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C L I F F O R D
C H A N C E                                                 [CHINESE CHARACTERS]

                                                                  CONFORMED COPY

                                                                     EXHIBIT 4.2

                                DATED 19 MAY 2003

                       MARCONI COMMUNICATIONS ASIA LIMITED
                                   AS COMPANY

                                  IN FAVOUR OF

                   THE LAW DEBENTURE TRUST CORPORATION P.L.C.
                               AS SECURITY TRUSTEE

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                                    DEBENTURE

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                                    CONTENTS

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<CAPTION>
CLAUSE                                                                                                   PAGE
<S>    <C>                                                                                               <C>
 1.    DEFINITIONS AND INTERPRETATION.................................................................     1

 2.    PAYMENT OF SECURED OBLIGATIONS.................................................................     5

 3.    FIXED CHARGES, ASSIGNMENTS AND FLOATING CHARGE.................................................     6

 4.    CRYSTALLISATION OF FLOATING CHARGE.............................................................     7

 5.    PERFECTION OF SECURITY.........................................................................     8

 6.    FURTHER ASSURANCE..............................................................................    10

 7.    NEGATIVE PLEDGE AND DISPOSALS..................................................................    11

 8.    SHARES.........................................................................................    11

 9.    ACCOUNTS.......................................................................................    12

10.    MONETARY CLAIMS................................................................................    13

11.    REAL PROPERTY..................................................................................    13

12.    INVESTMENTS: DELIVERY OF DOCUMENTS OF TITLE....................................................    14

13.    INTRA-GROUP LOAN CONTRACTS.....................................................................    14

14.    ENFORCEMENT OF SECURITY........................................................................    14

15.    EXTENSION AND VARIATION OF CONVEYANCING AND PROPERTY ORDINANCE.................................    15

16.    APPOINTMENT OF RECEIVER........................................................................    15

17.    POWERS OF RECEIVER.............................................................................    16

18.    APPLICATION OF MONEYS..........................................................................    17

19.    PROTECTION OF PURCHASERS.......................................................................    17

20.    POWER OF ATTORNEY..............................................................................    17

21.    EFFECTIVENESS OF SECURITY......................................................................    18

22.    RELEASE OF SECURITY............................................................................    19

23.    SET-OFF........................................................................................    20

24.    SUBSEQUENT SECURITY INTERESTS..................................................................    20

25.    CURRENCY INDEMNITY.............................................................................    20

26.    ASSIGNMENT.....................................................................................    20

27.    NOTICES........................................................................................    21

28.    EXPENSES, COSTS AND TAXES......................................................................    21

29.    PAYMENTS FREE OF DEDUCTION.....................................................................    21

30.    DISCRETION AND DELEGATION......................................................................    22

31.    PERPETUITY PERIOD..............................................................................    22
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<TABLE>
<S>    <C>                                                                                                <C>
32.    GOVERNING LAW..................................................................................    22

33.    JURISDICTION...................................................................................    22

34.    COUNTERPARTS...................................................................................    23

SCHEDULE 1 FORM OF NOTICE OF ASSIGNMENT OF INTRA-GROUP LOAN...........................................    24

SCHEDULE 2............................................................................................    27

       Part A Form of Notice of Charge to Landlords...................................................    27

       Part B Form of Notice of Charge Over Account...................................................    29

       Part C Form of Notice of Charge over Monetary Claims...........................................    32

SCHEDULE 3 ADDITIONAL POWERS OF RECEIVER..............................................................    35

SCHEDULE 4 DETAILS OF SHARES..........................................................................    38
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THIS DEBENTURE is made on 19 May 2003

BY

(1)      MARCONI COMMUNICATIONS ASIA LIMITED registered in Hong Kong with
         company number 021763 (the "COMPANY") in favour of

(2)      THE LAW DEBENTURE TRUST CORPORATION P.L.C. as security trustee for the
         Secured Creditors on the terms and conditions set out in the Security
         Trust and Intercreditor Deed (the "SECURITY TRUSTEE" which expression
         shall include any person for the time being appointed as trustee or as
         an additional trustee for the purpose of, and in accordance with, the
         Security Trust and Intercreditor Deed).

IT IS AGREED as follows:

1.       DEFINITIONS AND INTERPRETATION

1.1      DEFINITIONS

         Terms defined in the Security Trust and Intercreditor Deed shall,
         unless otherwise defined in this Debenture, have the same meaning when
         used in this Debenture and in addition:

         "ACCOUNTS" means any credit balance from time to time on any account
         opened or maintained by the Company with any financial institution and
         all Related Rights.

         "CHARGED PROPERTY" means all the assets of the Company which from time
         to time are the subject of the security created or expressed to be
         created in favour of the Security Trustee by or pursuant to this
         Debenture.

         "COLLATERAL RIGHTS" means all rights, powers and remedies of the
         Security Trustee provided by or pursuant to this Debenture or by law.

         "ENFORCEMENT EVENT" has the meaning given to such term in the Security
         Trust and Intercreditor Deed.

         "EXISTING PERFORMANCE BONDS" means surety bonds, appeal bonds, bid
         bonds, performance bonds, letters of credit, bank guarantees or other
         obligations of a like nature issued by a bank, insurance company or
         other financial institution on behalf of Marconi Corporation or any of
         its Subsidiaries in existence on the Issue Date and not issued pursuant
         to an Interim Bonding Facility until such bonds, letters of credit,
         guarantees or obligations expire, terminate or are cancelled.

         "GROUP" means Marconi Corporation and its Subsidiaries for the time
         being.

         "INSOLVENCY EVENT OF DEFAULT" means any Insolvency Event which is also
         an Event of Default.

         "INSURANCE POLICY" means any policy of insurance in which the Company
         may from time to time have an interest and all Related Rights.

         "INTELLECTUAL PROPERTY" means all industrial and intellectual property
         rights whether registered or not including pending applications for
         registration of such rights and the

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         right to apply for registration of such rights including but not
         limited to Patents (as defined in the Indentures), utility models,
         design patents, registered designs, design rights, trade and service
         marks, copyrights (including copyright and equivalent rights in
         computer software), rights in inventions, technical information, rights
         in know-how, business names, database rights, processes, models,
         formulae and experiments and all rights of equivalent or similar effect
         to any of those which may subsist anywhere in the world and all Related
         Rights.

         "INTERIM BONDING FACILITY DOCUMENTS" means the Bonding Documents
         referred to in the Interim Bonding Facility Letter.

         "INTERIM BONDING FACILITY LETTER" means the facility letter dated 10
         May 2002, as amended on 24 October 2002, between HSBC Bank plc,
         Barclays Bank PLC, JPMorgan Chase Bank and Marconi Bonding Limited in
         an amount up to L150,000,000 (or the equivalent in other currencies)
         for the issuance of bonds, guarantees, letters of credit, indemnities
         and similar instruments.

         "INTRA-GROUP LOAN CONTRACTS" means any contracts between the Company
         and any member of the Group pursuant to which the Company makes
         available intra-Group loans to such member of the Group and all Related
         Rights.

         "INVESTMENTS" means:

         (a)      any stocks, shares, debentures, securities and certificates of
                  deposit (but not including the Shares);

         (b)      all interests in collective investment schemes; and

         (c)      all warrants, options and other rights to subscribe or acquire
                  any of the investments described in (a) and (b),

         in each case whether held directly by or to the order of the Company or
         by any trustee, nominee, fiduciary or clearance system on its behalf
         and all Related Rights (including all rights against any such trustee,
         nominee, fiduciary or clearance system).

         "MARCONI CORPORATION" means Marconi Corporation plc (registered in
         England and Wales with company number 00067307).

         "MONETARY CLAIMS" means any book and other debts and monetary claims
         owing to the Company and any proceeds thereof including, without
         limitation, any claims or sums of money deriving from or in relation to
         any Intellectual Property, the proceeds of any Insurance Policy, any
         court order or judgment, any contract or agreement to which the Company
         is a party and any other assets, property, rights or undertaking of the
         Company and all Related Rights.

         "NEW BONDING FACILITY AGREEMENT" means the L50 million committed
         revolving bonding facility agreement dated 27 March 2003 among Marconi
         Corporation, Marconi Bonding Limited, HSBC Bank plc as agent and
         security trustee, the lenders described thereunder and certain other
         Subsidiaries providing for the issuance of surety bonds, appeal bonds,
         bid bonds, performance bonds, letters of credit, bank guarantees or
         other obligations of a

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         like nature on behalf of Marconi Corporation and/or any Subsidiary, as
         such agreement may be amended, extended, supplemented or otherwise
         modified from time to time (including, without limitation, any
         successive amendments, extensions, supplements or other modifications
         of the foregoing).

         "NOTICE OF ASSIGNMENT" means a notice of assignment in substantially
         the form set out in Schedule 1.

         "NOTICE OF CHARGE" means a notice of charge in substantially a form set
         out in Schedule 2.

         "REAL PROPERTY" means:

         (a)      any real or immovable property;

         (b)      any buildings, fixtures, fittings, fixed plant or machinery
                  from time to time situated on or forming part of such real or
                  immovable property; and

         (c)      any present or future real or immovable property in which the
                  Company has an interest,

         and includes all Related Rights.

         "RECEIVER" means a receiver or receiver and manager of the whole or any
         part of the Charged Property.

         "RELATED RIGHTS" means, in relation to any asset:

         (a)      the proceeds of sale or assignment of all or any part of that
                  asset;

         (b)      all rights under any licence, agreement for sale or agreement
                  for lease in respect of that asset;

         (c)      all rights, benefits, claims, contracts, warranties, remedies,
                  security, indemnities or covenants for title in respect of
                  that asset; and

         (d)      any moneys and proceeds paid or payable in respect of that
                  asset including, but not limited to royalties, licence
                  payments, awards of damages and payments made pursuant to
                  settlement agreements in respect of that asset.

         "SECURED OBLIGATIONS" means all present and future indebtedness,
         liabilities and obligations (for the avoidance of doubt, including any
         liabilities and obligations which have been cash-collateralised by the
         Company) at any time of the Company under the Relevant Documents, both
         actual and contingent and whether incurred solely or jointly or in any
         other capacity together with any of the following matters relating to
         or arising in respect of those liabilities and obligations:

         (a)      any refinancing, novation, deferral or extension;

         (b)      any obligation relating to any increase in the amount of such
                  obligations;

         (c)      any claim for damages or restitution; and

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         (d)      any claim as a result of any recovery by the Company of a
                  payment or discharge, or non-allowability, on the grounds of
                  preference,

         and any amounts that would be included in any of the above but for any
         discharge, non-provability or unenforceability of those amounts in any
         insolvency or other proceedings (including interest accruing after the
         commencement of any insolvency or other proceedings).

         "SECURITY TRUST AND INTERCREDITOR DEED" means the security trust and
         intercreditor deed dated on or about the date hereof between, amongst
         others, the Security Trustee, Marconi Corporation and other obligors,
         Law Debenture Trust Company of New York as senior note trustee and
         JPMorgan Chase Bank as junior note trustee.

         "SHARES" means all of the shares in the companies set out in Schedule 4
         (Details of Shares) held by, to the order or on behalf of the Company
         at any time and all Related Rights.

         "SUBSIDIARY" means a subsidiary within the meaning of Section 736 of
         the Companies Act 1985 of the United Kingdom, as amended by Section 144
         of the Companies Act 1989 of the United Kingdom.

         "TANGIBLE MOVEABLE PROPERTY" means any plant, machinery, office
         equipment, computers, vehicles and other chattels (excluding any for
         the time being forming part of the Company's stock in trade or work in
         progress) and all Related Rights.

         "TEMPORARY BONDING FACILITY DOCUMENTS" means the Bonding Documents
         referred to in the Temporary Bonding Facility Letter.

         "TEMPORARY BONDING FACILITY LETTER" means the facility letter dated 8
         February 2002 between HSBC Bank plc, Barclays Bank PLC and Marconi
         Bonding Limited in an amount up to L50,000,000 (or equivalent in other
         currencies) for the issuance of bonds, guarantees, letters of credit,
         indemnities and similar instruments.

1.2      INTERPRETATION

         In this Debenture:

         1.2.1    the rules of interpretation contained in clause 1.2
                  (Interpretation) of the Security Trust and Intercreditor Deed
                  shall apply to the construction of this Debenture;

         1.2.2    "continuing" in relation to an Enforcement Event, shall be
                  construed as a reference to an acceleration of any Secured
                  Obligation (other than Secured Obligations arising under the
                  New Bonding Facility Agreement) where such acceleration has
                  not been rescinded in writing or a declaration that the
                  Secured Obligations (other than Secured Obligations arising
                  under the New Bonding Facility Agreement) are prematurely due
                  and payable (other than solely as a result of it becoming
                  unlawful for a Secured Creditor to perform its obligations
                  under the Relevant Documents) where such declaration has not
                  been revoked in writing or any failure by an Obligor to pay
                  any principal amount in respect of any Secured Obligations
                  (other than Secured Obligations arising under the New Bonding
                  Facility Agreement) whether on maturity or otherwise which has
                  not

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                  been remedied or waived in writing. For the purposes of this
                  sub-clause 1.2.2, the definition of "Secured Obligation" shall
                  have the same meaning as in the Security Trust and
                  Intercreditor Deed.

         1.2.3    any reference to the "SECURITY TRUSTEE", the "COMPANY" or the
                  "SECURED CREDITORS" shall be construed so as to include its or
                  their (and any subsequent) successors in title and any
                  permitted assignees and transferees in accordance with their
                  respective interests; and

         1.2.4    references in this Debenture to any Clause or Schedule shall
                  be to a clause or schedule contained in this Debenture.

1.3      HONG KONG

         In this Debenture, "Hong Kong" means the Hong Kong Special
         Administrative Region of the People's Republic of China.

1.4      SECURITY TRUST AND INTERCREDITOR DEED

         The parties hereto each acknowledge that the Security Trustee, when
         acting hereunder, shall be acting in accordance with and subject to the
         terms of the Security Trust and Intercreditor Deed.

1.5      CONFLICT

         Notwithstanding any provision to the contrary contained herein, the
         parties agree that this Debenture is subject in all respects to the
         terms of the Security Trust and Intercreditor Deed and for the
         avoidance of doubt, in the event of any inconsistency, the provisions
         of the Security Trust and Intercreditor Deed shall prevail.

2.       PAYMENT OF SECURED OBLIGATIONS

2.1      COVENANT TO PAY

         The Company hereby covenants with the Security Trustee as trustee for
         the Secured Creditors that it shall on demand of the Security Trustee
         discharge all the Secured Obligations and the Company shall pay to the
         Security Trustee when due and payable every sum at any time owing, due
         or incurred by the Company to the Security Trustee (whether for its own
         account or as trustee for the Secured Creditors) or any of the other
         Secured Creditors in respect of any such liabilities PROVIDED THAT,
         notwithstanding any provision to the contrary contained herein, neither
         such covenant nor the security constituted by this Debenture nor any
         other provisions of this Debenture shall extend to or include or be
         taken as creating security for nor shall the security constituted by
         this Debenture extend to secure any liability or sum which would, but
         for this proviso, cause such covenant, security or provision to be
         unlawful or prohibited by or otherwise to contravene any applicable law
         (including, without limitation, Section 47A of the Companies Ordinance
         (Cap.32)).

2.2      INTEREST ON DEMANDS

         If the Company fails to pay any sum on the due date for payment of that
         sum the Company shall pay interest on such sum (before and after any
         judgment and to the extent interest at a default rate is not otherwise
         being paid on such sum) from the date of demand until the date of
         payment calculated on a daily basis at the rate determined in

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         accordance with the provisions of Clause 18.4 (Interest on Demands) of
         the Security Trust and Intercreditor Deed.

3.       FIXED CHARGES, ASSIGNMENTS AND FLOATING CHARGE

3.1      FIXED CHARGES

         The Company as beneficial owner hereby charges in favour of the
         Security Trustee as trustee for the Secured Creditors as security for
         the payment and discharge of the Secured Obligations, by way of first
         fixed charge all of the Company's right, title and interest from time
         to time in and to each of the following assets:

         3.1.1    the Tangible Moveable Property;

         3.1.2    any goodwill;

         3.1.3    all rights in relation to the uncalled capital of the Company;

         3.1.4    the Shares, all dividends, interest and other monies payable
                  in respect of the Shares and all Related Rights (whether
                  derived by way of redemption, bonus, preference, option,
                  substitution, conversion or otherwise); and

         3.1.5    all Monetary Claims deriving from or in relation to any
                  Intellectual Property,

         provided that, where any contract, instrument or agreement in respect
         of any such asset or, where appropriate, any consent obtained
         thereunder contains an effective prohibition against or restriction on
         the granting of a first fixed charge over such asset, the first fixed
         charge hereby created shall take effect only to the greatest extent
         thereby permitted. The Company undertakes to use commercially
         reasonable efforts to ensure that any asset of any of the categories
         described in sub clauses 3.1.1 to 3.1.5 which is or is to be the
         subject of any contract, instrument or agreement which comes into being
         on or after the date of this Debenture shall be capable of being the
         subject of a first fixed charge in favour of the Security Trustee.

3.2      ASSIGNMENTS

         The Company as beneficial owner hereby assigns to the Security Trustee
         as trustee for the Secured Creditors as security for the payment and
         discharge of the Secured Obligations all the Company's right, title and
         interest from time to time in and to each of the Intra-Group Loan
         Contracts (having already obtained any necessary consent to such
         assignment from any third party).

3.3      FLOATING CHARGE

         The Company as beneficial owner hereby charges in favour of the
         Security Trustee as trustee for the Secured Creditors as security for
         the payment and discharge of the Secured Obligations by way of first
         floating charge the whole of the Company's undertaking and assets
         (including, but not limited to the Real Property, the Accounts, the
         Insurance Policies, the Intellectual Property, the Monetary Claims and
         the Investments), present and future, other than any assets validly and
         effectively charged or assigned (whether at law or in equity) by way of
         fixed security under the laws of Hong Kong, or of the jurisdiction in
         which that asset is situated, in favour of the Security Trustee as
         security for the Secured Obligations, provided that, where any
         contract, instrument or

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         agreement in respect of any such undertaking or asset or, where
         appropriate, any consent obtained thereunder contains an effective
         prohibition against or restriction on the granting of a first floating
         charge over such undertaking or asset, the first floating charge hereby
         created shall take effect only to the greatest extent thereby
         permitted. The Company undertakes to use commercially reasonable
         efforts to ensure that any of the Company's undertaking and assets
         described in this Clause 3.3 which is or is to be the subject of any
         contract, instrument or agreement which comes into being on or after
         the date of this Debenture shall be capable of being the subject of a
         first floating charge in favour of the Security Trustee.

3.4      CASH COLLATERAL

         The security created by Clause 3.3 (Floating Charge) over the Accounts
         shall take effect subject to, and shall not restrict the ability of the
         Company to create, any (a) security or (b) other arrangement under
         which money or claims to, or the benefit of, a bank or other account
         may be applied, set-off, made subject to a combination of accounts or
         otherwise subject to time deposit arrangements or other flawed asset
         rights (whether or not such security is or is to be created on, before
         or after the date of this Debenture) which secures obligations under
         and/or in respect of:

         3.4.1    the Interim Bonding Facility Documents;

         3.4.2    the Temporary Bonding Facility Documents;

         3.4.3    the New Bonding Facility Agreement;

         3.4.4    the Existing Performance Bonds; and

         3.4.5    any other bonding facility expressly permitted pursuant to
                  Section 4.07 (Limitations on Indebtedness and Preferred Stock)
                  of the Senior Note Indenture and Section 4.06 (Limitations on
                  Indebtedness and Preferred Stock) of the Junior Note
                  Indenture,

         in each case as a result of the provision of cash collateral as
         permitted pursuant to the terms of the Indentures or any of them, the
         Escrow Agreement or the Security Trust and Intercreditor Deed.

4.       CRYSTALLISATION OF FLOATING CHARGE

4.1      CRYSTALLISATION: BY NOTICE

         By notice in writing to Marconi Corporation and the Company, the
         Security Trustee may and shall, if so instructed pursuant to the
         Security Trust and Intercreditor Deed, convert the floating charge
         created by Clause 3.3 (Floating Charge) with immediate effect into a
         fixed charge as regards any property or assets specified in the notice
         if:

         4.1.1    an Event of Default has occurred and is continuing; or

         4.1.2    any person attempts to levy any distress, execution, diligence
                  or other similar process against or to appoint a Receiver over
                  any of the Charged Property; or

         4.1.3    the Security Trustee considers that any of the Charged
                  Property may be in jeopardy or in danger of being seized or
                  sold pursuant to any form of legal

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                  process, other than a voluntary sale of Charged Property
                  entered into by the Company and permitted by the Indentures
                  PROVIDED THAT the Security Trustee shall not be under any duty
                  to monitor the Charged Property.

4.2      CRYSTALLISATION: AUTOMATIC

         Notwithstanding Clause 4.1 (Crystallisation: By Notice) and without
         prejudice to any law which may have a similar effect, the floating
         charge will automatically be converted (without notice) with immediate
         effect into a fixed charge as regards all the assets subject to the
         floating charge if:

         4.2.1    any person levies any distress, execution, diligence or other
                  similar process against, or appoints a Receiver over, any of
                  the Charged Property; or

         4.2.2    a resolution is passed or an order is made for the winding-up,
                  dissolution or re-organisation of the Company other than in
                  connection with a solvent reconstruction of the Company
                  permitted under the Indentures.

4.3      DE-CRYSTALLISATION:

         4.3.1    Where an asset has become subject to a fixed charge under
                  Clause 4.1 (Crystallisation: By Notice) or Clause 4.2
                  (Crystallisation: Automatic) the Security Trustee shall, if so
                  requested by the Company and if instructed to do so in
                  accordance with the Security Trust and Intercreditor Deed,
                  release the asset from that fixed charge by notice in writing
                  to Marconi Corporation and the Company.

         4.3.2    When an asset is released from the fixed charge under
                  sub-clause 4.3.1 above, the asset will again be subject to:

                  (a)      the floating charge under Clause 3.3 (Floating
                           Charge); and

                  (b)      the further operation of Clause 4.1 (Crystallisation:
                           By Notice) or Clause 4.2 (Crystallisation:
                           Automatic).

5.       PERFECTION OF SECURITY

5.1      NOTICES OF ASSIGNMENT

         Pursuant to Clause 20 (Power of Attorney), the Security Trustee may,
         upon the occurrence of an Insolvency Event of Default and shall, if so
         instructed pursuant to the Security Trust and Intercreditor Deed upon
         or at any time after the occurrence of any Event of Default which is
         continuing, deliver to relevant persons Notices of Assignment duly
         executed by the Security Trustee on behalf of the Company in respect of
         the Intra-Group Loan Contracts.

5.2      NOTICES OF CHARGE

         5.2.1    If so required by the Security Trustee from time to time,
                  within 10 Business Days after the Company enters into any
                  lease falling within the ambit of the security created
                  pursuant to Clause 3 (Fixed Charges, Assignments and Floating
                  Charge), the Company will join the Security Trustee in giving
                  a Notice of Charge to all such landlords and other persons
                  which are parties under such lease of the security constituted
                  under this Debenture in respect of such lease

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                  and will use all commercially reasonable endeavours to procure
                  from each of such landlords and persons an acknowledgement in
                  the form attached thereto.

         5.2.2    The Company shall within 10 Business Days after the date of
                  this Debenture, provide the Security Trustee with details of
                  all Accounts and Monetary Claims falling within the ambit of
                  the security created pursuant to Clause 3 (Fixed Charges,
                  Assignments and Floating Charge) deriving from or relating to
                  any Intellectual Property and in relation to all other
                  Accounts and Monetary Claims falling within the ambit of the
                  security created pursuant to Clause 3 (Fixed Charges,
                  Assignments and Floating Charge), immediately upon the
                  occurrence of an Insolvency Event of Default or upon request
                  by the Security Trustee if instructed pursuant to the Security
                  Trust and Intercreditor Deed upon or after the occurrence of
                  any Event of Default which is continuing, to enable the
                  Security Trustee to deliver a Notice of Charge in accordance
                  with sub-clause 5.2.3 and/or sub-clause 5.2.4 below.

         5.2.3    Pursuant to Clause 20 (Power of Attorney), the Security
                  Trustee may, upon the occurrence of an Insolvency Event of
                  Default and shall, if so instructed pursuant to the Security
                  Trust and Intercreditor Deed upon or at any time after the
                  occurrence of any Event of Default which is continuing,
                  deliver to relevant persons, Notices of Charge duly executed
                  by the Security Trustee on behalf of the Company in respect of
                  any Monetary Claims falling within the ambit of the security
                  created pursuant to Clause 3 (Fixed Charges, Assignments and
                  Floating Charge).

         5.2.4    Pursuant to Clause 20 (Power of Attorney), the Security
                  Trustee may, upon the occurrence of an Insolvency Event of
                  Default and shall, if so instructed pursuant to the Security
                  Trust and Intercreditor Deed upon or at any time after the
                  occurrence of any Event of Default which is continuing,
                  deliver to relevant persons Notices of Charge duly executed by
                  the Security Trustee on behalf of the Company in respect of
                  any Accounts falling within the ambit of the security created
                  pursuant to Clause 3 (Fixed Charges, Assignments and Floating
                  Charge).

5.3      REAL PROPERTY: DELIVERY OF DOCUMENTS OF TITLE

         The Company shall, upon the acquisition by it of any interest in any
         Real Property to the extent requested by the Security Trustee, deliver
         (or procure delivery) to or to the order of the Security Trustee of,
         and the Security Trustee shall be entitled to hold and retain, all
         deeds, certificates and other documents of title relating to such
         property.

5.4      FURTHER ADVANCES

         Subject to the terms of the Relevant Documents certain Secured
         Creditors are under an obligation to make further advances to the
         Company and that obligation will be deemed to be incorporated into this
         Debenture as if set out in this Debenture.

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5.5      DELIVERY OF SHARE CERTIFICATES

         The Company shall:

         5.5.1    within 10 Business Days of the date of this Debenture, deposit
                  (or procure the deposit of) with or to the order of the
                  Security Trustee or with such Delegate as the Security Trustee
                  may appoint for this purpose all certificates or other
                  documents of title to the Shares, and stock transfer forms or
                  other instruments of transfer in respect thereof (executed in
                  blank by or on behalf of the Company); and

         5.5.2    promptly upon the accrual, offer or issue of any stocks,
                  shares, warrants or other securities in respect of or derived
                  from the Shares, notify the Security Trustee of that
                  occurrence and procure the delivery to the Security Trustee or
                  to the order of the Security Trustee of (a) all certificates
                  or other documents of title representing such items and (b)
                  such stock transfer forms or other instruments of transfer
                  (executed in blank by or on behalf of the Company) in respect
                  thereof.

6.       FURTHER ASSURANCE

6.1      FURTHER ASSURANCE: GENERAL

         The Company shall promptly do all such acts or execute all such
         documents (including assignments, transfers, mortgages, charges,
         notices and instructions) as the Security Trustee may specify (and in
         such form as the Security Trustee may require in favour of the Security
         Trustee or its nominee(s)):

         6.1.1    to perfect the Security created or intended to be created in
                  respect of the Charged Property (which may include the
                  execution by the Company of a mortgage, charge or assignment
                  over all or any of the assets constituting, or intended to
                  constitute, Charged Property) or for the exercise of the
                  Collateral Rights;

         6.1.2    to confer on the Security Trustee Security over any property
                  and assets of the Company located in any jurisdiction outside
                  Hong Kong equivalent or similar to the Security intended to be
                  conferred by or pursuant to this Debenture;

         6.1.3    to confer on the Security Trustee Security and to create,
                  perfect, protect or maintain Security (which in so far as it
                  relates to Real Property (other than fittings, plant and
                  machinery) in Hong Kong shall be a legal charge) over all its
                  right, title and interest from time to time in any Real
                  Property including using commercially reasonable efforts to
                  ensure that any such Real Property which is or is to be the
                  subject of any contract, instrument or agreement which comes
                  into being on or after the date of this Debenture shall be
                  capable of being the subject of such security in favour of the
                  Security Trustee; and/or

         6.1.4    to facilitate the realisation of the Charged Property.

6.2      NECESSARY ACTION

         If so requested by the Security Trustee the Company shall take all such
         action as is available to it (including making all filings and
         registrations) as may be necessary for the

                                     - 10 -

<PAGE>

         purpose of the creation, perfection, protection or maintenance of any
         Security conferred or intended to be conferred on the Security Trustee
         by or pursuant to this Debenture.

7.       NEGATIVE PLEDGE AND DISPOSALS

7.1      NEGATIVE PLEDGE

         The Company undertakes that it shall not, at any time during the
         subsistence of this Debenture, create or permit to subsist any Security
         over all or any part of the Charged Property except as not expressly
         prohibited under the terms of the Indentures.

7.2      NO DISPOSAL OF INTERESTS

         The Company undertakes that it shall not (and shall not agree to) at
         any time during the subsistence of this Debenture, except as not
         expressly prohibited under the terms of the Indentures:

         7.2.1    execute any conveyance, disposition, transfer, lease,
                  assignment or assignation of, or other right to use or occupy,
                  all or any part of the Charged Property;

         7.2.2    create any legal or equitable estate or heritable interest or
                  other interest in, or over, or otherwise relating to, all or
                  any part of the Charged Property; or

         7.2.3    (a) grant or vary, or accept any surrender, or cancellation or
                  renunciation or disposal of, any lease, tenancy, licence,
                  consent or other right to use or occupy in relation to any of
                  the Charged Property or (b) allow any person any right to use
                  or occupy or to become entitled to assert any proprietary
                  interest in, or right over, the Charged Property, which may,
                  in each case, adversely affect the ability of the Security
                  Trustee to exercise any of the Collateral Rights.

8.       SHARES

8.1      SHARES: BEFORE ENFORCEMENT EVENT

         Prior to the occurrence of an Enforcement Event and at any time when no
         Enforcement Event is continuing, the Company shall:

         8.1.1    be entitled to retain all dividends, interest and other monies
                  arising from the Shares; and

         8.1.2    exercise all voting rights in relation to the Shares PROVIDED
                  THAT the Company shall not exercise such voting rights in any
                  manner which would constitute a Default or an Event of Default
                  under the Indentures (as such terms are defined in the
                  Indentures).

8.2      SHARES: AFTER ENFORCEMENT EVENT

         The Security Trustee may, upon the occurrence of an Enforcement Event
         and at any time thereafter whilst such Enforcement Event is continuing
         (in the name of the Company or otherwise and without any further
         consent or authority from the Company):

         8.2.1    exercise (or refrain from exercising) any voting rights in
                  respect of any of the Shares;

                                     - 11 -

<PAGE>

         8.2.2    apply all dividends, interest and other monies arising from
                  any of the Shares in accordance with Clause 18 (Application of
                  Moneys);

         8.2.3    transfer any of the Shares into the name of such nominee(s) of
                  the Security Trustee as it shall require; and

         8.2.4    exercise (or refrain from exercising) the powers and rights
                  conferred on or exercisable by the legal or beneficial owner
                  of any of the Shares, including the right, in relation to any
                  company whose shares or other securities are included in the
                  Charged Property, to concur or participate in:

                  (a)      the reconstruction, amalgamation, sale or other
                           disposal of such company or any of its assets or
                           undertaking (including the exchange, conversion or
                           reissue of any shares or securities as a consequence
                           thereof),

                  (b)      the release, modification or variation of any rights
                           or liabilities attaching to such shares or
                           securities, and

                  (c)      the exercise, renunciation or assignment of any right
                           to subscribe for any shares or securities,

                  in each case in such manner and on such terms as the Security
                  Trustee may think fit, and the proceeds of any such action
                  shall form part of the Charged Property.

9.       ACCOUNTS

9.1      ACCOUNTS: OPERATION BEFORE ENFORCEMENT EVENT

         The Company shall, prior to the delivery of a Notice of Charge pursuant
         to Clause 5.2 (Notices of Charge) or the occurrence of an Enforcement
         Event and at any time thereafter when no Enforcement Event is
         continuing (provided that at such time no Notice of Charge has been
         delivered pursuant to Clause 5.2 (Notices of Charge), be entitled to
         receive, withdraw or otherwise transfer any credit balance from time to
         time on any Account.

9.2      ACCOUNTS: OPERATION AFTER ENFORCEMENT EVENT

         After the delivery of a Notice of Charge pursuant to Clause 5.2
         (Notices of Charge) or the occurrence of an Enforcement Event and at
         any time thereafter while such Enforcement Event is continuing, the
         Company shall not be entitled to receive, withdraw or otherwise
         transfer any credit balance from time to time on any Account except
         with the prior consent of the Security Trustee.

9.3      ACCOUNTS: APPLICATION OF MONIES

         The Security Trustee shall, upon the occurrence of an Enforcement Event
         and at any time thereafter whilst such Enforcement Event is continuing,
         be entitled without notice to apply, transfer or set-off any or all of
         the credit balances from time to time on any Account in or towards the
         payment or other satisfaction of all or part of the Secured Obligations
         in accordance with Clause 18 (Application of Moneys).

                                     - 12 -

<PAGE>

10.      MONETARY CLAIMS

10.1     DEALING WITH MONETARY CLAIMS

         The Company shall not at any time during the subsistence of the
         Debenture, without the prior written consent of the Security Trustee or
         except as not expressly prohibited under the terms of the Indentures:

         10.1.1   deal with the Monetary Claims referred to in sub-clause 3.1.5
                  of Clause 3.1 (Fixed Charges) except by getting in and
                  realising them in a prudent manner (on behalf of the Security
                  Trustee) and paying the proceeds of those Monetary Claims
                  referred to in sub-clause 3.1.5 of Clause 3.1 (Fixed Charges)
                  into the Accounts or as the Security Trustee may require (and
                  such proceeds shall be held upon trust by the Company for the
                  Security Trustee on behalf of the Secured Creditors prior to
                  such payment in);

         10.1.2   factor or discount any of the Monetary Claims referred to in
                  sub-clause 3.1.5 of Clause 3.1 (Fixed Charges) or enter into
                  any agreement for such factoring or discounting; or

         10.1.3   (other than as provided in Clause 10.2 (Release of Monetary
                  Claims: Before Enforcement Event) be entitled to withdraw or
                  otherwise transfer the proceeds of the realisation of any
                  Monetary Claims standing to the credit of any Account.

10.2     RELEASE OF MONETARY CLAIMS: BEFORE ENFORCEMENT EVENT

         Prior to the delivery of a Notice of Charge pursuant to Clause 5.2
         (Notices of Charge) or the occurrence of an Enforcement Event and at
         any time when no Enforcement Event is continuing (provided that at such
         time no Notice of Charge has been delivered pursuant to Clause 5.2
         (Notices of Charge)), the proceeds of the realisation of any Monetary
         Claims deriving from or in relation to any Intellectual Property shall
         (subject to any restriction on the application of such proceeds
         contained in this Debenture, the Indentures or in the Security Trust
         and Intercreditor Deed), upon such proceeds being credited to an
         Account, be released from the fixed charge created pursuant to Clause
         3.1 (Fixed Charges) and the Company shall be entitled to withdraw such
         proceeds from such Account provided that such proceeds shall continue
         to be subject to the floating charge created pursuant to Clause 3.3
         (Floating Charge) and the terms of this Debenture.

11.      REAL PROPERTY

11.1     PROPERTY: NOTIFICATION

         The Company shall promptly notify the Security Trustee of any contract,
         conveyance, transfer or other disposition for the acquisition by the
         Company (or its nominee(s)) of any Real Property and shall promptly
         enter into a further document or deed in respect of such Real Property
         if so required by the Security Trustee.

11.2     ENTITLEMENT TO REMEDY

         If the Company fails to comply with any of the undertakings contained
         in this Clause 11, the Security Trustee shall be entitled (with such
         agents, contractors and others as it sees fit) to do such things as may
         in the opinion of the Security Trustee be required to remedy such
         failure and all moneys spent by the Security Trustee in doing so shall
         be reimbursed

                                     - 13 -

<PAGE>

         by the Company on demand with interest from the date of payment by the
         Security Trustee until reimbursed in accordance with Clause 2.2
         (Interest on Demands).

12.      INVESTMENTS: DELIVERY OF DOCUMENTS OF TITLE

         After the occurrence of an Enforcement Event, the Company shall
         promptly deliver (or procure delivery) to the Security Trustee, and the
         Security Trustee shall be entitled to retain, all of the Investments
         and any certificates and other documents of title representing the
         Investments to which the Company (or its nominee(s)) is or becomes
         entitled together with any other document which the Security Trustee
         may request (in such form and executed as the Security Trustee may
         require) with a view to perfecting or improving its security over the
         Investments or to registering any Investment in its name or the name of
         any nominee(s).

13.      INTRA-GROUP LOAN CONTRACTS

         Prior to the delivery of a Notice of Assignment pursuant to Clause 5.1
         (Notices of Assignment) or the occurrence of an Enforcement Event, the
         Company shall be entitled to deal with the Intra-Group Loan Contracts
         except as expressly prohibited under the Indentures or the Security
         Trust and Intercreditor Deed.

14.      ENFORCEMENT OF SECURITY

14.1     ENFORCEMENT

         At any time after the occurrence of an Enforcement Event and the
         Security Trustee (acting on the instructions received pursuant to the
         terms of the Security Trust and Intercreditor Deed) giving notice to
         Marconi Corporation and the Company thereof, the security created by or
         pursuant to this Debenture is immediately enforceable and the Security
         Trustee may, in its absolute discretion:

         14.1.1   enforce all or any part of that security (at the times, in the
                  manner and on the terms it thinks fit) and take possession of
                  and hold or dispose of all or any part of the Charged
                  Property; and

         14.1.2   whether or not it has appointed a Receiver, exercise all or
                  any of the powers, authorities and discretions conferred by
                  the Conveyancing and Property Ordinance (Cap.219) (as varied
                  or extended by this Debenture) insofar as applicable on
                  mortgagees and by this Debenture on any Receiver or otherwise
                  conferred by law on mortgagees or Receivers.

14.2     NO LIABILITY AS MORTGAGEE IN POSSESSION

         Neither the Security Trustee nor any Receiver shall be liable to
         account as a mortgagee or heritable creditor in possession in respect
         of all or any part of the Charged Property or be liable for any loss
         upon realisation or for any neglect, default or omission in connection
         with the Charged Property to which a mortgagee in possession or
         heritable creditor might otherwise be liable.

                                     - 14 -

<PAGE>

15.      EXTENSION AND VARIATION OF CONVEYANCING AND PROPERTY ORDINANCE

15.1     EXTENSION OF POWERS

         Insofar as applicable the power of sale or other disposal conferred on
         the Security Trustee and on any Receiver by this Debenture shall
         operate as a variation and extension of the statutory power of sale
         under Sections 51 and 53 of the Conveyancing and Property Ordinance
         (Cap.219) and such power shall arise (and the Secured Obligations shall
         be deemed due and payable for that purpose) on execution of this
         Debenture.

15.2     RESTRICTIONS

         The restrictions contained in paragraph 11 of the Fourth Schedule to
         the Conveyancing and Property Ordinance (Cap.219) shall not apply to
         this Debenture or to the exercise by the Security Trustee of its right
         to consolidate all or any of the security created by or pursuant to
         this Debenture with any other security in existence at any time or to
         its power of sale, which powers may be exercised by the Security
         Trustee without notice to the Company on or at any time after the
         occurrence of an Enforcement Event.

15.3     POWER OF LEASING

         The statutory powers of leasing, surrendering leases and accepting
         surrenders of leases conferred by the Fourth Schedule to the
         Conveyancing and Property Ordinance (Cap.219) may be exercised by the
         Security Trustee at any time on or after the occurrence of an
         Enforcement Event and, without prejudice to the foregoing, the Security
         Trustee and any Receiver may, whether or not the Security Trustee and
         such Receiver shall then be in possession of the relevant property,
         make any lease or agreement for lease, accept surrenders of leases and
         grant options on such terms (including without limitation as to premium
         and length of term) as it or he shall think fit, without the need to
         comply with any requirement or restriction imposed by the Fourth
         Schedule to the Conveyancing and Property Ordinance (Cap.219).

16.      APPOINTMENT OF RECEIVER

16.1     APPOINTMENT AND REMOVAL

         After the occurrence of an Enforcement Event or if requested to do so
         by the Company, the Security Trustee may by deed or otherwise (acting
         through an authorised officer of the Security Trustee), without prior
         notice to the Company:

         16.1.1   appoint one or more persons to be a Receiver of the whole or
                  any part of the Charged Property;

         16.1.2   remove (so far as it is lawfully able) any Receiver so
                  appointed; and

         16.1.3   appoint another person(s) as an additional or replacement
                  Receiver(s).

16.2     CAPACITY OF RECEIVERS

         Each person appointed to be a Receiver pursuant to Clause 16.1
         (Appointment and Removal) shall be:

         16.2.1   entitled to act individually or together with any other person
                  appointed or substituted as Receiver;

                                     - 15 -

<PAGE>

         16.2.2   for all purposes shall be deemed to be the agent of the
                  Company, who shall be solely responsible for his acts,
                  defaults and liabilities and for the payment of his
                  remuneration and no Receiver shall at any time act as agent
                  for the Security Trustee; and

         16.2.3   entitled to remuneration for his services at a rate to be
                  fixed by the Security Trustee from time to time.

16.3     STATUTORY POWERS OF APPOINTMENT

         The powers of appointment of a Receiver shall be in addition to all
         statutory and other powers of appointment of the Security Trustee under
         the Conveyancing and Property Ordinance (Cap.219) (as extended by this
         Debenture) or otherwise and such powers shall remain exercisable from
         time to time by the Security Trustee in respect of any part of the
         Charged Property.

17.      POWERS OF RECEIVER

17.1     POWERS OF RECEIVER

         Every Receiver shall (subject to any restrictions in the instrument
         appointing him but notwithstanding any winding-up or dissolution of the
         Company) have and be entitled to exercise, in relation to the Charged
         Property (and any assets of the Company which, when got in, would be
         Charged Property) in respect of which he was appointed, and as varied
         and extended by the provisions of this Debenture (in the name of or on
         behalf of the Company or in his own name and, in each case, at the cost
         of the Company):

         17.1.1   insofar as applicable all the powers conferred by the
                  Conveyancing and Property Ordinance (Cap.219) on mortgagors
                  and on mortgagees in possession and on receivers appointed
                  under that Ordinance;

         17.1.2   all the powers and rights of an absolute owner and power to do
                  or omit to do anything which the Company itself could do or
                  omit to do; and

         17.1.3   the power to do all things (including bringing or defending
                  proceedings in the name or on behalf of the Company) which
                  seem to the Receiver to be incidental or conducive to (a) any
                  of the functions, powers, authorities or discretions conferred
                  on or vested in him or (b) the exercise of the Collateral
                  Rights (including realisation of all or any part of the
                  Charged Property) or (c) bringing to his hands any assets of
                  the Company forming part of, or which when got in would be,
                  Charged Property.

17.2     ADDITIONAL POWERS OF RECEIVER

         In addition to and without prejudice to the generality of the
         foregoing, every Receiver shall (subject to any limitations or
         restrictions expressed in the instrument appointing him but
         notwithstanding any winding-up or dissolution of the Company) have the
         powers set out in Schedule 3 (Additional Powers of Receiver) in
         relation to the Charged Property (and any assets of the Company which,
         when got in, would be part of the Charged Property), in respect of
         which he was appointed (and every reference in Schedule 3 (Additional
         Powers of Receiver) to the "Charged Property" shall be read as a
         reference to that part of the Charged Property in respect of which such
         Receiver was appointed).

                                     - 16 -

<PAGE>

17.3     MANNER OF EXERCISING POWERS

         In making any sale or other disposal of all or any part of the Charged
         Property or any acquisition in the exercise of their respective powers
         (including without limitation a disposal by a Receiver to any
         subsidiary of the Company or other body corporate) any Receiver or the
         Security Trustee may accept or dispose of as, and by way of
         consideration for, such sale or other disposal or acquisition, cash,
         shares, loan capital or other obligations, including without limitation
         consideration fluctuating according to or dependent upon profit or
         turnover and consideration the amount whereof is to be determined by a
         third party. Any such consideration may, if thought expedient by such
         Receiver or the Security Trustee, be nil or may be payable or
         receivable in a lump sum or by instalments. Any contract for any such
         sale, disposal or acquisition by such Receiver or the Security Trustee
         may contain conditions excluding or restricting the personal liability
         of such Receiver or the Security Trustee.

18.      APPLICATION OF MONEYS

         All moneys received or recovered by the Security Trustee or any
         Receiver pursuant to this Debenture or the powers conferred by it shall
         (subject to the claims of any person having prior rights thereto and by
         way of variation of the provisions of the Conveyancing and Property
         Ordinance (Cap.219)) be applied first in the payment of the costs,
         charges and expenses incurred and payments made by the Receiver, the
         payment of his remuneration and the discharge of any liabilities
         incurred by the Receiver in, or incidental to, the exercise of any of
         his powers, and thereafter shall be applied by the Security Trustee
         (notwithstanding any purported appropriation by the Company) in
         accordance with the Security Trust and Intercreditor Deed.

19.      PROTECTION OF PURCHASERS

19.1     CONSIDERATION

         The receipt of the Security Trustee or any Receiver shall be conclusive
         discharge to a purchaser and, in making any sale or disposal of any of
         the Charged Property or making any acquisition, the Security Trustee or
         any Receiver may do so for such consideration, in such manner and on
         such terms as it thinks fit.

19.2     PROTECTION OF PURCHASERS

         No purchaser or other person dealing with the Security Trustee or any
         Receiver shall be bound to inquire whether the right of the Security
         Trustee or such Receiver to exercise any of its powers has arisen or
         become exercisable or be concerned with any propriety or regularity on
         the part of the Security Trustee or such Receiver in such dealings.

20.      POWER OF ATTORNEY

20.1     APPOINTMENT AND POWERS

         The Company by way of security irrevocably (within the meaning of
         Section 4 of the Powers of Attorney Ordinance (Cap.31)) appoints the
         Security Trustee, each Delegate and any Receiver severally to be its
         attorney (the "Attorney") and in its name, on its behalf and as its act
         and deed to execute, deliver and perfect all documents and do all
         things which the Attorney may consider to be required or desirable for:

                                     - 17 -

<PAGE>

         20.1.1   carrying out any obligation imposed on the Company by this
                  Debenture (including the execution and delivery of any
                  notices, deeds, charges, assignments or other security and any
                  transfers of the Charged Property); and

         20.1.2   enabling the Security Trustee, each Delegate and any Receiver
                  to exercise, or delegate the exercise of, any of the rights,
                  powers and authorities conferred on them by or pursuant to
                  this Debenture or by law (including, after the occurrence of
                  an Enforcement Event, the exercise of any right of a legal or
                  beneficial owner of the Charged Property).

20.2     RATIFICATION

         The Company shall ratify and confirm all things done and all documents
         executed by any Attorney in the exercise or purported exercise of all
         or any of his powers.

20.3     INDEMNITY

         The Company shall indemnify the Attorney and keep the Attorney
         indemnified against any and all costs, claims and liabilities which the
         Attorney may incur as a result of anything done by the Attorney in the
         proper exercise of any of the powers conferred, or purported to be
         conferred, on him or her by this Debenture unless such cost, claim or
         liability arises as a result of the negligence or wilful misconduct of
         the Attorney.

21.      EFFECTIVENESS OF SECURITY

21.1     CONTINUING SECURITY

         The security created by or pursuant to this Debenture shall remain in
         full force and effect as a continuing security for the Secured
         Obligations unless and until discharged by the Security Trustee.

21.2     CUMULATIVE RIGHTS

         The security created by or pursuant to this Debenture and the
         Collateral Rights shall be cumulative, in addition to and independent
         of every other security which the Security Trustee or any Secured
         Creditor may at any time hold for the Secured Obligations or any other
         obligations or any rights, powers and remedies provided by law. No
         prior security held by the Security Trustee (whether in its capacity as
         trustee or otherwise) or any of the other Secured Creditors over the
         whole or any part of the Charged Property shall merge into the security
         constituted by this Debenture.

21.3     NO PREJUDICE

         The security created by or pursuant to this Debenture and the
         Collateral Rights shall not be prejudiced by any unenforceability or
         invalidity of any other agreement or document or by any time or
         indulgence granted to the Company or any other person, or the Security
         Trustee (whether in its capacity as trustee or otherwise) or any of the
         other Secured Creditors or by any variation of the terms of the trust
         upon which the Security Trustee holds the security or by any other
         thing which might otherwise prejudice that security or any Collateral
         Right.

21.4     REMEDIES AND WAIVERS

         No failure on the part of the Security Trustee to exercise, or any
         delay on its part in exercising, any Collateral Right shall operate as
         a waiver thereof, nor shall any single or

                                     - 18 -

<PAGE>

         partial exercise of any Collateral Right preclude any further or other
         exercise of that or any other Collateral Right.

21.5     NO LIABILITY

         None of the Security Trustee, each Delegate, any Attorney or any
         Receiver shall be liable by reason of (a) taking any action permitted
         by this Debenture or (b) any neglect or default in connection with the
         Charged Property or (c) taking possession of or realising all or any
         part of the Charged Property, except in the case of negligence or
         wilful misconduct upon its part.

21.6     PARTIAL INVALIDITY

         If, at any time, any provision of this Debenture is or becomes illegal,
         invalid or unenforceable in any respect under the law of any
         jurisdiction, neither the legality, validity or enforceability of the
         remaining provisions of this Debenture nor of such provision under the
         laws of any other jurisdiction shall in any way be affected or impaired
         thereby and, if any part of the security intended to be created by or
         pursuant to this Debenture is invalid, unenforceable or ineffective for
         any reason, that shall not affect or impair any other part of the
         security.

21.7     COMPANY'S OBLIGATIONS

         The obligations of the Company and the Collateral Rights shall not be
         discharged, impaired or otherwise affected by:

         21.7.1   any winding-up, dissolution, administration or re-organisation
                  of or other change in any Obligor or any other person;

         21.7.2   any of the Secured Obligations being at any time illegal,
                  invalid, unenforceable or ineffective;

         21.7.3   any time or other indulgence being granted to any Obligor or
                  any other person;

         21.7.4   any amendment, variation, waiver or release of any of the
                  Secured Obligations;

         21.7.5   any failure to take or failure to realise the value of any
                  other collateral in respect of the Secured Obligations or any
                  release, discharge, exchange or substitution of any such
                  collateral;

         21.7.6   any other act, event or omission which but for this provision
                  would or might operate to impair, discharge or otherwise
                  affect the obligations of the Company hereunder.

22.      RELEASE OF SECURITY

         The Security Trustee shall, at the cost of the Company, release and
         cancel the security constituted by this Debenture and procure the
         reassignment to the Company of the property and assets assigned to the
         Security Trustee pursuant to this Debenture in accordance with the
         terms and subject to the conditions and circumstances set out in the
         Security Trust and Intercreditor Deed and without recourse to, or any
         representation or warranty by, the Security Trustee or any of its
         nominees.

                                     - 19 -

<PAGE>

23.      SET-OFF

         The Company authorises the Security Trustee (but the Security Trustee
         shall not be obliged to exercise such right), after the occurrence of
         an Enforcement Event which is continuing, to set off against the
         Secured Obligations any amount or other obligation (contingent or
         otherwise) owing by the Security Trustee to the Company.

24.      SUBSEQUENT SECURITY INTERESTS

         If the Security Trustee (acting in its capacity as trustee or
         otherwise) or any of the other Secured Creditors at any time receives
         or is deemed to have received notice of any subsequent Security
         affecting all or any part of the Charged Property or any assignment or
         transfer of the Charged Property which is prohibited by the terms of
         this Debenture or the Indentures, all payments thereafter by or on
         behalf of the Company to (or on behalf of) the Security Trustee
         (whether in its capacity as trustee or otherwise) or any of the other
         Secured Creditors shall be treated as having been credited to a new
         account of the Company and not as having been applied in reduction of
         the Secured Obligations as at the time when the Security Trustee
         received such notice.

25.      CURRENCY INDEMNITY

         If any sum (a "SUM") owing by the Company under this Debenture or any
         order or judgment given or made in relation to this Debenture has to be
         converted from the currency (the "FIRST CURRENCY") in which such Sum is
         payable into another currency (the "SECOND CURRENCY") for the purpose
         of:

         25.1.1   making or filing a claim or proof against the Company;

         25.1.2   obtaining an order or judgment in any court or other tribunal;

         25.1.3   enforcing any order or judgment given or made in relation to
                  this Debenture; or

         25.1.4   applying the Sum in satisfaction of any of the Secured
                  Obligations,

         the Company shall indemnify the Security Trustee from and against any
         loss suffered or incurred as a result of any discrepancy between (a)
         the rate of exchange used for such purpose to convert such Sum from the
         First Currency into the Second Currency and (b) the rate or rates of
         exchange available to the Security Trustee at the time of such receipt
         of such Sum.

26.      ASSIGNMENT

         The Security Trustee may assign and transfer all or any of its rights
         and obligations under this Debenture in accordance with the Security
         Trust and Intercreditor Deed. The Security Trustee shall be entitled to
         disclose such information concerning the Company and this Debenture as
         the Security Trustee considers appropriate to any actual or proposed
         direct or indirect successor or to any person to whom information may
         be required to be disclosed by any applicable law.

                                     - 20 -

<PAGE>

27.      NOTICES

         Each communication to be made under this Debenture shall be made and
         delivered in accordance with the provisions of the Security Trust and
         Intercreditor Deed.

28.      EXPENSES, COSTS AND TAXES

28.1     EXPENSES

         The Company shall, from time to time and promptly on demand by the
         Security Trustee, reimburse to the Security Trustee all costs and
         expenses (including legal fees) on a full indemnity basis together with
         any applicable value-added tax incurred by the Security Trustee and any
         Delegate (PROVIDED THAT in relation to sub-clause 28.1.1 of this Clause
         28.1, such costs and expenses must be properly incurred) in connection
         with:

         28.1.1   the execution, release and discharge of this Debenture and the
                  Security created or intended to be created in respect of the
                  Charged Property and the perfection of the Security
                  contemplated in this Debenture or in any such documents or
                  forming part of the Security created or intended to be created
                  in respect of the Charged Property;

         28.1.2   the actual or contemplated exercise, preservation and/or
                  enforcement of any of the rights, powers and remedies of, or
                  the performance of the duties and obligations of, the Security
                  Trustee or any Delegate, or any amendment or waiver in respect
                  of this Debenture;

         28.1.3   the foreclosure of any Charged Property; and

         28.1.4   the preservation and/or enforcement of the Security created or
                  intended to be created in respect of the Charged Property,

         which shall carry interest from the date of such demand until so
         reimbursed at the rate and on the basis as mentioned in Clause 2.2
         (Interest on Demands).

28.2     STAMP TAXES

         The Company shall pay promptly on demand of the Security Trustee all
         stamp, registration, notarial and other similar Taxes or fees paid or
         payable by the Security Trustee in connection with any action taken or
         contemplated by or on behalf of the Security Trustee for perfecting,
         enforcing, releasing, cancelling, reassigning or resolving any doubt
         concerning, or for any other purpose in relation to this Debenture, any
         amendment thereto, any transfer and/or assignment of the rights and/or
         obligations under the same or the Security created or intended to be
         created in respect of the Charged Property and shall, from time to
         time, indemnify the Security Trustee promptly on demand against any
         liabilities, costs, claims and expenses resulting from any failure to
         pay by the Company or any delay by the Company in paying any such Taxes
         or fees.

29.      PAYMENTS FREE OF DEDUCTION

         All payments to be made to the Security Trustee, any Delegate and/or
         any Receiver under this Debenture shall be made free and clear of and
         without set-off or deduction for or on account of tax unless the
         Company is required to make such payment subject to the deduction or
         withholding of tax, in which case the sum payable by the Company in

                                     - 21 -

<PAGE>

         respect of which such deduction or withholding is required to be made
         shall be increased to the extent necessary to ensure that, after the
         making of such deduction or withholding, the person on account of whose
         liability to tax such deduction or withholding has been made receives
         and retains (free from any liability in respect of any such deduction
         or withholding) a net sum equal to the sum which it would have received
         and so retained had no such deduction or withholding been made or
         required to be made.

30.      DISCRETION AND DELEGATION

30.1     DISCRETION

         Any liberty or power which may be exercised or any determination which
         may be made hereunder by the Security Trustee or any Receiver may,
         subject to the terms and conditions of this Debenture and the Security
         Trust and Intercreditor Deed, be exercised or made in its absolute and
         unfettered discretion without any obligation to give reasons.

30.2     DELEGATION

         Each of the Security Trustee and any Receiver shall have full power to
         delegate (either generally or specifically) the powers, authorities and
         discretions conferred on it by this Debenture (including the power of
         attorney) on such terms and conditions as it shall see fit which
         delegation shall not preclude either the subsequent exercise of such
         power, authority or discretion by the Security Trustee or the Receiver
         itself or any subsequent delegation or revocation thereof.

31.      PERPETUITY PERIOD

         The perpetuity period under the rule against perpetuities, if
         applicable to this Debenture, shall be the period of eighty years from
         the date of the Security Trust and Intercreditor Deed.

32.      GOVERNING LAW

         This Debenture and all matters arising from or connected with it are
         governed by the laws of Hong Kong.

33.      JURISDICTION

33.1     HONG KONG COURTS

         The courts of Hong Kong have exclusive jurisdiction to settle any
         disputes (a "DISPUTE") arising out of, or connected with this Debenture
         (including a dispute regarding the existence, validity or termination
         of this Debenture or the consequences of its nullity).

33.2     CONVENIENT FORUM

         The parties agree that the courts of Hong Kong are the most appropriate
         and convenient courts to settle Disputes between them and, accordingly,
         that they will not argue to the contrary.

33.3     EXCLUSIVE JURISDICTION

         This Clause 33 is for the benefit of the Security Trustee only. As a
         result and notwithstanding Clause 33.1 (Hong Kong Courts), it does not
         prevent the Security Trustee from taking proceedings relating to a
         Dispute in any other courts with

                                     - 22 -

<PAGE>

         jurisdiction. To the extent allowed by law the Security Trustee may
         take concurrent proceedings in any number of jurisdictions.

34.      COUNTERPARTS

         This Debenture may be executed in any number of counterparts, each of
         which shall be deemed an original and this has the same effect as if
         the signatures on the counterparts were on a single copy of this
         Debenture. Any party may enter into this Debenture by signing any such
         counterpart.

THIS DEBENTURE has been signed on behalf of the Security Trustee and executed as
a deed by the Company and is delivered by it on the date specified above.

                                     - 23 -

<PAGE>

                                   SCHEDULE 1

                FORM OF NOTICE OF ASSIGNMENT OF INTRA-GROUP LOAN

To:      [          ]

                                                              Date: [          ]

Dear Sirs,

DEBENTURE DATED [       ] BY MARCONI COMMUNICATIONS ASIA LIMITED (THE "COMPANY")
AND THE LAW DEBENTURE TRUST CORPORATION P.L.C. (THE "SECURITY TRUSTEE") (THE
"DEBENTURE")

We hereby give you notice, as attorney for and on behalf of the Company, that
the Company has, pursuant to the Debenture, assigned to us as Security Trustee
all their right, title and interest in and to [details of contract] (the
"CONTRACT") including all moneys which may be payable in respect of the
Contract.

With effect from your receipt of this notice:

1.       all payments by you to the Company under or arising from the Contract
         should be made to us or to our order as we may specify in writing from
         time to time [details of the account into which sums are to be paid may
         be included];

2.       all remedies provided for in the Contract or available at law or in
         equity are exercisable by us;

3.       all rights to compel performance of the Contract are exercisable by us
         although the Company shall remain liable to perform all the obligations
         assumed by it under the Contract;

4.       all rights, interests and benefits whatsoever accruing to or for the
         benefit of the Company arising from the Contract belong to us and no
         changes may be made to the terms of the Contract nor may the Contract
         be terminated without our consent; and

5.       you are authorised and instructed, without requiring further approval
         from the Company, to provide us with such information relating to the
         Contract as we may from time to time request and to send us copies of
         all notices issued by you under the Contract to us as well as to the
         Company.

These instructions may not be revoked, nor may the terms of the Contract be
amended, varied or waived without our prior written consent.

We confirm that pursuant to Clause 5.1 (Notices of Assignment) and Clause 20
(Power of Attorney) of the Debenture, we are empowered and authorised to deliver
this Notice of Assignment for and on behalf of the Company.

This letter is governed by Hong Kong law.

                                     - 24 -

<PAGE>

Please acknowledge receipt of this notice by signing the acknowledgement on the
enclosed copy letter and returning it to us at [   ] marked for the attention
of [   ].

Yours faithfully,

.......................

by THE LAW DEBENTURE TRUST CORPORATION p.l.c.

as attorney for and on behalf of

MARCONI COMMUNICATIONS ASIA LIMITED

                                     - 25 -

<PAGE>

[On copy only:

To:      [THE LAW DEBENTURE TRUST CORPORATION P.L.C.] AS SECURITY TRUSTEE

We acknowledge receipt of a notice in the terms set out above and confirm that
we have not received notice of any previous assignments or charges of or over
any of the rights, interests and benefits in and to the Contract and that we
will comply with the terms of that notice.

We further confirm that:

(a)      no amendment, waiver or release of any of such rights, interests and
         benefits shall be effective without your prior written consent;

(b)      no termination of such rights, interests or benefits shall be effective
         unless we have given you thirty days written notice of the proposed
         termination, specifying the action necessary to avoid such termination;
         and

(c)      no breach or default on the part of the Company of any of the terms of
         the Contract shall be deemed to have occurred unless we have given you
         notice of such breach specifying how to make good such breach.

For and on behalf of [      ]

By:      ........................

Dated:

                                     - 26 -

<PAGE>

                                   SCHEDULE 2

                                     PART A
                      FORM OF NOTICE OF CHARGE TO LANDLORDS

To:               [Landlord]

Date:             [       ]

Dear Sirs,

We give you notice that, by a Debenture dated [  ] (the "DEBENTURE") we charged
to The Law Debenture Trust Corporation p.l.c. (the "SECURITY TRUSTEE") as
security trustee for the Secured Creditors referred to in the Debenture all our
right, interests and benefits in, to and under the [describe Lease] dated [    ]
between [         ] relating to [          ] (including all monies payable
thereunder and the proceeds of all claims and judgments for breach of covenant)
(the "LEASE").

We will remain liable to perform all our obligations under the Lease and the
Security Trustee is under no obligation of any kind whatsoever under the Lease
nor under any liability whatsoever in the event of any failure by us to perform
our obligations under the Lease.

Please note that:

1.       all remedies provided for under the Lease or available at law or in
         equity are exercisable by the Security Trustee;

2.       all rights to compel performance of the Lease are exercisable by the
         Security Trustee; and

3.       all rights, interests and benefits whatsoever accruing to or for the
         benefit of ourselves arising under the Lease belong to the Security
         Trustee.

This letter is governed by and will be construed in accordance with the laws of
Hong Kong. Would you acknowledge receipt of this notice by sending the enclosed
acknowledgement to the Security Trustee with a copy to ourselves.

Yours faithfully

[               ]

MARCONI COMMUNICATIONS ASIA LIMITED

                                     - 27 -

<PAGE>

                            ACKNOWLEDGEMENT OF CHARGE

To:               The Law Debenture Trust Corporation p.l.c.
                  as Security Trustee

Date:             [       ]

Dear Sirs

We confirm receipt from Marconi Communications Asia Limited (the "COMPANY") of a
notice dated [   ] of a charge upon the terms of a Debenture dated [    ] (the
"DEBENTURE") to The Law Debenture Trust Corporation p.l.c. (the "SECURITY
TRUSTEE") as security trustee for the Secured Creditors of all the Company's
right, interest and benefit in, to and under the Lease (as specified in that
notice) to which we are a party.

We confirm that we have not received notice of any assignment or charge of or
over any of the rights, interests and benefits specified in such notice.

We further confirm that:

1.       no amendment, waiver or release of any such rights, interests and
         benefits will be effective without the prior written consent of the
         Security Trustee;

2.       no termination of such rights, interests or benefits will be effective
         unless we have given the Security Trustee at least 21 days' written
         notice of the proposed termination and specifying the action necessary
         to avoid such termination;

3.       the Company will remain liable to perform all its obligations under the
         Lease and the Security Trustee is under no obligation of any kind
         whatsoever under the Lease nor under any liability whatsoever in the
         event of any failure by the Company to perform our obligations under
         the Lease; and

4.       no breach or default on the part of the Company of any of the terms of
         such Lease will be deemed to have occurred unless we have given notice
         of such breach to the Security Trustee specifying how to make good such
         breach.

We unconditionally and irrevocably waive all rights of set-off, lien,
combination of accounts and similar rights (however described) which we may have
now or in the future to the extent that such rights relate to amounts owed to us
by the Company (and the proceeds thereof) and we will send you copies of all
statements, orders and notices given by us relating to such debt.

This letter is governed by and will be construed in accordance with the laws of
Hong Kong.

Yours faithfully

[Landlord]

                                     - 28 -

<PAGE>

                                     PART B
                      FORM OF NOTICE OF CHARGE OVER ACCOUNT

To: [Account Bank]

Dear Sirs,

We hereby give you notice, as attorney for and on behalf of Marconi
Communications Asia Limited (the "COMPANY"), that the Company has, pursuant to a
debenture dated [ ] (the "DEBENTURE"), charged to us as Security Trustee for and
on behalf of the Secured Creditors referred to therein, all their rights, title
and interest in and to all sums of money which may now or in the future be held
by the Company with you in any accounts at any of your branches (the
"ACCOUNTS"), together with all interest from time to time earned thereon and the
debts represented by such sums and interest, as well as all book and other debts
owed to the Company.

We hereby irrevocably authorise and instruct you:

(a)      to disclose to us without any reference to or further authority from
         the Company and without any enquiry by you as to the justification of
         such disclosure, such information relating to the Accounts and the sums
         therein as we may at any time and from time to time request;

(b)      to hold all sums from time to time standing to the credit of the
         Accounts to our order;

(c)      to pay or release all or any part of the sums from time to time
         standing to the credit of the Accounts in accordance with our written
         instructions at any time or times;

(d)      to comply with the terms of any written notice or instructions in any
         way relating to, or purporting to relate to, the Debenture, the sums
         standing to the credit of the Accounts from time to time or the debts
         represented thereby which you receive at any time from us without any
         reference to or further authority from the Company and without any
         enquiry by you as to the justification for or validity of such notice
         or instruction; and

(e)      to pay all monies received by you for the Accounts to (and only to) the
         credit of those Accounts.

Please note that the Company is not permitted to withdraw any amount from any of
the Accounts without our prior written consent.

Please also note that these instructions are not to be revoked or varied without
our prior written consent.

We confirm that pursuant to Clause 5.2 (Notices of Charge) and Clause 20 (Power
of Attorney) of the Debenture, we are empowered and authorised to deliver this
Notice of Charge for and on behalf of the Company.

This letter is governed by Hong Kong law.

                                     - 29 -

<PAGE>

Please acknowledge receipt of this notice by sending the attached
acknowledgement to us with a copy to the Company.

Yours faithfully,

.....................................
by The Law Debenture Trust Corporation p.l.c.
as attorney for and on behalf of Marconi Communications Asia Limited

                                     - 30 -

<PAGE>

                             FORM OF ACKNOWLEDGEMENT

To:      The Law Debenture Trust Corporation p.l.c.

Dear Sirs,

We confirm receipt from The Law Debenture Trust Corporation p.l.c. as attorney
for and on behalf of Marconi Communications Asia Limited (the "COMPANY") of a
notice dated [    ] relating to certain accounts (the "ACCOUNTS") of the Company
with the Bank.

We confirm that:

(i)      we accept the instructions and authorisations contained in that notice
         and we undertake to act in accordance with the terms of that notice;

(ii)     we have not received notice of the interest of any third party in the
         Accounts;

(iii)    we have neither claimed or exercised nor will claim or exercise any
         security interest, set-off, counter-claim or other rights in respect of
         the Accounts, the sums therein or the debts represented thereby without
         your prior written consent;

(iv)     we shall pay all monies received by us for the account of the Company
         to (and only to) the credit of the Account(s) in the name of the
         Company unless otherwise consented to by you; and

(v)      we shall not permit any amount to be withdrawn from any of the Accounts
         without your prior written consent.

Nothing contained in any of our arrangements with you shall commit us to
providing any facilities or making advances available to the Company.

This letter is governed by Hong Kong Law.

Yours faithfully,

................................
On behalf of [Bank]

                                     - 31 -

<PAGE>

                                     PART C
                  FORM OF NOTICE OF CHARGE OVER MONETARY CLAIMS

To:      [            ]

                                                              Date: [          ]

Dear Sirs,

DEBENTURE DATED [      ] BY MARCONI COMMUNICATIONS ASIA LIMITED (THE "COMPANY")
AND OTHERS AND THE LAW DEBENTURE TRUST CORPORATION P.L.C. (THE "SECURITY
TRUSTEE") (THE "DEBENTURE")

We hereby give you notice, as attorney for and on behalf of the Company, that
the Company has, pursuant to the Debenture, charged to us as Security Trustee
for and on behalf of the Secured Creditors referred to therein all their right,
title and interest in and to [details of Monetary Claim] (the "MONETARY CLAIM")
including all moneys which may be payable in respect of the Claim.

With effect from your receipt of this notice:

1.       all payments by you to the Company under or arising from the Monetary
         Claim should be made to us or to our order as we may specify in writing
         from time to time [details of the account into which sums are to be
         paid may be included];

2.       all remedies available at law or in equity in relation to the Monetary
         Claim are exercisable by us;

3.       all rights to compel performance of the underlying contract in respect
         of the Monetary Claim (the "UNDERLYING CONTRACT") between you and the
         Company are exercisable by us although the Company shall remain liable
         to perform all the obligations assumed by it thereunder;

4.       all rights, interests and benefits whatsoever accruing to or for the
         benefit of the Company arising from the Monetary Claim belong to us and
         no changes may be made to the terms of the Underlying Contract nor may
         the Underlying Contract be terminated without our consent; and

5.       you are authorised and instructed, without requiring further approval
         from the Company, to provide us with such information relating to the
         Monetary Claim as we may from time to time request and to send copies
         of all notices issued by you under the Underlying Contract to us as
         well as to the Company.

These instructions may not be revoked, nor amended, varied or waived without our
prior written consent.

                                     - 32 -

<PAGE>

We confirm that pursuant to Clause 5.2 (Notices of Charge) and Clause 20 (Power
of Attorney) of the Debenture, we are empowered and authorised to deliver this
Notice of Charge for and on behalf of the Company.

This letter is governed by Hong Kong law.

Please acknowledge receipt of this notice by signing the acknowledgement on the
enclosed copy letter and returning it to us at [    ] marked for the attention
of [    ].

Yours faithfully,

.......................

by THE LAW DEBENTURE TRUST CORPORATION P.L.C.
as attorney for and on behalf of
Marconi Communications Asia Limited

                                     - 33 -

<PAGE>

[On copy only:

To:      THE LAW DEBENTURE TRUST CORPORATION P.L.C. AS SECURITY TRUSTEE

We acknowledge receipt of a notice in the terms set out above and confirm that
we have not received notice of any previous charges of or over any of the
rights, interests and benefits in and to the Monetary Claim and that we will
comply with the terms of that notice.

We further confirm that:

(i)      no amendment, waiver or release of any of such rights, interests and
         benefits shall be effective without your prior written consent;

(ii)     no termination of such rights, interests or benefits shall be effective
         unless we have given you thirty days written notice of the proposed
         termination, specifying the action necessary to avoid such termination.

For and on behalf of [      ]

By:  ........................

Dated:

                                     - 34 -

<PAGE>

                                   SCHEDULE 3

                          ADDITIONAL POWERS OF RECEIVER

1.       Take Possession

         Power to enter upon, take immediate possession of, collect and get in
         the Charged Property including without limitation rents and other
         income whether accrued before or after the date of his appointment and
         for that purpose to make, or to require the directors of the Company to
         make, calls conditionally or unconditionally upon the holders of the
         Company's share capital in respect of any such capital of the Company
         which remains uncalled and to enforce payment of calls so made and any
         previous unpaid calls by taking proceedings in the name of the Company
         or in his own name.

2.       Proceedings and Claims

         Power to bring, prosecute, enforce, defend and abandon applications,
         claims, disputes, actions, suits and proceedings in connection with the
         business of the Company or all or any part of the Charged Property or
         this Debenture in the name of the Company or in his own name and to
         submit to arbitration, negotiate, compromise and settle any such
         applications, claims, disputes, actions, suits or proceedings and in
         addition to take or defend proceedings for the compulsory winding-up of
         the Company and proceedings for directions under Section 255 of the
         Companies Ordinance (Cap.32) of the laws of Hong Kong.

3.       Carry on Business

         Power to carry on and manage, or concur in the carrying on and
         management of or to appoint a manager of, the whole or any part of the
         Company's business in such manner as he shall in his absolute
         discretion think fit including without limitation the power to enter
         into any contract or arrangement and to perform, repudiate, rescind or
         vary any contract to which the Company is a party and power to
         supervise, control and finance any subsidiary of the Company or any
         other body corporate (including without limitation any referred to in
         Clause 6 below) and its business and the conduct thereof and to change
         the situation of the registered office of the Company or any such
         subsidiary or other body corporate.

4.       Deal with Charged Property

         Without the need to observe the restrictions imposed by paragraph 11 of
         the Fourth Schedule to the Conveyancing and Property Ordinance
         (Cap.219), power, in relation to the Charged Property and each and
         every part thereof, to sell, transfer, convey, grant or accept
         surrenders of leases, vary, terminate or surrender leases, grant, vary
         or terminate licences or rights of user (in each case with or without
         consideration) or concur in any of the foregoing by the Company or any
         other receiver or manager of the Company (including without limitation
         to or in relation to the Security Trustee or any of the other Secured
         Creditors) in such manner and generally on such terms as he thinks fit
         including without limitation, without the consent of the Company, the
         severing and separate

                                     - 35 -

<PAGE>

         disposal from the premises to which they were affixed of fixtures and
         plant and machinery.

5.       Acquisitions

         Power to purchase, lease, hire or otherwise acquire any assets or
         rights of any description which he shall in his absolute discretion
         consider necessary or desirable for the carrying on, improvement or
         realisation of the whole or any part of the Charged Property or the
         business of the Company or otherwise for the benefit of the whole or
         any part of the Charged Property.

6.       New Subsidiary

         Power to promote, procure the formation or otherwise acquire the share
         capital of, any body corporate with a view to such body corporate
         becoming a subsidiary of the Company or otherwise and purchasing,
         leasing or otherwise acquiring an interest in the whole or any part of
         the Charged Property or carrying on any business in succession to the
         Company or any subsidiary of the Company.

7.       Landlord and Tenant

         Power to make allowances to and re-arrangements with any lessees,
         tenants or other persons from whom any rents and profits may be
         receivable (including granting any licences and operating any rent
         reviews) and to exercise any powers and discretions conferred on a
         landlord or a tenant by any statutory provision or by general law from
         time to time in force in relation to all or any part of the Charged
         Property.

8.       Repairs etc

         Power to undertake, effect or complete any work of repair,
         refurbishment, decoration, modification, building, improvement or
         development of all or any part of the Charged Property as he may think
         expedient and to apply for and obtain any planning permissions,
         building regulation approvals and any other permissions, consents or
         licences in each case as he may in his absolute discretion think fit
         and to acquire (or acquire an interest in) any such property as he may
         think expedient.

9.       Insurance

         Power to effect, maintain or renew indemnity and other insurances and
         to obtain bonds and performance guarantees.

10.      Employment

         Power to employ, engage, dismiss or vary the terms of employment or
         engagement of such employees, workmen, servants, officers, managers,
         agents and advisers on such terms as to remuneration and otherwise as
         he shall think fit including without limitation power to engage his own
         firm in the conduct of the receivership.

                                     - 36 -

<PAGE>

11.      Borrowing

         Power to raise or borrow money from any of the Secured Creditors or any
         other person and with or without a mortgage or charge on the Charged
         Property or any part of it on such terms as he shall in his absolute
         discretion think fit (and no person lending such money shall be
         concerned to see or enquire as to the propriety or purpose of the
         exercise of such power or the application of money so raised or
         borrowed).

12.      Redemption of Security

         Power to redeem, discharge or compromise any security whether or not
         having priority to the security constituted by this Debenture or any
         part of it.

13.      Covenants, Guarantees and Indemnities

         Power to enter into bonds, covenants, guarantees, commitments,
         indemnities and other obligations or liabilities as he shall think fit,
         to make all payments needed to effect, maintain or satisfy such
         obligations or liabilities and to use the company seal of the Company.

14.      Exercise of Powers in Company's Name

         Power to exercise any or all of the above powers on behalf of and in
         the name of the Company (notwithstanding any winding-up or dissolution
         of the Company) or on his own behalf.

                                     - 37 -

<PAGE>

                                   SCHEDULE 4

                                DETAILS OF SHARES

<TABLE>
<CAPTION>
                                           Description and
                                           Number of Shares    Share Certificate
Name of Company    Issued Share Capital        Held                Number(s)
<S>                <C>                     <C>                 <C>
</TABLE>

__________________________________  NIL______________________________________

                                     - 38 -

<PAGE>

THE COMPANY

THE COMMON SEAL of                                   )
MARCONI COMMUNICATIONS ASIA LIMITED                  )                      SEAL
was hereunto affixed                                 )
in the presence of:                                  )

JOHN SHUM    Director

K F WONG     Director

Address:     29/F, 1063 KING'S ROAD, QUARRY BAY, HONG KNOG

Fax:         (852) 22507008

Attention:   JOHN SHUM

<PAGE>

THE SECURITY TRUSTEE

THE LAW DEBENTURE TRUST CORPORATION P.L.C.

By:               R D RANCE

Address:          THE LAW DEBENTURE TRUST CORPORATION P.L.C.

                  FIFTH FLOOR, 100 WOOD STREET, LONDON EC2V 7EX

Fax:

Attention:        MANAGER, TRUST ADMINISTRATION

Witnessed by:     KINNARI BHATT