OF BUSINESS ON
THE DETERMINATION DATE WILL BE DEEMED TO HAVE SELECTED OPTION (a) AND THE
DEBENTURES HELD BY SUCH HOLDERS WILL AUTOMATICALLY BE CONVERTED INTO
EXCHANGEABLE SHARES IF THE AMVESCAP SHARE VALUE AS OF THE MATURITY DATE IS
GREATER THAN OR EQUAL TO $1,000 [SUBJECT TO THE ELECTION BELOW MADE BY THE
CORPORATION TO PAY THE CONVERSION VALUE IN CASH].

         A Holder's selection of an option on the Determination Date should take
into account the Current Market Price of an AMVESCAP Ordinary Share on the
Maturity Date which may be more or less than the market price of an AMVESCAP
Ordinary Share on the Maturity Date. A HOLDER SELECTING OPTION (b) MAY BE ACTING
CONTRARY TO HIS OR HER ECONOMIC INTERESTS SINCE, IF THE AMVESCAP SHARE VALUE AT
MATURITY IS LESS THAN $1,000, A HOLDER OF DEBENTURES MAY RECEIVE A GREATER
AMOUNT UNDER OPTION (c).

         If a Holder selects option (a) or (b) and the Conversion Value (or any
portion thereof) is subject to withholding taxes on account of income tax, the
Corporation shall sell, or cause to be sold, through investment banks, brokers
or dealers selected by the Corporation, out of the Exchangeable Shares issued by
the Corporation for this purpose, such number of Exchangeable Shares that is
sufficient to cover the amount of taxes required to be withheld and shall remit
same, or cause same to be remitted, to the proper tax authorities within the
period of time prescribed for this purpose under applicable laws.

         Pursuant to Section 4.3(4) of the Indenture, the Corporation hereby
advises the Holders of Debentures that it [WILL DELIVER EXCHANGEABLE SHARES ON
THE CONVERSION OF THE DEBENTURES] [OR] [IRREVOCABLY ELECTS TO PAY TO HOLDERS OF
DEBENTURES WHO HAVE ELECTED OR ARE DEEMED TO HAVE ELECTED TO CONVERT THEIR
DEBENTURES INTO EXCHANGEABLE SHARES, AN AMOUNT IN CASH EQUAL TO THE CONVERSION
VALUE PER $1,000 PRINCIPAL AMOUNT OF DEBENTURES, LESS ANY TAX REQUIRED BY LAW TO
BE DEDUCTED,] and that it [WILL DELIVER TO HOLDERS OF DEBENTURES WHO HAVE
SELECTED OPTION (c) THAT NUMBER OF FREELY TRADEABLE EXCHANGEABLE SHARES EQUAL TO
THE NUMBER OBTAINED BY DIVIDING THE PRINCIPAL AMOUNT OF SUCH DEBENTURES BY 95%
OF THE CURRENT MARKET PRICE OF AN AMVESCAP ORDINARY SHARE ON THE MATURITY DATE.
IN THE EVENT THAT THE CORPORATION ELECTS TO ISSUE AND DELIVER EXCHANGEABLE
SHARES AS AFORESAID, UPON PRESENTATION AND SURRENDER OF THE DEBENTURES, THE
CORPORATION SHALL PAY OR CAUSE TO BE PAID IN CASH TO THE HOLDER ALL ACCRUED AND


<PAGE>   96
                                      -3-


UNPAID INTEREST TO THE MATURITY DATE, TOGETHER WITH THE CASH EQUIVALENT
REPRESENTING FRACTIONAL EXCHANGEABLE SHARES.]

         DATED as of the o day of o, 2003.

                                       AMVESCAP INC.

                                       By:
                                          --------------------------------------
                                          Authorized Signing Officer



<PAGE>   97

                                 SCHEDULE "D-2"

                       FORM OF EXERCISE NOTICE AT MATURITY

                                 EXERCISE NOTICE

TO:               AMVESCAP INC.

NOTE:             All capitalized terms used herein have the meanings ascribed
                  thereto in the Indenture mentioned below, unless otherwise
                  indicated.

         The undersigned registered holder of AMVESCAP Equity Subordinated
Debentures bearing Certificate No. o irrevocably elects (please check applicable
box to indicate your choice):

[ ]      (a)      to convert such Debentures to Exchangeable Shares (or $o
                  principal amount thereof*) only if the AMVESCAP Share Value on
                  the Maturity Date is greater than or equal to $1,000, subject
                  to the right of the Corporation to pay the Conversion Value in
                  cash; or

[ ]      (b)      to convert such Debentures to Exchangeable Shares (or $o
                  principal amount thereof*) whether or not the AMVESCAP Share
                  Value on the Maturity Date exceeds $1,000, subject to the
                  right of the Corporation to pay the Conversion Value in cash;
                  or

[ ]      (c)      to receive payment of the principal amount of such Debentures
                  (or $o principal amount thereof*) in cash, subject to exercise
                  by the Corporation of the Share Repayment Right;

it being understood, in each case, that the accrued interest, if any, shall be
paid in cash,

in accordance with the terms of the Indenture referred to in such Debenture and
tenders herewith such Debentures, and, if applicable, directs that the
Exchangeable Shares of the Corporation issuable and deliverable upon a
conversion or in satisfaction of the payment of the principal amount at the
Maturity Date be issued and delivered to the person indicated below. (If
Exchangeable Shares are to be issued in the name of a person other than the
holder, all requisite transfer taxes must be tendered by the undersigned.)

         A HOLDER WHO DOES NOT DELIVER A DULY COMPLETED EXERCISE NOTICE AT OR
BEFORE THE CLOSE OF BUSINESS ON THE DETERMINATION DATE WILL BE DEEMED TO HAVE
SELECTED OPTION (a) AND THE DEBENTURES HELD BY SUCH HOLDERS WILL AUTOMATICALLY
BE CONVERTED INTO EXCHANGEABLE SHARES IF THE AMVESCAP SHARE VALUE AS OF THE
MATURITY DATE IS GREATER THAN OR EQUAL TO $1,000 [SUBJECT TO THE ELECTION IN THE
MATURITY NOTICE MADE BY THE CORPORATION TO PAY THE CONVERSION VALUE IN CASH].


<PAGE>   98
                                      -2-


         A HOLDER SELECTING OPTION (b) MAY BE ACTING CONTRARY TO HIS OR HER
ECONOMIC INTERESTS SINCE, IF THE AMVESCAP SHARE VALUE AT MATURITY IS LESS THAN
$1,000, A HOLDER OF DEBENTURES MAY RECEIVE A GREATER AMOUNT UNDER OPTION (c).

Dated:
      ---------------------------------     ------------------------------------
                                              (Signature of Registered Holder)

*        If less than the full principal amount of the Debenture, indicate in
         the space provided the principal amount (which must be $1,000 or
         integral multiples thereof).

Note:             If Exchangeable Shares are to be issued in the name of a
                  person other than the holder, the signature must be guaranteed
                  by a chartered bank, a trust company or a member firm of a
                  recognized stock exchange in Canada.

(Print name in which Exchangeable Shares are to be issued, delivered and
registered)

Name
    -----------------------------------


---------------------------------------     ------------------------------------
(Address)                                   (City, Province and Postal Code)

Name of guarantor:
                  -----------------------------------------

Authorized signature:
                     --------------------------------------