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CLIFFORD CHANCE                                    LIMITED LIABILITY PARTNERSHIP

                                                                  CONFORMED COPY

                                                                     EXHIBIT 2.5

                                DATED 19 MAY 2003

                             MARCONI CORPORATION plc

                                   AND OTHERS

                                  AS COMPANIES

                                  IN FAVOUR OF

                    THE LAW DEBENTURE TRUST CORPORATION p.l.c

                               AS SECURITY TRUSTEE

                   ------------------------------------------

                               COMPOSITE DEBENTURE

                   ------------------------------------------

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                                    CONTENTS

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CLAUSE                                                                                    PAGE
<S>                                                                                       <C>
1.     Definitions And Interpretation..............................................         1
2.     Payment Of Secured Obligations..............................................         6
3.     Fixed Charges, Assignments And Floating Charge..............................         7
4.     Crystallisation Of Floating Charge..........................................         8
5.     Perfection Of Security......................................................         9
6.     Further Assurance...........................................................        12
7.     Negative Pledge And Disposals...............................................        13
8.     Shares......................................................................        14
9.     Accounts....................................................................        15
10.    Monetary Claims.............................................................        16
11.    Real Property...............................................................        17
12.    Intragroup Loan Contracts...................................................        17
13.    Investments: Delivery Of Documents Of Title.................................        17
14.    Enforcement Of Security.....................................................        17
15.    Extension And Variation Of The Law Of Property Act 1925.....................        18
16.    Appointment Of Receiver.....................................................        18
17.    Powers Of Receiver..........................................................        19
18.    Application Of Moneys.......................................................        20
19.    Protection Of Purchasers....................................................        20
20.    Power Of Attorney...........................................................        20
21.    Effectiveness Of Security...................................................        21
22.    Release Of Security.........................................................        22
23.    Set-Off.....................................................................        22
24.    Subsequent Security Interests...............................................        22
25.    Currency Indemnity..........................................................        23
26.    Assignment..................................................................        23
27.    Notices.....................................................................        23
28.    Expenses, Costs And Taxes...................................................        23
29.    Payments Free Of Deduction..................................................        24
30.    Discretion And Delegation...................................................        25
31.    Perpetuity Period...........................................................        25
32.    Governing Law...............................................................        25
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<TABLE>
<S>                                                                                        <C>
33.    Jurisdiction................................................................        25
34.    Counterparts................................................................        25

Schedule 1 THE COMPANIES...........................................................        27

Schedule 2 DETAILS OF REAL PROPERTY................................................        28
       Part A Registered Land......................................................        28
       Part B Unregistered Land....................................................        29

Schedule 3 DETAILS OF ASSIGNED ACCOUNTS............................................        30

Schedule 4 DETAILS OF SHARES.......................................................        31
       Part A        ..............................................................        31
       Part B        ..............................................................        34

Schedule 5           ..............................................................        38
       Part A Form Of Notice Of Assignment Of Assigned Accounts....................        38
       Part B Form Of Notice Of Assignment Of Intra-Group Loan.....................        42

Schedule 6           ..............................................................        45
       Part A Form Of Notice Of Charge To Landlords................................        45
       Part B Form Of Notice Of Charge Over Account................................        47
       Part C Form Of Notice Of Charge Over Monetary Claims........................        50

Schedule 7 FORM OF LEGAL MORTGAGE..................................................        53
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THIS DEBENTURE is made on 19 May 2003

BY

(1)      THE COMPANIES listed in Schedule 1 (The Companies) as companies (the
         "COMPANIES" and each a "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 or any Mortgage (as defined below) and in
         addition:

         "ACCOUNTS" means any credit balance from time to time on any account
         opened or maintained by any Company with any financial institution and
         all Related Rights and for the avoidance of doubt, includes the
         Assigned Accounts.

         "ASSIGNED ACCOUNTS" means each Escrow Account listed in Schedule 3
         (Details of Assigned Accounts) and all Related Rights.

         "AUSTRALIAN SHARES AND ASSETS" means the shares held by, to the order
         of or on behalf of Associated Electrical Industries Limited at any time
         in Marconi Australia Holdings Pty Limited, a company registered in
         Victoria with company number ABN 28 004 344 272 and all undertakings,
         assets and rights of any of the Companies (and in each case all Related
         Rights) which, as at the date of this Debenture, are located, or taken
         for the purposes of any Australian State or Territory stamp duty law to
         be located in Australia.

         "CHARGED PROPERTY" means all the assets of the Companies 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 and any Mortgage.

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

         "CONSENT PROPERTIES" means:

         (a)      leasehold property known as Area A, New Century Park, Coventry
                  more particularly described by the lease dated 24 August 2001
                  between Marconi Communications Limited (1) and Marconi (NCP)
                  Limited (2);

         (b)      leasehold property known as Area B, New Century Park, Coventry
                  more particularly described by the lease dated 24 August 2001
                  between Marconi Communications Limited (1) and Marconi (NCP)
                  Limited (2);

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         (c)      leasehold property known as Area C, New Century Park, Coventry
                  more particularly described by the lease dated 24 August 2001
                  between Marconi Communications Limited (1) and Marconi (NCP)
                  Limited (2);

         (d)      leasehold property known as Area D, New Century Park, Coventry
                  more particularly described by the lease dated 24 August 2001
                  between Marconi Communications Limited (1) and Marconi (NCP)
                  Limited (2);

         (e)      leasehold property known as New Horizon Park, Coventry more
                  particularly described by the lease dated 14 April 2003 and
                  made between Peter Edward Blackwell and Ronald Geoffrey
                  Sweetman as trustees of the Kodak Pension Plan (1) and Marconi
                  Communications Limited (2); and

         (f)      leasehold property known as 12th Floor, Exchange Tower, 1
                  Harbour Exchange Square, London Docklands, E1 more
                  particularly described by the lease dated 16 September 1998
                  and made between Dockways Limited (1) and Mobile Systems
                  International plc (2).

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

         "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 any 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 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.

                                     - 2 -

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         "INTRA-GROUP LOAN CONTRACTS" means any contracts between any Company
         and any other member of the Group pursuant to which that 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 any 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 (Company number
         00067307).

         "MONETARY CLAIMS" means any book and other debts and monetary claims
         owing to any 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 that
         Company is a party and any other assets, property, rights or
         undertaking of that Company and all Related Rights.

         "MORTGAGE" means a mortgage or charge in respect of Real Property in
         accordance with Clause 6 (Further Assurance) and Clause 11 (Real
         Property) substantially in the form of Schedule 7 (Form of Legal
         Mortgage).

         "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 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 5.

         "NOTICE OF CHARGE" means a notice of charge in substantially the form
         set out in Schedule 6.

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         "REAL PROPERTY" means:

         (d)      any freehold, leasehold, heritable or immovable property
                  (including the freehold and leasehold property in England and
                  Wales specified in Schedule 2 (Details of Real Property));

         (e)      any buildings, fixtures, fittings, fixed plant or machinery
                  from time to time situated on or forming part of such freehold
                  or leasehold property; and

         (f)      any present or future freehold, heritable or leasehold
                  property in which any company has an interest,

         and includes all Related Rights.

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

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

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

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

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

         (j)      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.

         "SCHEDULE 2 REAL PROPERTY" means the Real Property specified in
         Schedule 2 (Details of Real Property) and all Related Rights.

         "SECURED OBLIGATIONS" means, in relation to a Company, 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 Companies) at any time of the relevant
         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:

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

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

         (m)      any claim for damages or restitution; and

         (n)      any claim as a result of any recovery by a 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

                                     - 4 -

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         (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 Companies
         at any time and all Related Rights.

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

         "TANGIBLE MOVEABLE PROPERTY" means any plant, machinery, office
         equipment, computers, vehicles and other chattels (excluding any for
         the time being forming part of the Companies' 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 or any
                  Mortgage;

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

                                     - 5 -

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         1.2.3    any reference to the "SECURITY TRUSTEE", the "COMPANIES", any
                  "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      THIRD PARTY RIGHTS

         A person who is not a party hereto shall have no right under the
         Contracts (Rights of Third Parties) Act 1999 to enforce any term of
         this Debenture.

1.4      DUPLICATION

         To the extent that the provisions of the Debenture duplicate those of
         any Mortgage the provisions of that Mortgage shall prevail.

1.5      INCORPORATION OF PROVISIONS INTO ANY MORTGAGE

         Clauses 1.2 (Interpretation), 6.1 (Further Assurance: General), 6.3
         (Implied Covenants for Title), 14 (Enforcement of Security), 15
         (Extension and Variation of the Law of Property Act 1925), 16
         (Appointment of Receiver), 17 (Powers of Receiver), 20 (Power of
         Attorney), 32 (Governing Law) and 33 (Jurisdiction) of this Debenture
         are incorporated into any Mortgage as if expressly incorporated into
         that Mortgage, as if references in those clauses to this Debenture were
         references to that Mortgage and as if all references in those clauses
         to Charged Property were references to the assets of the Company
         granting the Mortgage from time to time charged in favour of, or
         assigned (whether at law or in equity) to the Security Trustee by or
         pursuant to that Mortgage.

1.6      MORTGAGE

         It is agreed that each Mortgage is supplemental to this Debenture.

1.7      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.

1.8      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

         Each 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 each Company shall pay to the
         Security Trustee when due and payable every sum at any time owing, due
         or incurred by that 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 neither such covenant

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         nor the security constituted by this Debenture nor any other provisions
         of this Debenture or any Mortgage shall extend to or include any
         liability or sum which would, but for this proviso, cause such
         covenant, security, or provision to be unlawful or prohibited by any
         applicable law (including, for the avoidance of doubt, Section 151 of
         the Companies Act 1985).

2.2      INTEREST ON DEMANDS

         If any Company fails to pay any sum on the due date for payment of that
         sum that 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
         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

         Each Company hereby charges with full title guarantee in favour of the
         Security Trustee as trustee for the Secured Creditors with the payment
         and discharge of the Secured Obligations, by way of first fixed charge
         (which so far as it relates to land in England and Wales vested in any
         Company at the date hereof shall be a charge by way of legal mortgage)
         all of its right, title and interest from time to time in and to each
         of the following assets:

         3.1.1    the Schedule 2 Real Property;

         3.1.2    the Tangible Moveable Property;

         3.1.3    any goodwill;

         3.1.4    all rights in relation to the uncalled capital of that
                  Company;

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

         3.1.6    all Monetary Claims deriving from or in relation to any
                  Intellectual Property or the proceeds of any Insurance Policy
                  relating to Schedule 2 Real Property.

3.2      ASSIGNMENTS

         Each Company hereby assigns with full title guarantee to the Security
         Trustee as trustee for the Secured Creditors as security for the
         payment and discharge of the Secured Obligations all its right, title
         and interest from time to time in and to each of the following assets
         (having already obtained any necessary consent to such assignment from
         any third party):

         3.2.1    all rights and claims in relation to any Assigned Account; and

         3.2.2    each of the Intra-Group Loan Contracts.

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3.3      FLOATING CHARGE

         Each Company hereby charges with full title guarantee in favour of the
         Security Trustee as trustee for the Secured Creditors with the payment
         and discharge of the Secured Obligations by way of first floating
         charge the whole of its 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 England and Wales, or of the jurisdiction in
         which that asset is situated, in favour of the Security Trustee as
         security for the Secured Obligations but specifically including within
         the floating charge hereby created the whole property, assets and
         undertaking of each Company situated in Scotland or otherwise governed
         by Scots law.

3.4      CASH COLLATERAL

         The security created by Clause 3.3 (Floating Charge) over the Accounts
         (other than the Mandatory Redemption Escrow Account) shall take effect
         subject to, and shall not restrict the ability of any 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.

3.5      AUSTRALIAN SHARES AND ASSETS

         For the avoidance of doubt, the Australian Shares and Assets shall not
         be charged by way of fixed or floating charge under this Debenture.

4.       CRYSTALLISATION OF FLOATING CHARGE

4.1      CRYSTALLISATION:  BY NOTICE

         By notice in writing to Marconi Corporation for and on behalf of the
         Companies, 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)

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         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 process, other than a
                  voluntary sale of Charged Property entered into by the
                  relevant 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, administration or re-organisation of any Company
                  or an administrator is appointed to any Company other than in
                  connection with a solvent reconstruction of any 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 for and on behalf of the Companies.

         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

         5.1.1    Marconi Corporation shall on the date hereof, deliver Notices
                  of Assignment duly executed by it or on its behalf and in
                  respect of each Assigned Account, to the Escrow Bank with whom
                  those Assigned Accounts are maintained and shall

                                     - 9 -

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                  use reasonable endeavours to procure an acknowledgement from
                  the Escrow Bank in the form attached thereto.

         5.1.2    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 any Company in
                  respect of the Intra-Group Loan Contracts.

5.2      NOTICES OF CHARGE

         5.2.1    Within 10 Business Days after the date of this Debenture, the
                  relevant Company or Companies will join the Security Trustee
                  in giving a Notice of Charge to all landlords and other
                  persons which are parties under all leases relating to the
                  Schedule 2 Real Property in existence on the date of this
                  Debenture and will use all commercially reasonable endeavours
                  to procure from each of such landlords and persons an
                  acknowledgment in the form attached thereto.

         5.2.2    If so required by the Security Trustee from time to time,
                  within 10 Business Days after any Company enters into any
                  fixed Security or any Mortgage in respect of any lease, the
                  relevant Company or Companies will join the Security Trustee
                  in giving a Notice of Charge to all such landlords and other
                  persons of the security constituted under this Debenture or
                  any Mortgage in respect of any such lease and will use all
                  commercially reasonable endeavours to procure from each of
                  such landlords and persons an acknowledgement in the form
                  attached thereto.

         5.2.3    Each Company shall within 10 Business Days after the date of
                  this Debenture, provide the Security Trustee with details of
                  all Accounts and Monetary Claims arising from any Insurance
                  Policy relating to Schedule 2 Real Property and deriving from
                  or relating to any Intellectual Property and in relation to
                  all other Accounts and Monetary Claims, 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 5.2.4 and/or sub-clause 5.2.5 below.

         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 relevant Company or
                  Companies in respect of any Monetary Claims.

         5.2.5    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

                                     - 10 -

<PAGE>

                  persons, Notices of Charge duly executed by the Security
                  Trustee on behalf of the relevant Company or Companies in
                  respect of any Accounts (other than the Assigned Accounts).

5.3      REAL PROPERTY:  DELIVERY OF DOCUMENTS OF TITLE

         Each Company shall within 10 Business Days of the date of the execution
         of this Debenture in relation to Schedule 2 Real Property, and upon the
         acquisition by that Company 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      NOTE OF MORTGAGE

         In the case of any Real Property, title to which is or will be
         registered under the Land Registration Acts 1925 to 1988, acquired by
         or on behalf of any Company after the execution of this Debenture, that
         Company shall promptly notify the Security Trustee of the title
         number(s) and, contemporaneously with the making of an application to
         H.M.L and Registry for the registration of that Company as the
         Registered Proprietor thereof, apply to H.M. Chief Land Registrar to
         enter a notice of any Mortgage on the Charges Register of such
         property.

5.5      FURTHER ADVANCES

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

         5.5.2    Each Company will apply promptly to H.M. Chief Land Registrar
                  to enter a note of the obligation to make further advances on
                  the Charges Register of any registered land forming part of
                  the Charged Property.

5.6      DELIVERY OF SHARE CERTIFICATES

         The Companies shall:

         5.6.1    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 listed in Part A of Schedule
                  4 (Details of Shares), and stock transfer forms in respect
                  thereof (executed in blank by or on behalf of the relevant
                  Company);

         5.6.2    use their commercially reasonable efforts to (which for the
                  avoidance of doubt shall include the replacement of lost or
                  destroyed documents) deposit with the Security Trustee or to
                  the order of the Security Trustee or with such Delegate as the
                  Security Trustee may appoint for this purpose (or procure the
                  deposit of) all certificates or other documents of title to
                  the Shares listed in Part B of Schedule 4 (Details of Shares)
                  and stock transfer forms in respect thereof (executed in blank
                  by or on behalf of the relevant Company) other than where such
                  shares are in a company which is (i) a dormant company; or
                  (ii) Stanhope Investment

                                     - 11 -

<PAGE>

                  Management Ltd company registration number 02209765 and
                  Stanhope Pension Services Limited company registration number
                  03268021; or (iii) a company in which the relevant shareholder
                  Company owns 50% or less of the called up share capital of
                  such company; and

         5.6.3    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 relevant Company) in respect
                  thereof PROVIDED THAT this obligation shall only apply in
                  respect of stocks, shares, warrants or other securities in
                  respect of or derived from the Shares, the certificates or
                  other documents of title of which are required to be deposited
                  with or to the order of the Security Trustee or such Delegate
                  as the Security Trustee may appoint for this purpose pursuant
                  to sub-clauses 5.6.1 and 5.6.2 above.

6.       FURTHER ASSURANCE

6.1      FURTHER ASSURANCE: GENERAL

         Each Company shall promptly enter into a Mortgage over any Real
         Property and 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 that 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 that Company located in any jurisdiction outside
                  England and Wales 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 in England and Wales shall be a
                  charge by way of legal mortgage) over all its right, title and
                  interest from time to time in any Real Property (including
                  using all reasonable endeavours to obtain any requisite third
                  party consent); and/or

         6.1.4    to facilitate the realisation of the Charged Property.

6.2      NECESSARY ACTION

         If so requested by the Security Trustee each Company shall take all
         such action as is available to it (including making all filings and
         registrations) as may be necessary for the purpose of the creation,
         perfection, protection or maintenance of any Security conferred

                                     - 12 -

<PAGE>

         or intended to be conferred on the Security Trustee by or pursuant to
         this Debenture and any Mortgage.

6.3      IMPLIED COVENANTS FOR TITLE

         The obligations of each Company under this Debenture and any Mortgage
         shall be in addition to the covenants for title deemed to be included
         in this Debenture and any Mortgage by virtue of (insofar as applicable)
         Part 1 of the Law of Property (Miscellaneous Provisions) Act 1994.

6.4      CONSENT PROPERTIES

         Each Company with an interest in the Consent Properties shall in
         relation to the Consent Properties:

         6.4.1    use all reasonable endeavours (including payment of reasonable
                  fees, costs and expenses and compliance with any landlord's
                  reasonable requests) to obtain the consent of landlords and
                  the consent of any other third party that is required for the
                  creation of a first legal mortgage in the form of the Mortgage
                  or, as appropriate, a first ranking standard security in
                  respect of the relevant Consent Property as soon as possible
                  after the date hereof and, in any event, within three months
                  of the date hereof;

         6.4.2    keep the Security Trustee informed on request of the progress
                  of its negotiations with the landlord or any such third party
                  and produce to the Security Trustee a copy of each consent
                  forthwith upon its receipt; and

         6.4.3    following receipt of the consent referred to in sub-clause
                  6.4.1, promptly execute and deliver to the Security Trustee a
                  first legal mortgage in the form of the Mortgage or, as
                  appropriate, a first ranking standard security in respect of
                  the relevant Consent Property.

7.       NEGATIVE PLEDGE AND DISPOSALS

7.1      NEGATIVE PLEDGE

         Each Company undertakes that it shall not, at any time during the
         subsistence of this Debenture or any Mortgage, 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

         Each Company undertakes that it shall not (and shall not agree to) at
         any time during the subsistence of this Debenture or any Mortgage,
         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

                                     - 13 -

<PAGE>

                  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:  REPRESENTATION

         The Companies represent and warrant to the Security Trustee that:

         8.1.1    they are the sole legal and beneficial owners of the Shares in
                  Part A of Schedule 4 free from any Security (as such term is
                  defined in the Security Trust and Intercreditor Deed) except
                  as created by this deed; and

         8.1.2    the Shares in Part A of Schedule 4 are fully paid up (save in
                  relation to the L1 share that Marconi Corporation owns in
                  Highrose Limited).

8.2      SHARES:  BEFORE ENFORCEMENT EVENT

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

         8.2.1    be entitled to retain all dividends, interest and other monies
                  arising from its Shares; and

         8.2.2    exercise all voting rights in relation to its Shares PROVIDED
                  THAT a 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).

8.3      SHARES:  AFTER ENFORCEMENT EVENT

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

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

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

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

                                     - 14 -

<PAGE>

         8.3.4    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

         Each 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 (other than an Assigned 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, no
         Company shall 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      ASSIGNED ACCOUNTS

         9.3.1    No Company shall be entitled to receive, withdraw or otherwise
                  transfer any credit balance from time to time on any Assigned
                  Account except with the prior consent of the Security Trustee
                  or as permitted pursuant to the terms of the Escrow Agreement.

         9.3.2    The Security Trustee shall, upon the occurrence of an
                  Enforcement Event and at any time thereafter while such
                  Enforcement Event is continuing, be entitled without notice to
                  exercise from time to time all rights, powers and remedies
                  held by it as assignee of the Assigned Accounts and to:

                  (a)      demand and receive all and any monies due under or
                           arising out of each Assigned Account; and

                                     - 15 -

<PAGE>

                  (b)      exercise all such rights as any Company might, in
                           relation to such Assigned Account, exercise but for
                           the terms of this Debenture.

9.4      ACCOUNTS:  APPLICATION OF MONIES

         The Security Trustee shall, upon the occurrence of an Enforcement Event
         and at any time thereafter while 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).

10.      MONETARY CLAIMS

10.1     DEALING WITH MONETARY CLAIMS

         No Company shall 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 3.1.6
                  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 3.1.6 of Clause 3.1 (Fixed Charges)
                  into the Accounts (other than the Assigned Accounts), the
                  Assigned Accounts to the extent such proceeds are required to
                  be deposited in the Assigned Accounts pursuant to the
                  Indentures or as the Security Trustee may require (and such
                  proceeds shall be held upon trust by the relevant Company or
                  Companies 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 3.1.6 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 or the
         proceeds of any Insurance Policy relating to Real 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 a Company shall be entitled to withdraw such
         proceeds from such Account (other than an Assigned 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.

                                     - 16 -

<PAGE>

11.      REAL PROPERTY

11.1     PROPERTY: NOTIFICATION

         Each Company shall promptly notify the Security Trustee of any
         contract, conveyance, transfer or other disposition for the acquisition
         by that Company (or its nominee(s)) of any Real Property and shall
         promptly enter into a Mortgage over such Real Property if so required
         by the Security Trustee.

11.2     ENTITLEMENT TO REMEDY

         If any 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 by that 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.      INTRAGROUP LOAN CONTRACTS

         Prior to the delivery of a Notice of Assignment pursuant to sub-clause
         5.1.2 of Clause 5.1 (Notices of Assignment) or the occurrence of an
         Enforcement Event, each 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.

13.      INVESTMENTS: DELIVERY OF DOCUMENTS OF TITLE

         After the occurrence of an Enforcement Event, each 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 that 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).

14.      ENFORCEMENT OF SECURITY

14.1     ENFORCEMENT

         At any time after the occurrence of an Enforcement Event and the
         Security Trustee (acting on instructions received pursuant to the terms
         of the Security Trust and Intercreditor Deed) giving notice to Marconi
         Corporation 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 Law of Property Act 1925 (as varied or extended by this
                  Debenture) insofar as applicable on mortgagees and by this

                                     - 17 -

<PAGE>

                  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.

15.      EXTENSION AND VARIATION OF THE LAW OF PROPERTY ACT 1925

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 Section 101 of the Law of Property Act 1925 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 Sections 93 and 103 of the Law of
         Property Act 1925 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 any Company
         on or at any time after the occurrence of an Enforcement Event.

15.3     POWER OF LEASING

         The statutory powers of leasing may be exercised by the Security
         Trustee at any time on or after the occurrence of an Enforcement Event
         and the Security Trustee and any Receiver may make any lease or
         agreement for lease, accept surrenders of leases and grant options on
         such terms as it shall think fit, without the need to comply with any
         restrictions imposed by Sections 99 and 100 of the Law of Property Act
         1925.

16.      APPOINTMENT OF RECEIVER

16.1     APPOINTMENT AND REMOVAL

         After the occurrence of an Enforcement Event or if a petition or
         application is presented for the making of an administration order in
         relation to any Company or if any Company or any other person gives
         written notice of its intention to appoint an administrator to any
         Company or if requested to do so by any Company, the Security Trustee
         may by deed or otherwise (acting through an authorised officer of the
         Security Trustee), without prior notice to any 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).

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<PAGE>

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;

         16.2.2   for all purposes shall be deemed to be the agent of the
                  relevant Company which 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 (without being
                  limited to the maximum rate specified by the Law of Property
                  Act 1925).

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 Law of Property Act 1925 (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.

16.4     ENTERPRISE ACT 2002

         For the avoidance of doubt, paragraph 2 of Section 14 of Schedule 16 to
         the Enterprise Act 2002 shall apply to the floating charge created
         pursuant to Clause 3.3 (Floating Charge).

17.      POWERS OF RECEIVER

         Every Receiver shall (subject to any restrictions in the instrument
         appointing him but notwithstanding any winding-up or dissolution of any
         Company) have and be entitled to exercise, in relation to the Charged
         Property (and any assets of any 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 any Company or in his own name and, in each case, at the cost
         of the Companies):

         17.1.1   insofar as applicable all the powers conferred by the Law of
                  Property Act 1925 on mortgagors and on mortgagees in
                  possession and on receivers appointed under that Act;

         17.1.2   all the powers of an administrative receiver set out in
                  Schedule 1 to the Insolvency Act 1986 (whether or not the
                  Receiver is an administrative receiver);

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

         17.1.4   the power to do all things (including bringing or defending
                  proceedings in the name or on behalf of any 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

                                     - 19 -

<PAGE>

                  to his hands any assets of the Companies forming part of, or
                  which when got in would be, Charged Property.

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 Law of Property Act 1925) 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 any 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

         Each Company by way of security irrevocably 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:

         20.1.1   carrying out any obligation imposed on that 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 any Mortgage 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

         Each 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.

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<PAGE>

20.3     INDEMNITY

         Each 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 and any Mortgage
         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 any Mortgage
         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 and any Mortgage.

21.3     NO PREJUDICE

         The security created by or pursuant to this Debenture and any Mortgage
         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 any 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 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 any Mortgage 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 or any Mortgage is or
         becomes illegal, invalid or unenforceable in any respect under the law
         of any jurisdiction, neither the

                                     - 21 -

<PAGE>

         legality, validity or enforceability of the remaining provisions of
         this Debenture or any Mortgage 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 or any Mortgage is invalid, unenforceable or
         ineffective for any reason, that shall not affect or impair any other
         part of the security.

21.7     COMPANIES' OBLIGATIONS

         The obligations of each 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 any Company hereunder.

22.      RELEASE OF SECURITY

         The Security Trustee shall, at the cost of the Companies, release and
         cancel the security constituted by this Debenture and procure the
         reassignment to the relevant 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.

23.      SET-OFF

         Each 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 that 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 any Mortgage or the Indentures, all payments
         thereafter by or on behalf of any Company

                                     - 22 -

<PAGE>

         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 that 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 any Company under this Debenture or any
         Mortgage or any order or judgment given or made in relation to this
         Debenture or any Mortgage 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 that 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 any Mortgage; or

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

         the Companies 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 or any Mortgage in accordance with
         the Security Trust and Intercreditor Deed. The Security Trustee shall
         be entitled to disclose such information concerning the Companies and
         this Debenture or any Mortgage 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.

27.      NOTICES

         Each communication to be made under this Debenture or any Mortgage
         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

         Each 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) incurred in relation to such Company on
         a full indemnity basis together with any applicable VAT 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:

                                     - 23 -

<PAGE>

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

         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).

         In the event that such costs and expenses cannot be attributed to a
         specific Company, then such costs and expenses shall be borne by
         Marconi Corporation.

28.2     TAXES

         Each 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 or
         any Mortgage, 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 any Company or any delay by any 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 or any Mortgage shall be made free
         and clear of and without set-off or deduction for or on account of tax
         unless a Company is required to make such payment subject to the
         deduction or withholding of tax, in which case the sum payable by that
         Company in 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.

                                     - 24 -

<PAGE>

30.      DISCRETION AND DELEGATION

30.1     DISCRETION

         Any liberty or power which may be exercised or any determination which
         may be made hereunder or under any Mortgage 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) or any Mortgage 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 English law.

33.      JURISDICTION

33.1     ENGLISH COURTS

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

33.2     CONVENIENT FORUM

         The parties agree that the courts of England 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 (English Courts), it does not
         prevent the Security Trustee from taking proceedings relating to a
         Dispute in any other courts with jurisdiction. To the extent allowed by
         law the Security Trustee may take concurrent proceedings in any number
         of jurisdictions.

34.      COUNTERPARTS

         This Deed 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

                                     - 25 -

<PAGE>

         were on a single copy of this Deed. Any party may enter into this Deed
         by signing any such counterpart.

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

                                     - 26 -

<PAGE>

                                   SCHEDULE 1
                                  THE COMPANIES

<TABLE>
<CAPTION>
Company name                                                          Company number
<S>                                                                   <C>
Associated Electrical Industries Limited                                 00062919
Elliott-Automation Holdings Limited                                      00559725
English Electric Company Limited                                         00152250
GPT Special Projects Management Limited                                  02984211
Highrose Limited                                                         04410334
Marconi (Bruton Street) Limited                                          04129430
Marconi (DGP1) Limited                                                   03545378
Marconi (DGP2) Limited                                                   03545363
Marconi (Elliott Automation) Limited                                     00487190
Marconi (NCP) Limited                                                    03739989
Marconi Aerospace Unlimited                                              00516425
Marconi Bonding Limited                                                  03818628
Marconi Communications China Limited                                     02956293
Marconi Communications Holdings Limited                                  00319092
Marconi Communications International Holdings Limited                    02204070
Marconi Communications International Investments Limited                 02203912
Marconi Communications International Limited                             00464439
Marconi Communications Investments Limited                               02353798
Marconi Communications Limited                                           00703317
Marconi Corporation plc                                                  00067307
Marconi Optical Components Limited                                       03694360
Marconi UK Intellectual Property Limited                                 04573518
Metapath Software International Limited                                  02436108
Mobile Systems International Holdings Limited                            03179118
</TABLE>

                                     - 27 -

<PAGE>

                                   SCHEDULE 2
                            DETAILS OF REAL PROPERTY

                                     PART A
                                 Registered Land

        (Freehold or leasehold property (if any) in England and Wales of
                 which the relevant Company is registered as the
                        proprietor at H.M. Land Registry)

<TABLE>
<CAPTION>
                                                                           TITLE NUMBER, DISTRICT AND
REGISTERED PROPRIETOR                   DESCRIPTION OF PROPERTY                      COUNTY
<S>                                     <C>                                <C>
Marconi Communications                  Leasehold property known as        LA114301
International Holdings Limited          land and buildings on the
                                        South East side of Carr Lane,      Chorley, Lancashire
                                        Chorley

Marconi Communications                  Leasehold property known as        MS49631
Limited                                 land and buildings on the
                                        North East side of Wilson          Knowsley, Merseyside
                                        Road, Huyton, Liverpool

Marconi Corporation plc                 Leasehold property known as        EGL398383
                                        Maryland House, 329-333
                                        High Street, Stratford,            London Borough of
                                        London                             Newham, Greater London

Marconi Communications                  Freehold property at 18/20         NN5272
Limited                                 Dennington Road,
                                        Wellingborough,                    Wellingborough,
                                        Northamptonshire                   Northamptonshire
</TABLE>

                                     - 28 -

<PAGE>

                                     Part B
                                Unregistered Land

(Freehold or leasehold property (if any) in England and Wales title to which is
not registered at H.M. Land Registry of which the relevant Company is the owner)

<TABLE>
<CAPTION>
Property-owning Company                 Description of Property            Details of Lease/Root of
                                                                                    Title
<S>                                     <C>                                <C>
Marconi Communications Limited          Leasehold property known as        Lease dated 28 June 2002 and
                                        Building 51, Edge Lane,            made between Marconi
                                        Liverpool                          Communications International
                                                                           Holdings Limited (1) and Marconi
                                                                           Communications Limited (2)

Marconi Communications Limited          Leasehold property known as        Lease dated 28 June 2002 and
                                        Building 19, Edge Lane, Liverpool  made between Marconi
                                                                           Communications International
                                                                           Holdings Limited (1) and Marconi
                                                                           Communications Limited (2)

Marconi Communications Limited          Leasehold property known as        Lease dated 28 June 2002 and
                                        Buildings 55/22, Edge Lane,        made between Marconi
                                        Liverpool                          Communications International
                                                                           Holdings Limited (1) and Marconi
                                                                           Communications Limited (2)

Marconi Communications Limited          Leasehold property known as        Lease dated 28 June 2002 and
                                        Ground Floor, Building 2,          made between Marconi
                                        Edge Lane, Liverpool               Communications International
                                                                           Holdings Limited (1) and Marconi
                                                                           Communications Limited (2)

Marconi Communications Limited          Leasehold property known as        Lease dated 28 June 2002 and
                                        Building 21, Edge Lane, Liverpool  made between Marconi
                                                                           Communications International
                                                                           Holdings Limited (1) and Marconi
                                                                           Communications Limited (2)
</TABLE>

                                     - 29 -

<PAGE>

                                   SCHEDULE 3
                          DETAILS OF ASSIGNED ACCOUNTS

<TABLE>
<CAPTION>
Bank                      Currency        Swift/        Account        Account Name/Reference
                                        Sort Code       Number
<S>                       <C>           <C>             <C>            <C>
HSBC Bank plc               GBP         40 05 30        73666654       Marconi Corporation plc
                                                                       Mandatory Redemption Escrow
                                                                       Account - Deposit Account
                            EUR         40 05 15        57850201       Marconi Corporation plc
                                                                       Mandatory Redemption Escrow
                                                                       Account - Call Account
                            USD         40 05 15        57850236       Marconi Corporation plc
                                                                       Mandatory Redemption Escrow
                                                                       Account - Call Account

HSBC Bank plc               GBP         40 05 30        73666662       Marconi Corporation plc Existing
                                                                       Performance Bond Escrow
                                                                       Account - Client Deposit Account
                            EUR         40 05 15        57850228       Marconi Corporation plc Existing
                                                                       Performance Bond Escrow
                                                                       Account - Call Account
                            USD         40 05 15        57850244       Marconi Corporation plc Existing
                                                                       Performance Bond Escrow
                                                                       Account - Call Account
</TABLE>

                                     - 30 -

<PAGE>

                                   SCHEDULE 4
                                DETAILS OF SHARES

                                     Part A

<TABLE>
<CAPTION>

                                                 Description and    Percentage
                             Issued Capital         Number of       of Shares
Name of Company                  Share             Shares Held         Held     Share Certificate Numbers(s)
<S>                          <C>                 <C>                <C>         <C>
Associated Electrical         L43,428,595        Ord.L1.00 x           100      30624 - 1 share
Industries Limited                                43,428,595                    30623 - 3,000 shares
                                                                                30477 - 27,501,392 shares
                                                                                30478 - 9,764,898 shares
                                                                                30580 - 3,392,068 shares
                                                                                30588 - 706,153 shares
                                                                                30593 - 1,068,933 shares
                                                                                30594 - 750,306 shares
                                                                                30597 - 237,845 shares
                                                                                30619 - 3,499 shares
                                                                                30620 - 500 shares

Bookham                         L892,864         Ord. 0.03p x            9      0024380
Technology plc (UK)                               12,891,000

Easynet Group plc              L4,436,990        Ord. 0.04p x         49.8%     A07095 - 28,954,516 shares
                                                  30,111,162                    A07362 - 1,156,646 shares

                                                  Convertible                   A00001 - 48,553,661 shares
                                                 Ord.0.04.p x                   A00002 - 2,153,489 shares
                                                  50,707,150

Elliott Automation               L1,000          Ord.L1.00 x           100      6 - 998 shares
Holdings Limited                                    1,000                       26 - 1 share
                                                                                26 - 1 share (Same number
                                                                                used on different certificate)

The English Electric           L88,142,081       Ord.L1.00 x           100      085843 - 1 share
Company Ltd                                       88,142,081                    085832 - 80,612,496 shares
                                                                                085833 - 7,529,579 shares
                                                                                085840 - 1 share
                                                                                085841 - 1 share
                                                                                085842 - 3 shares

GPT Special Projects               L2            Ord.L1.00 x 2         100      1- 1 share
Management Limited                                                              2 - 1 share

Highrose Limited                   L1            Ord.L1.00 x 1         100      1 - 1 share
</TABLE>

                                     - 31 -

<PAGE>

<TABLE>
<CAPTION>
                                                Description And       Percentage
Name of Company             Issued Capital         Number of          of Shares
                                Share             Shares Held            Held      Share Certificate Numbers(s)
<S>                         <C>                 <C>                   <C>         <C>
Marconi (Bruton Street)       L780,001            Ord.L1.00 x            100      2 - 1 share
Limited                                             780,001                       3 - 780,000 shares

Marconi (DGP1) Limited        L845,000            Ord.L1.00 x            100      11 - 600,000 shares
                                                    845,000                       10 - 40,000 shares
                                                                                  9 - 102,500 shares
                                                                                  8 - 2,500 shares
                                                                                  7 - 99,996 shares
                                                                                  6 - 2 shares
                                                                                  5 - 1 share
                                                                                  3 - 1 share

Marconi (DGP2) Limited        L845,000            Ord.L1.00 x            100      11 - 600,000 shares
                                                    845,000                       10 - 40,000 shares
                                                                                  9 - 102,500 shares
                                                                                  8 - 2,500 shares
                                                                                  7 - 99,996 shares
                                                                                  6 - 2 shares
                                                                                  5 - 1 share
                                                                                  3 - 1 share

Marconi (Elliot               L18,582,153         Ord.L0.25 x            100      531 - 2,091,876 shares
Automation) Limited                               74,328,612                      532 - 141,612 shares
                                                                                  533 - 808 shares
                                                                                  534 - 5,704 shares
                                                                                  5776 - 15,149,064 shares
                                                                                  5777 - 1,025,616 shares
                                                                                  5778 - 228,120 shares
                                                                                  178562 - 2,892,614 shares
                                                                                  178572 - 50,164,610 shares
                                                                                  178581 - 2,624,588 shares
                                                                                  178582 - 1,600 shares
                                                                                  178602 - 400 shares
                                                                                  178604 - 1,599 shares
                                                                                  178598 - 400 shares and
                                                                                  178603 - 1 share

Marconi (NCP) Limited             L1            Ord.L1.00 x 1            100      2 - 1 share

Marconi Bonding Limited           L1            Ord.L1.00 x 1            100      2 - 1 share
</TABLE>

                                     - 32 -

<PAGE>

<TABLE>
<CAPTION>
                                                   Description and       Percentage
                             Issued Capital           Number of          of Shares
Name of Company                  Share               Shares Held           Held       Share Certificate Numbers(s)
<S>                         <C>                    <C>                   <C>          <C>
Marconi                           L2               Ord.L1.00 x 2            100          1 - 1 share
Communications                                                                           2 - 1 share
China Limited

Marconi                     L200,000,000            Ord.L1.00 x             100          4 - 50 shares
Communications                                      200,000,000                          8 - 19,999,950 shares
Holdings Limited                                                                         10 - 100,000,000 shares
                                                                                         13 - 79,999,999 shares
                                                                                         14 - 1 share

Marconi                         L100               Ord.L1.00 x 1            100          1 - 1 share
Communications                                        100                                4 - 99 shares
International
Holdings Limited

Marconi                     L200,000,000            Ord.L1.00 x             100          1 - 199,999,999 shares
Communications                                      200,000,000                          2 - 1 share
International
Investments Limited

Marconi                         L100               Ord.L1.00 x 1            100          1 - 99 shares
Communications                                         100                               3 - 1 share
International Limited

Marconi                          L2                Ord.L1.00 x 2            100          2 - 1 share
Communications                                                                           3 - 1 share
Investments Limited

Marconi                      L1,500,000             Ord.L1.00 x             100          1 - 1 share
Communications                                       1,500,000                           2 - 1,499,999 shares
Limited

Marconi Optical                  L2                Ord.L1.00 x 2            100          2 - 2 shares
Components Limited

Marconi UK                       L1                Ord.L1.00 x 2            100          1 - 1 share
Intellectual Property
Limited

Metapath Software             L292,500             Ord.L0.025 x             100          1 - 11,700,000 shares
International Limited                               11,700,000
</TABLE>

                                     - 33 -

<PAGE>

                                     PART B

<TABLE>
<CAPTION>
-------------------------------------------------------------------------------------------------------------------------------
                                  Issued Share                     Description And Number of Shares Held
     Name of Company                Capital                    (ordinary L1.00 shares unless otherwise stated)         % Owned
-------------------------------------------------------------------------------------------------------------------------------
<S>                             <C>                  <C>                                                               <C>
Arrow Ltd                           L50,000          Associated Electrical Industries Limited - 49,000                    100
                                                     Associated Electrical Industries Holdings Limited - 1,000
-------------------------------------------------------------------------------------------------------------------------------
Associated Electrical               L2,500           Associated Electrical Industries Limited - 2,499                     100
Industries International                             Associated Electrical Industries Holdings Limited - 1
Ltd
-------------------------------------------------------------------------------------------------------------------------------
FF Chrestien & Co Ltd               L25,000          Associated Electrical Industries Limited - 24,999                    100
                                                     Associated Electrical Industries Holdings Limited - 1
-------------------------------------------------------------------------------------------------------------------------------
Marconi Projects                      L3             Associated Electrical Industries Limited - 2                         100
Hong Kong Ltd                                        Associated Electrical Industries Holdings Limited - 1
-------------------------------------------------------------------------------------------------------------------------------
Associated                        L1,400,000         Elliott-Automation Holdings Limited - 2,799,998 ordinary 50p         100
Automation Ltd                      ord 50p          shares
                                                     Associated Electrical Industries
                                                     Holdings Limited - 1 ordinary 50p
                                                     share The English Electric Company,
                                                     Limited - 1 ordinary 50p share
-------------------------------------------------------------------------------------------------------------------------------
Marconi (Holdings) Ltd             L996,094          Elliott-Automation Holdings Limited - 3,983,975 ordinary 25p         100
                                   ord 25p           shares
                                 L500,000 5%         Associated Electrical Industries Holdings Limited - 400
                                 Cum Pref L1         ordinary 25p shares
                                                     Associated Electrical Industries Limited - 1 ordinary 25p
                                                     share
                                                     Elliott-Automation Holdings Limited - 500,000 5% Cumulative
                                                     Preference shares of L1
-------------------------------------------------------------------------------------------------------------------------------
Combined Electrical               L2,332,000         The English Electric Company, Limited - 11,659,498 ordinary          100
Manufacturers Ltd                  20p ord           20p shares
                                                     Associated Electrical Industries Holdings Limited - 501
                                   L350,000          ordinary 20p shares
                                4.25% Cum Pref       Associated Electrical Industries Limited - 1 ordinary 20p
                                     L1              share
                                                     The English Electric Company, Limited - 350,000 4.25%
                                                     Cumulative Preference shares of L1
-------------------------------------------------------------------------------------------------------------------------------
The Kingsway Housing               L500,000          The English Electric Company, Limited - 499,999                      100
Association Ltd                                      Associated Electrical Industries Holdings Limited - 1
-------------------------------------------------------------------------------------------------------------------------------
Zipbond Ltd                     L10 ord L1           The English Electric Company, Limited - 9 ordinary L1 shares         100
                                    90 10%           Associated Electrical Industries Holdings Limited - 1
                                   non-cum           ordinary L1 share
                                   pref L1           The English Electric Company, Limited - 90 10%
                                                     non-cumulative preference shares of L1
-------------------------------------------------------------------------------------------------------------------------------
Mobile Systems Services            L10,000           Metapath Software International Limited - 5,001                      100
Limited                                              Mohamid Ibrahim & Metapath Software International Ltd - 4,999
-------------------------------------------------------------------------------------------------------------------------------
GPT Middle East Ltd               L100,000           Marconi Communications International Investments - 99,999            100
                                                     Marconi Communications Optical Fibres Limited - 1
-------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                     - 34 -

<PAGE>

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------------------------
                                Issued Share                      Description And Number of Shares Held                % Owned
     Name of Company              Capital                    (ordinary L1.00 shares unless otherwise stated)
------------------------------------------------------------------------------------------------------------------------------
<S>                          <C>                     <C>                                                               <C>
Oxus Mining plc               L1,810,493.16          Marconi Communications International Holdings Limited -                <1
                                                     2,188,320 ordinary lp shares
-------------------------------------------------------------------------------------------------------------------------------
Telephone Cables Ltd            L2,500,000           Marconi Communications International Investments Limited -           100
                                                     1,676,250
                                                     Marconi Communications International Limited - 573,750
------------------------------------------------------------------------------------------------------------------------------
Marconi Communications             L100              GPT Middle East Limited (held on behalf of Marconi                   100
C.I.S. Ltd                                           Communications Limited) - 99
                                                     Marconi Communications Optical Fibres Limited - 1
------------------------------------------------------------------------------------------------------------------------------
Marconi Defence Overseas            L2               Marconi Communications Limited - 2                                   100
Ltd
------------------------------------------------------------------------------------------------------------------------------
Rural Radio Systems Ltd           L6,219             Marconi Communications Ltd - 622                                      10
------------------------------------------------------------------------------------------------------------------------------
Tetrel Ltd                       24,348,35           Marconi Communications Limited - 485,987 "A" Ordinary 0.05p          100
                               "A" Ord 0.05p         shares
------------------------------------------------------------------------------------------------------------------------------
Albany Partnership Ltd          L1,260,000           Marconi Corporation plc - 1,260,000                                  100
------------------------------------------------------------------------------------------------------------------------------
Bruton Street                   L1,000,000           Marconi Corporation plc - 999,999                                    100
Investments Ltd                                      Associated Electrical Industries Holdings Limited - 1
------------------------------------------------------------------------------------------------------------------------------
Confirmant Ltd                   30,000,000          Marconi Corporation plc - 15,000,000                                 50
------------------------------------------------------------------------------------------------------------------------------
Highspeed Office Ltd         L197.89 ord 0.1p        Marconi Corporation plc - 10,416 "A" preferred shares of 0.lp         15
                             L10.42 "A" pref         Marconi Corporation plc - 130,198 "B" preferred ordinary
                                ord 0.1p             shares of 0.1p
                              L398.41 "B"
                             pref ord 0.1p
                                L312.47
                             convertible 0.1p
------------------------------------------------------------------------------------------------------------------------------
Layana Ltd                          L1               Marconi Corporation plc - 1                                          100
------------------------------------------------------------------------------------------------------------------------------
Marconi (Sixty-Nine) Ltd          L325,000           Marconi Corporation plc - 324,999                                    100
                                                     Associated Electrical Industries Holdings Limited - 1
------------------------------------------------------------------------------------------------------------------------------
Marconi (Fifteen) Ltd               L2               Marconi Corporation plc - 1                                          100
                                                     Associated Electrical Industries Holdings Limited - 1
------------------------------------------------------------------------------------------------------------------------------
Marconi (Forty-Six) Ltd            L102              Marconi Corporation plc - 100                                        100
                                                     Associated Electrical Industries Holdings Limited - 2
------------------------------------------------------------------------------------------------------------------------------
Marconi (Forty-Three)               L1               Marconi Corporation plc- 1                                           100
Limited
------------------------------------------------------------------------------------------------------------------------------
Marconi (Sixteen) Ltd           L1,250,000           Marconi Corporation plc - 1,249,999                                  100
                                                     Associated Electrical Industries Holdings Limited - 1
------------------------------------------------------------------------------------------------------------------------------
Marconi (Thirty-Two) Ltd            L2               Marconi Corporation plc - 2                                          100

------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                     - 35 -

<PAGE>

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------------------------
                               Issued Share                      Description and Number of Shares Held
     Name of Company             Capital                    (ordinary L1.00 shares unless otherwise stated)           % Owned
------------------------------------------------------------------------------------------------------------------------------
<S>                         <C>                      <C>                                                              <C>
Marconi (Twenty-Seven)         L450,000 ord          Marconi Corporation plc - 1,799,199 ordinary 25p shares              100
Ltd                         25p 800,000 conv         Associated Electrical Industries Holdings Limited - 1
                                 ord 25p             ordinary 25p share
                                                     C G Donaldson - 400 ordinary 25p shares
                             292,500 6% cum          K D Smith - 400 ordinary 25p shares
                                pref L1              Marconi Corporation plc - 3,200,000 convertible
                                                     ordinary 25p shares
                                                     Marconi Corporation plc - 292,500 6% cumulative preference
                                                     shares of L1
------------------------------------------------------------------------------------------------------------------------------
Marconi (WCGL) Ltd            L2,300,000 ord         Marconi Corporation plc - 11,499,999 ordinary 20p shares             100
                                  20p                Associated Electrical Industries Holdings Limited - 1
                                                     ordinary 20p share
------------------------------------------------------------------------------------------------------------------------------
Marconi Capital Ltd               L2                 Marconi Corporation plc - 2                                          100
------------------------------------------------------------------------------------------------------------------------------
Marconi Caswell                   L1                 Marconi Corporation plc - 1                                          100
Developments Ltd
------------------------------------------------------------------------------------------------------------------------------
Marconi Finance plc            L10,050,000           Marconi Corporation plc - 10,049,999                                 100
                                                     Clanville Limited - 1
------------------------------------------------------------------------------------------------------------------------------
Marconi Fleet Management         L100                Marconi Corporation plc - 99                                         100
Ltd                                                  Associated Electrical Industries Holdings Limited - 1
------------------------------------------------------------------------------------------------------------------------------
Marconi G.M. Ltd                  L2                 Marconi Corporation plc - 2                                          100
------------------------------------------------------------------------------------------------------------------------------
Marconi India Ltd              L50,000               Marconi Corporation plc - 49,999                                     100
                                                     Associated Electrical Industries Holdings Limited - 1
------------------------------------------------------------------------------------------------------------------------------
Marconi Information            L78,852               Marconi Corporation plc - 78,852                                     100
Systems Ltd
------------------------------------------------------------------------------------------------------------------------------
Marconi Mobile Systems           L100                Marconi Corporation plc - 99                                         100
Ltd                                                  Associated Electrical Industries Holdings Limited - 1
------------------------------------------------------------------------------------------------------------------------------
Marconi (Nine) Ltd               L100                Marconi Corporation plc - 99                                         100
                                                     Associated Electrical Industries Holdings Limited - 1
------------------------------------------------------------------------------------------------------------------------------
Marconi Quest Ltd                 L1                 Marconi Corporation plc#- 1                                          100
(Trustee Co.)
------------------------------------------------------------------------------------------------------------------------------
Marconi Rolls-Royce           L2,000,000             Marconi Corporation plc - 1,000,000                                   50
(Power Generation) Ltd
------------------------------------------------------------------------------------------------------------------------------
Netdecisions Holdings Ltd        L128,571            Marconi Corporation plc - 17,128,381 deferred 0.25p shares             1
                                ord L1               Marconi Corporation plc - 1,200,000 ordinary 0.25p shares
                                L42,820,95
                              deferred 0.25p
                              L226,643,14 ord
                                  0.25p
------------------------------------------------------------------------------------------------------------------------------
Netscient Ltd                  128,571               Marconi Corporation plc - 128,571 ordinary L1                        100
                                ord L1               Marconi Corporation plc - 35,065 'A' ordinary L1
                            35,065 'A' ord           Marconi Corporation p1c - 115,200,000 lp preference shares
                                  L1
                            115,200,000 1p
                                 pref
------------------------------------------------------------------------------------------------------------------------------
Oxford G1ycoSciences plc     L2,800,133.75           Marconi Corporation plc - 645,162                                    1.1
                                ord 5p
------------------------------------------------------------------------------------------------------------------------------
Plessey Holdings Ltd          L265,000,500           Marconi Corporation plc - 300,500,000 'G' ordinary L1                 50
                             'G' ord L1
                              L265,000,500
                             'S' ord L1
------------------------------------------------------------------------------------------------------------------------------
Regent Escrow Ltd                L100                Marconi Corporation plc - 1                                          100
------------------------------------------------------------------------------------------------------------------------------
Salplex Ltd                    L150,000              Marconi Corporation plc - 90,000                                      60
------------------------------------------------------------------------------------------------------------------------------
Streamvpn Ltd               54,788.80 ord            Marconi Corporation plc - 88,888 ordinary 10p shares                16.2
                                  10p
------------------------------------------------------------------------------------------------------------------------------
The M-O Valve Co             L50,000 ord             Marconi Corporation plc - 99,999 ordinary 50p shares                 100
</TABLE>

                                     - 36 -

<PAGE>

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------------------------
                             Issued Share                    Description And Number of Shares Held                     % Owned
   Name of Company             Capital                  (ordinary L1.00 shares unless otherwise stated)
------------------------------------------------------------------------------------------------------------------------------
<S>                         <C>                      <C>                                                             <C>
Ltd                             50p                  Associated Electrical Industries Holdings Limited- 1
                                                     ordinary 50p share
------------------------------------------------------------------------------------------------------------------------------
The Rotary Engineering         L7,500                Marconi Corporation plc - 7,499                                      100
Company Ltd                                          Associated Electrical Industries Holdings Limited - 1
------------------------------------------------------------------------------------------------------------------------------
Ultramast Ltd               L126 deferred L1         Marconi Corporation plc - 63 deferred L1 shares                        50
                            L133 ordinary L1                                                                          deferred
                                                                                                                     24 total
                                                                                                                      issued
------------------------------------------------------------------------------------------------------------------------------
Woods of Colchester             L200                 Marconi Corporation plc - 196                                        100
Housing Society Ltd                                  Marconi Corporation plc Account MAS - 1
                                                     Marconi Corporation plc Account CGD - 1
                                                     Marconi Corporation plc Account KDS - 1
                                                     Associated Electrical Industries Holdings Limited - 1
------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                     - 37 -

<PAGE>

                                   SCHEDULE 5

                                     PART C

                FORM OF NOTICE OF ASSIGNMENT OF ASSIGNED ACCOUNTS

To:          [Escrow Bank]

From:        Marconi Corporation plc

Copied to:   The Law Debenture Trust Corporation p.l.c. (the "SECURITY TRUSTEE")

                                                          Date: [              ]

Dear Sirs,

DEBENTURE DATED [              ] BETWEEN MARCONI CORPORATION PLC AND OTHERS AND
THE LAW DEBENTURE TRUST CORPORATION P.L.C. (THE "DEBENTURE")

We give you notice that we have assigned and charged to the Security Trustee for
and on behalf of the Secured Creditors all of our right, title and interest in
and to account numbers [              ] (account names [              ]) (the
"ASSIGNED ACCOUNTS") (including any renewal or redesignation thereof) and all
monies standing to the credit of that account from time to time pursuant to the
terms of the Debenture.

We confirm that operation of the Assigned Accounts are subject to an Escrow
Agreement dated [              ] between Marconi Corporation plc and The Law
Debenture Trust Corporation p.l.c. as Security Trustee. We further confirm that
with effect from the date of your receipt of this notice, withdrawals (as far as
you, as the Escrow Bank, are concerned) from any of the Assigned Accounts shall
be governed by the terms of this notice and the Escrow Agreement.

We hereby instruct and authorise you:

(a)      to disclose to the Security Trustee as soon as is reasonably
         practicable any information relating to the Assigned Accounts, which
         you are in possession of as holder of the Assigned Accounts, at any
         time upon their request; and

(b)      not to permit withdrawals from the Assigned Accounts unless you receive
         a release instruction from the Security Trustee (in the form attached
         hereto).

Subject to paragraph (b) above, all rights, interests and benefits whatsoever
accruing to or for the benefit of ourselves arising from the Assigned Accounts
belong to the Security Trustee.

This letter is governed by English law.

                                     - 38 -

<PAGE>

Please accept this notice by signing the enclosed acknowledgement and returning
it to the Security Trustee at Fifth Floor, 100 Wood Street, London EC2V 7EX, for
the attention of Manager Trust Administration.

Yours faithfully
_______________________
MARCONI CORPORATION PLC

                                     - 39 -

<PAGE>

                           FORM OF RELEASE INSTRUCTION

To:   [Escrow Bank]

From: The Law Debenture Trust Corporation p.l.c. (the "SECURITY TRUSTEE")

Copy: Marconi Corporation plc (the "COMPANY")

                                                          Date: [              ]

Dear Sirs

ASSIGNED ACCOUNT NUMBER [     ] (ACCOUNT NAME [     ])

We refer to the Notice of Assignment dated [     ] sent by the Company to you
(the "NOTICE") in connection with certain security arrangements described
therein.

We wish to withdraw [ - ] from the Assigned Account on [     ] to be credited to
[account details].

This release instruction is governed by English law.

Yours faithfully
__________________________________________
for and on behalf of
THE LAW DEBENTURE TRUST CORPORATION P.L.C.
AS SECURITY TRUSTEE

                                     - 40 -

<PAGE>

                     FORM OF ACKNOWLEDGEMENT OF ESCROW BANK

To:   The Law Debenture Trust Corporation p.l.c. (the "SECURITY TRUSTEE") and
      Marconi Corporation plc (the "COMPANY")

                                                            Date: [            ]

Dear Sirs

DEBENTURE DATED [         ] BETWEEN MARCONI CORPORATION PLC AND OTHERS AND THE
LAW DEBENTURE TRUST CORPORATION P.L.C. (THE "DEBENTURE")

We refer to the Assigned Accounts with account numbers [     ] (account names
[     ]) held with us and a notice of assignment from Marconi Corporation plc
dated [     ] in connection with the Debenture (the "NOTICE").

At the request of the Security Trustee and the Company we acknowledge receipt of
the Notice and confirm that:

(d)      we accept the instructions contained in the Notice and agree to comply
         with the Notice;

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

(f)      we have:

         (i)      not claimed or exercised, nor will claim or exercise, any
                  security interest, set off, counter-claim, combination,
                  consolidation or other right in respect of any of the Assigned
                  Accounts; and

         (ii)     waived all rights and claims of any kind that we may have
                  against the Company in respect of the Assigned Accounts;

(g)      we will not amend or vary any rights attaching to the Assigned
         Accounts; and

(h)      we will act only in accordance with the instructions of the Security
         Trustee and we shall send all statements and other notices given by us
         relating to the Assigned Accounts to the Security Trustee.

This letter is governed by English law.

Yours faithfully
____________________
for and on behalf of
[ESCROW BANK]

                                     - 41 -

<PAGE>

                                     PART D

                FORM OF NOTICE OF ASSIGNMENT OF INTRA-GROUP LOAN

To: [                ]

                                                          Date: [              ]

Dear Sirs,

DEBENTURE DATED [              ] BY [              ] (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, 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 English law.

                                     - 42 -

<PAGE>

Please acknowledge receipt of this notice by signing the acknowledgement on the
enclosed copy letter and returning it to us at Fifth Floor, 100 Wood Street,
London EC2V 7EX marked for the attention of Manager Trust Administration.

Yours faithfully,

________________________

THE LAW DEBENTURE TRUST CORPORATION P.L.C.
as attorney for and on behalf
[         ] (the "COMPANY")

                                     - 43 -

<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:

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

(j)      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

(k)      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:

                                     - 44 -

<PAGE>

                                   SCHEDULE 6

                                     PART E

                      FORM OF NOTICE OF CHARGE TO LANDLORDS

To:          [Landlord]

Date:        [       ]

Dear Sirs,

We give you notice that, by a Debenture dated [   ] (the "DEBENTURE") and by a
Mortgage dated [    ] (the "MORTGAGE") 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
England and Wales. Would you acknowledge receipt of this notice by sending the
enclosed acknowledgement to the Security Trustee with a copy to ourselves.

Yours faithfully

[              ]

                                     - 45 -

<PAGE>

                            ACKNOWLEDGEMENT OF CHARGE

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

Date:      [       ]

Dear Sirs

We confirm receipt from [Chargor] (the "COMPANY") of a notice dated [         ]
of a charge upon the terms of a Debenture dated [         ] (the "DEBENTURE")
and a Mortgage dated [         ] (the "MORTGAGE") 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
England and Wales.

Yours faithfully

[Landlord]

                                     - 46 -

<PAGE>

                                   SCHEDULE 6

                                     PART F

                      FORM OF NOTICE OF CHARGE OVER ACCOUNT

To:  [Account Bank]

Dear Sirs,

We hereby give you notice, as attorney for and on behalf of 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:

(l)      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;

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

(n)      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;

(o)      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

(p)      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 English law.

                                     - 47 -

<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 [              ] (the "COMPANY")

                                     - 48 -

<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 [           ] (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 English Law.

Yours faithfully,

___________________
On behalf of [Bank]

                                     - 49 -

<PAGE>

                                     PART G

                  FORM OF NOTICE OF CHARGE OVER MONETARY CLAIMS

To:    [               ]

                                                          Date: [              ]

Dear Sirs,

DEBENTURE DATED [            ] BY [              ] (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:

5.       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];

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

7.       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;

8.       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

9.       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.

                                     - 50 -

<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 English law.

Please acknowledge receipt of this notice by signing the acknowledgement on the
enclosed copy letter and returning it to us at Fifth Floor, 100 Wood Street,
London EC2V 7EX marked for the attention of Manager Trust Administration.

Yours faithfully,

______________________

by

THE LAW DEBENTURE TRUST CORPORATION P.L.C.
as attorney for and on behalf of
[         ] (the "COMPANY")

                                     - 51 -

<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:

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

(r)      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:

                                     - 52 -

<PAGE>

                                   SCHEDULE 7

                             FORM OF LEGAL MORTGAGE

                                DATED [         ]

                                   [        ]

                                       AND

                   THE LAW DEBENTURE TRUST CORPORATION P.L.C.

--------------------------------------------------------------------------------

                                    MORTGAGE

--------------------------------------------------------------------------------

To: H.M. Chief Land Registrar. Note: This deed contains (in Clause 3 (Request to
H.M. Chief Land Registrar)) an application to enter a restriction on the
Proprietorship Register) and (in Clause 4 (Further Advances)) an application to
enter a notice on the Charges Register

                                     - 53 -

<PAGE>

THIS DEED is dated [         ] between:

(1)      [        ] registered in England and Wales with company number [      ]
         (the "COMPANY"); and

(2)      THE LAW DEBENTURE TRUST CORPORATION P.L.C. of Fifth Floor, 100 Wood
         Street, London EC2V 7EX as security trustee (the "SECURITY TRUSTEE").

BACKGROUND:

It is intended that this document takes effect as a deed notwithstanding the
fact that a party may only execute this document under hand.

IT IS AGREED as follows:

10.      DEFINITIONS

         In this Deed:

        "MORTGAGED PROPERTY" means:

         (a)      the property specified in Schedule 1 (Details of Mortgaged
                  Property); and

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

         and includes all Related Rights.

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

         (a)      the proceeds of sale of 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.

         "SECURED OBLIGATIONS" means all obligations which the Company may at
         any time have to the Security Trustee (whether for its own account or
         as trustee for the Secured Creditors) or any of the other secured
         creditors including any liability in respect of further advances made,
         whether actual or contingent, present or future (and whether incurred
         solely or jointly and whether as principal or as surety or in some
         other capacity).

11.      FIXED SECURITY

         The Company hereby charges with full title guarantee in favour of the
         Security Trustee with the payment and discharge of the Secured
         Obligations, by way of legal mortgage all the Company's right, title
         and interest from time to time in the Mortgaged Property.

                                     - 54 -

<PAGE>

12.      REQUEST TO H.M. CHIEF LAND REGISTRAR

         The Company hereby applies to H.M. Chief Land Registrar to enter the
         following restriction in the Proprietorship register of any property
         which is, or is required to be, registered forming part of the
         Mortgaged Property:

                  "Except under an Order of the Registrar, no transfer,
                  disposition, dealing, charge or mortgage by the proprietor of
                  the land or any transfer made in the exercise of the power of
                  sale possessed by the holder of any subsequent charge is to be
                  registered or noted without the consent of the proprietor for
                  the time being of Charge No. [-]".

13.      FURTHER ADVANCES

13.1     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 Mortgage as if set out in this Mortgage.

13.2     The Company hereby applies to H.M. Chief Land Registrar to enter a note
         of the obligation to make further advances on the Charges register of
         any registered land forming part of the Mortgaged Property.

14.      RELEASE OF SECURITY

14.1     REDEMPTION OF SECURITY

         Upon the Security Trustee receiving confirmation from the Secured
         Creditors that the Secured Obligations have been discharged in full and
         none of the Secured Creditors being under any further actual or
         contingent obligation to make advances or provide other financial
         accommodation to the Company or any other person under any agreement
         between the Security Trustee and the Company, the Security Trustee
         shall, at the request and cost of the Company, release and cancel the
         security constituted by this Mortgage and procure the reassignment to
         the Company of the property and assets assigned to the Security Trustee
         pursuant to this Mortgage, in each case subject to Clause 5.2
         (Avoidance of Payments) and without recourse to, or any representation
         or warranty by, the Security Trustee or any of its nominees.

14.2     AVOIDANCE OF PAYMENTS

         If the Security Trustee (on the basis of legal advice received by it
         for this purpose) considers that an amount paid to the Security Trustee
         or any Secured Creditor for application in or towards repayment of the
         Secured Obligations is (having regard to circumstances then existing)
         capable of being avoided or otherwise set aside on the liquidation or
         administration of any Company or otherwise, then such amount shall not
         be considered to have been irrevocably paid and such Secured
         Obligations shall not be considered to have been discharged in full for
         the purposes of this Debenture or any Mortgage PROVIDED THAT the
         Security Trustee shall be entitled but not obliged, independently and
         in the absence of a request by a Secured Creditor, to investigate,
         enquire or consider whether a payment can be avoided or set aside on
         the liquidation or administration of a Company or otherwise.

15.      THIRD PARTY RIGHTS

         A person who is not a party to this Deed shall have no rights under the
         Contract (Rights of Third Parties) Act 1999 to enforce any term of this
         Deed.

                                     - 55 -

<PAGE>

16.      GOVERNING LAW

         This Deed is governed by English law.

17.      COUNTERPARTS

         This Deed 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 Deed. Any
         party may enter into this Deed by signing any such counterpart.

THIS DEED has been entered into as a deed on the date stated at the beginning of
this Deed.

                                     - 56 -

<PAGE>

                                   SCHEDULE 1

                          DETAILS OF MORTGAGED PROPERTY

<TABLE>
<CAPTION>
County and District/
  London Borough                      Description of Property            Title Number
<S>                                   <C>                                <C>
   [         ]                              [         ]                   [         ]
</TABLE>

[Execution page]

                                     - 57 -

<PAGE>

                                 EXECUTION PAGES

THE COMPANIES

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
ASSOCIATED ELECTRICAL               )
INDUSTRIES LIMITED                  )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

EXECUTED as a DEED                  )
By W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
ELLIOTT-AUTOMATION                  )
HOLDINGS LIMITED                    )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

                                     - 58 -

<PAGE>

EXECUTED as a DEED                  )
by T.C.R. SHEPHERD                  )        T.C.R. SHEPHERD
acting as attorney-in-fact          )
for and on behalf of                )
ENGLISH ELECTRIC                    )
COMPANY LIMITED                     )
in the presence of:                 )

Signature of witness:      S. KNIGHT

Name of witness:           Stephen Knight

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

EXECUTED as a DEED                  )
By T.C.R. SHEPHERD                  )        T.C.R. SHEPHERD
acting as attorney-in-fact          )
for and on behalf of                )
GPT SPECIAL PROJECTS                )
MANAGEMENT LIMITED                  )
in the presence of:                 )

Signature of witness:      S. KNIGHT

Name of witness:           Stephen Knight

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

                                     - 59 -

<PAGE>

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
HIGHROSE LIMITED                    )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

EXECUTED as a DEED                  )
By W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI (BRUTON                     )
STREET) LIMITED                     )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

                                     - 60 -

<PAGE>

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI (DGP1) LIMITED              )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI (DGP2) LIMITED              )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

                                     - 61 -

<PAGE>

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI (ELLIOTT                    )
AUTOMATION) LIMITED                 )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI (NCP) LIMITED               )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

                                     - 62 -

<PAGE>

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI AEROSPACE                   )
UNLIMITED                           )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI BONDING LIMITED             )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

                                     - 63 -

<PAGE>

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI COMMUNICATIONS              )
CHINA LIMITED                       )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

EXECUTED as a DEED                  )
By W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI COMMUNICATIONS              )
HOLDINGS LIMITED                    )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

                                     - 64 -

<PAGE>

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI COMMUNICATIONS              )
INTERNATIONAL HOLDINGS              )
LIMITED                             )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI COMMUNICATIONS              )
INTERNATIONAL                       )
INVESTMENTS LIMITED                 )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

                                     - 65 -

<PAGE>

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI COMMUNICATIONS              )
INTERNATIONAL LIMITED               )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI COMMUNICATIONS              )
INVESTMENTS LIMITED                 )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

                                     - 66 -

<PAGE>

EXECUTED as a DEED                  )
By W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI COMMUNICATIONS              )
LIMITED                             )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

EXECUTED as a DEED                  )
by MARY SKELLY                      )        M. SKELLY
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI CORPORATION PLC             )
in the presence of:                 )

Signature of witness:      S. KNIGHT

Name of witness:           Stephen Knight

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

                                     - 67 -

<PAGE>

EXECUTED as a DEED                  )
by W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI OPTICAL                     )
COMPONENTS LIMITED                  )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

EXECUTED as a DEED                  )
By W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MARCONI UK INTELLECTUAL             )
PROPERTY LIMITED                    )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

                                     - 68 -

<PAGE>

EXECUTED as a DEED                  )
By W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
METAPATH SOFTWARE                   )
INTERNATIONAL LIMITED               )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           SOPHY LEVY

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

EXECUTED as a DEED                  )
By W. JOHNSON                       )        W. JOHNSON
acting as attorney-in-fact          )
for and on behalf of                )
MOBILE SYSTEMS                      )
INTERNATIONAL                       )
HOLDINGS LIMITED                    )
in the presence of:                 )

Signature of witness:      S LEVY

Name of witness:           Sophy Levy

Address:                   Allen and Overy, One New Change, London EC4M 9QQ

Occupation:                TRAINEE SOLICITOR

                                     - 69 -

<PAGE>

The Security Trustee

THE LAW DEBENTURE TRUST CORPORATION P.L.C.

By:           R.D. RANCE        J. M. JEBB

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

                                     - 70 -