<PAGE>

                                                                  Exhibit 4.1

                                                                  Conformed copy

                               Dated 11 March 2001

                            Williams Security Limited

                                     - and -

                           Baltimore Technologies plc

                                     - and -

                                    Chubb plc

                                    Agreement

                                 - relating to -

           The sale and purchase of the entire issued share capital of
                       Chubb Information Security limited

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                                    Contents

Clause
                                                                         Page No
                                                                         -------
1.    Interpretation                                                         1

2.    Sale and purchase of the Shares                                        4

3.    Consideration                                                          4

4.    Completion                                                             4

5.    Pre-Completion matters                                                 6

6.    Intellectual Property                                                  8

7.    Retention                                                              8

8.    Warranties                                                             9

9.    Limitation on claims                                                   9

10.   Employees and Pensions                                                11

10A   Licence to store and maintain SMC Rack                                12

10B   15 Wheeler Gate, Nottingham                                           13

10D   VAT                                                                   13

11.   Confidentiality and announcements                                     15

12.   Further assurance and availability of information                     15

13.   Interest                                                              15

14.   Continuing obligations and assignment                                 15

15.   Costs                                                                 15

16.   Notices                                                               15

17.   Severability                                                          16

18.   Entire agreement and variation                                        16

19.   General provisions                                                    16

20.   Guarantee                                                             17

21.   Governing law and jurisdiction                                        17

Schedule I                                                                  19

      The Company                                                           19

Schedule II                                                                 20

      The Properties                                                        20

Schedule III                                                                21

      Employees                                                             21

Schedule IV                                                                 22

      Warranties                                                            22

Schedule V                                                                  27

      Form of deed of covenant                                              27

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                                     - ii -

Agreed form documents:

Form of resignation of directors/secretary 4.3(e)
Power of attorney in relation to the Shares 4.3(h)
Trade Mark Licence Agreement 4.3(i)
Secondment Agreement 4.3(k)

<PAGE>

This Agreement is made the 11th day of March 2001

Between:

(1)  Williams Security Limited, a company registered in England and Wales under
     number 2985115 whose registered office is at Pentagon House, Sir Frank
     Whittle Road, Derby DE21 4XA, United Kingdom, facsimile number: 01332
     387066 (the "Seller");

(2)  Baltimore Technologies plc a company registered in England and Wales under
     number 2643615 whose registered office is at The Square, Basing View,
     Basingstoke, Hampshire RG21 4EG, United Kingdom, facsimile number: 01256
     812 901 (the "Purchaser"); and

(3)  Chubb plc a company registered in England and Wales under number 4034666
     whose registered office is at Pentagon House, Sir Frank Whittle Road, Derby
     DE21 4XA, United Kingdom, facsimile number: 01332 387066 (the "Guarantor").

Recitals:

(A)  Chubb Information Security Limited is a company registered in England and
     Wales under number 3904130 whose registered office is at Pentagon House,
     Sir Frank Whittle Road, Derby DE21 4XA, United Kingdom (the "Company"). At
     the date hereof the Company has an authorised share capital of
     (pound)10,000,000 divided into 10,000,000 ordinary shares of (pound)1 each,
     of whicH 6,730,000 shares have been allotted and issued and are fully paid.
     Further particulars of the Company are set out in Schedule I.

(B)  The Seller is the beneficial owner of the Shares.

(C)  The Seller has agreed to sell and the Purchaser has agreed to purchase the
     Shares on and subject to the terms of this Agreement.

It is agreed:

1.   Interpretation

1.1  In this Agreement (including its Recitals and Schedules), the following
     words and expressions have the meanings respectively set opposite them.

     "Accounts" means the management accounts of the Company as at and for the
     period ended on the Balance Sheet Date, initialled for the purpose of
     identification by or on behalf of the parties;

     "Balance Sheet Date" means 23 February 2001;

     "Business" means all of the business of the Company and all of the business
     of the Seller or any member of the Seller's Group consisting of the
     provision of the services set out in Schedule 1 of the Trade Mark Licence
     Agreement;

     "Business Day" means any day (except any Saturday or Sunday or a public
     holiday) on which banks in the City of London are open for business;

     "Business Plan" means the Chubb Information Security Limited Business Plan
     set out at Volume 1, document 18 on the Data Room Index (as defined in
     clause 8 of this Agreement);

     "Chubb Marks" means any trade mark or name which includes the word "Chubb"
     or the "C" logo;

     "Company" has the meaning given in Recital (A);

     "Completion" means completion of the sale and purchase of the Shares
     pursuant to this Agreement in accordance with its terms;

     "Completion Date" means 27 April 2001;

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                                      - 2 -

     "Demised Premises" means the premises described in clause 1(d) of the
     Lease;

     "Deed of Covenant" means a deed in the form set out in Schedule V;

     "Disclosure Letter" means the letter of the same date as this Agreement
     from the Seller to the Purchaser referred to in clause 8.2 and which
     includes, for the avoidance of doubt, all the documents delivered to the
     Purchaser with that letter;

     "Employees" means the persons listed in Schedule III;

     "Employment Statutes" means all legislation (whether of the United Kingdom,
     any part thereof, Canada or elsewhere), including without limitation the
     Treaty establishing the European Community and any directives made under
     the authority of that Treaty, relating in any way to the employment of
     employees or other workers (whether individually or collectively) or the
     terms on which they are employed and including, for the avoidance of doubt,
     any such legislation relating to health and safety;

     "Environment" means air (including, without limitation, air within
     buildings and natural or man made structures above or below ground), water
     and land;

     "Environmental Laws" means all applicable laws (including common law)
     whether of the United Kingdom or any part thereof, relating to pollution or
     protection of the Environment or human health and safety and in force and
     binding upon the Company at the date of this Agreement, including laws
     relating to emissions, seepages, spillages, discharges, escapes, releases
     or threatened escapes or releases of pollutants, contaminants, chemicals or
     toxic or hazardous substances, wastes, materials or noise into the
     Environment or otherwise relating to the manufacture, processing,
     distribution, use, keeping, treatment, disposal, deposit, storage,
     transport or handling of the same;

     "ICTA 1988" means the Income and Corporation Taxes Act 1988;

     "Intellectual Property" means patents (including supplementary protection
     certificates), trade marks, service marks, registered designs, utility
     models, design rights, topography rights, copyrights, inventions, trade
     secrets and other confidential information, know-how, business or trade
     names and all other intellectual property and neighbouring rights and
     rights of a similar or corresponding character in any part of the world
     (whether or not the same are registered or capable of registration) and all
     applications and rights to apply for or for the protection of any of the
     foregoing;

     "Inter-Company Debt" means inter-company debt owed by the Company to any
     company in the Seller's Group;

     "Lease" means the lease of the Demised Premises detailed in Schedule II
     between Southern Water Services Limited and Security Monitoring Centres
     Limited dated 24 December 1997 as amended by the Licence to Assign and Deed
     of Variation between Southern Water Services Limited, Security Monitoring
     Centres Limited and the Company dated 20 February 2001;

     "Licence Period" shall mean the period from the date of this Agreement
     until the expiry of the Lease (howsoever determined);

     "Planning Acts" means the Town and Country Planning Act 1990, the Planning
     (Listed Buildings and Conservation Areas) Act 1990, the Planning (Hazardous
     Substances) Act 1990, the Planning (Consequential Provisions) Act 1990 and
     the Planning and Compensation Act 1991;

     "Property" means the Company's leasehold interest in the Demised Premises
     in terms of the Lease, which interest is detailed in Schedule II;

     "Purchaser's Solicitors" Lovells of 65 Holborn Viaduct, London EC1A 2DY;

     "Recharged Expenditure" means an amount of up to (pound)1,850,000
     (exclusive of VAT) represeNTING costs incurred by the Seller's Group in
     connection with the Business which, the Purchaser acknowledges, may be
     recharged to the Company prior to Completion

<PAGE>

                                      - 3 -

     (provided that any amounts charged by the New Invoices as defined in clause
     10D.6 shall not be Recharged Expenditure);

     "Recharged Inter-Company Debt" means an amount of up to (pound)1.85 million
     (exclusive of VAT) WHICH is the inter-company debt owed by the Company to
     companies within the Seller's Group as a result of the recharge to the
     Company of the Recharged Expenditure provided that amounts due in respect
     of VAT shall not be Recharged Inter-Company Debt (thus meaning that the
     maximum amount of Recharged Inter-Company Debt is (pound)1.85 million);

     "Retention" means (pound)300,000, to be retained from the consideration and
     dealt with in accorDANCE with the provisions of clause 7;

     "Retention Account" means the bank account referred to in clause 7.1;

     "Seller's Group" means the Guarantor and its subsidiaries from time to
     time;

     "Seller's Pension Schemes" means the Chubb Security Pension Fund currently
     constituted under a trust deed dated 15 May 1980 (as amended) and the Chubb
     Pension Plan currently constituted under a trust deed dated 24 April 1996
     (as amended);

     "Seller's Solicitors" Slaughter and May of 35 Basinghall Street, London
     EC2V 5DB;

     "Shares" means the entire issued share capital of the Company, being
     6,730,000 ordinary shares of (pound)1 each;

     "SMC Rack" shall mean the Equipment Racks and Sainsburys Receiving
     Equipment owned or used by the Seller's Group and all or any part of such
     equipment and such other equipment as the parties acting reasonably may
     agree;

     "Stock Exchange" means London Stock Exchange plc;

     "Trade Mark Licence Agreement" means the agreement in the agreed terms
     between Chubb International Holdings Limited as licensor and the Company as
     licensee; and

     "Warranties" means the warranties set out in Schedule IV.

1.2  In this Agreement, unless the context otherwise requires:

     (a)  references to this Agreement or any other document include this
          Agreement or such other document as varied, modified or supplemented
          in any manner from time to time;

     (b)  references to any party shall, where relevant, be deemed to be
          references to or to include, as appropriate, their respective
          permitted successors, assigns or transferees;

     (c)  references to recitals, clauses and schedules and sub-divisions of
          them are references to the recitals and clauses of, and schedules to,
          this Agreement and sub-divisions of them respectively;

     (d)  references to any enactment include references to such enactment as
          re-enacted, amended or extended on or before the date of this
          Agreement and any subordinate legislation made from time to time under
          it;

     (e)  references to a "person" include any individual, company, corporation,
          firm, partnership, joint venture, association, organisation,
          institution, trust or agency, whether or not having a separate legal
          personality;

     (f)  references to the one gender include all genders, and references to
          the singular include the plural and vice versa;

     (g)  any reference to indemnifying any person against any circumstance
          includes indemnifying and holding that person harmless from all
          actions, claims, demands

<PAGE>

                                      - 4 -

          and proceedings of any nature from time to time made against that
          person and all losses, damages, payments, awards, costs or expenses
          made, suffered or incurred by that person as a consequence of, or
          which would not have arisen but for, that circumstance;

     (h)  headings are inserted for convenience only and shall be ignored in
          construing this Agreement; and

     (i)  the words "company", "subsidiary", "subsidiary undertaking" and
          "holding company" have the meanings given to them by the Companies Act
          1985 as amended by the Companies Act 1989.

1.3  The Recitals and Schedules to this Agreement form part of it.

1.4  Any reference in this Agreement to a document being "in the agreed terms"
     is to a document in the terms agreed between the parties and for
     identification purposes only signed or initialled by them or on their
     behalf on or before the date of this Agreement.

2.   Sale and purchase of the Shares

2.1  On and subject to the terms of this Agreement, the Seller shall sell with
     full title guarantee the Shares and the Purchaser shall purchase the Shares
     on and with effect from Completion, in each case free from all charges,
     liens, equities, encumbrances, claims or restrictions whatsoever and
     together with all rights which are now, or at any time hereafter may
     become, attached to them (including without limitation the right to receive
     all dividends and distributions declared, made or paid on or after
     Completion).

3.   Consideration

     The total consideration payable by the Purchaser to the Seller shall,
     subject to adjustment in accordance with this Agreement, be the sum of
     (pound)5,150,000 less an amount equal to the RechARGED Inter-Company Debt.
     The total consideration payable by the Purchaser shall be satisfied by:

     (a)  the payment to the Seller, on Completion, of the sum of
          (pound)4,850,000 less an amount equal to THE Recharged Inter-Company
          Debt in cash in accordance with clause 4; and

     (b)  the payment of the Retention in accordance with clause 7.

4.   Completion

4.1  Completion shall take place at the offices of the Purchaser's Solicitors on
     the Completion Date or at such other place and/or on such earlier date as
     may be agreed between the parties.

4.2  On or before Completion the Seller shall procure and the Purchaser shall
     permit that:

     (a)  all loans and debts due to the Company from, and all loans and debts
          due from the Company to, the Seller and every other company in the
          Seller's Group (other than the Recharged Inter-Company Debt and any
          amounts due in respect of VAT as referred to in clause 10D.6 and
          10D.7) shall be repaid or paid in full;

     (b)  all loans due to the Company from, and all loans due from the Company
          to, directors or employees of the Company shall be repaid in full;

     (c)  all salaries, directors' fees, expenses and bonuses (if any) of all
          directors and employees of the Company, save for any amounts
          specifically detailed in the Disclosure Letter, shall be paid up to
          the Completion Date including any pro-rated amounts for the period up
          to the Completion Date.

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                                      - 5 -

4.3  On Completion the Seller shall cause to be delivered to the Purchaser:

     (a)  a duly executed transfer of the Shares by the registered holder
          thereof in favour of the Purchaser (or as it may direct) together with
          the share certificate relating to such shares;

     (b)  such other documents (including any power of attorney under which any
          document required to be delivered under this clause has been executed
          and any waivers or consents) as the Purchaser may require to enable
          the Purchaser or its nominees to be registered as holder of the
          Shares;

     (c)  the common seal, certificate of incorporation, certificates of
          incorporation on change of name and statutory books of the Company;

     (d)  the Deed of Covenant duly executed by the Guarantor;

     (e)  written letters of resignation (with effect from the end of the
          relevant board meeting referred to in clause 4.4) from all directors
          and the secretary of the Company (except for Andrew Michael Burton),
          resigning from their respective offices and employments with the
          Company;

     (f)  an unqualified letter of resignation from the auditors of the Company
          complying in all respects with the requirements of sections 392 and
          394 Companies Act 1985, accompanied by a written confirmation that
          such auditors have no claims for unpaid fees or expenses.

     (g)  the Lease;

     (h)  an irrevocable power of attorney in the agreed terms executed by the
          holder of the Shares in favour of the Purchaser appointing the
          Purchaser to be its or his lawful attorney in respect of the Shares
          with effect from Completion;

     (i)  the Trade Mark Licence Agreement duly executed by the Company as
          licensee and Chubb International Holdings Limited as licensor;

     (j)  duly executed employment agreements, in the agreed terms, between the
          Employees and the Company;

     (k)  the duly executed secondment agreement in the agreed terms;

     (l)  certified minutes of the meetings of the board of directors of the
          Seller, the Guarantor and Chubb International Holdings Limited
          approving the transactions contained in this Agreement to which they
          are party and the documents referred to herein and authorising the
          execution thereof by the Seller, the Guarantor and Chubb International
          Holdings Limited (as the case may be); and

     (m)  a VAT invoice for the Recharged Expenditure addressed to the Company.

4.4  On Completion the Seller shall cause a Board Meeting of the Company to be
     duly convened and held (or a written resolution of the board to be passed)
     at which:

     (a)  the said transfer of the Shares shall be approved for registration
          (subject only to the transfer being duly stamped at the cost of the
          Purchaser);

     (b)  Paul Sanders and Simon Enoch shall be appointed directors, and Simon
          Enoch shall be appointed secretary, of the Company (within the maximum
          number, if any, permitted under its Articles of Association);

     (c)  the Deed of Covenant, the Trade Mark Licence Agreement and the
          secondment agreement referred to in clause 4.3(d), (i) and (k), shall
          be approved by the Company;

     (d)  the registered office of the Company shall be changed to Building
          1310, Arlington Business Park, Theale, Berkshire RG7 4SA, United
          Kingdom; and

<PAGE>

                                      - 6 -

     (e)  Messrs KPMG Audit plc shall be appointed auditors to the Company.

4.5  On Completion the Purchaser shall, following compliance by the Seller with
     the foregoing provisions:

     (a)  in consideration for the Shares:

          (i)  pay the sum of (pound)4,850,000 less an amount equal to the
               Recharged Inter-Company Debt intO THE account of Chubb Group
               Limited at Barclays Bank PLC, Sort Code 20 25 85, account number
               70923540;

          (ii) pay into the Retention Account (in accordance with the provisions
               of clause 7) the sum of (pound)300,000;

     (b)  procure the repayment by the Company of the Recharged Inter-Company
          Debt to the relevant members of the Seller's Group; and

     (c)  deliver to the Seller's Solicitors the Deed of Covenant, the Trade
          Mark Licence Agreement, secondment agreement and certified minutes of
          the Purchaser approving the transactions contained in this Agreement
          to which it is party and the documents referred to herein and
          authorising the execution thereof by the Purchaser.

4.6  As soon as is practicable following Completion the Seller shall procure the
     release of the Company from any guarantee or other obligation of any nature
     undertaken by it securing or otherwise in respect of the obligations of the
     Seller and pending such release shall indemnify each of the Purchaser and
     the Company against any liability, loss, claim or expense whatsoever or
     other obligation to the extent that such liability, loss, claim or expenses
     arises or is suffered on or after the date hereof.

5.   Pre-Completion matters

5.1  Subject to clause 5.3, pending Completion the Seller shall use its
     reasonable endeavours to procure that, save with the prior written consent
     of the Purchaser (such consent not to be unreasonably withheld or delayed):

     (a)  the Business will be carried on in the ordinary and usual course and
          that the Company will comply, in all material respects, with all
          applicable laws and will maintain all material licences, consents and
          authorisations of any nature whatsoever (public or private) which are
          necessary to carry on the business of the Company from time to time;

     (b)  the Purchaser will be kept informed of all material matters relating
          to the business, assets and affairs of the Company;

     (c)  the Demised Premises are maintained in a state of repair and condition
          as is consistent with the provisions of the Lease;

     (d)  if so requested by the Purchaser, the Company will enforce, or procure
          to be enforced, to their full extent, the obligations of employees or
          directors of the Company (whether under their employment contracts or
          otherwise);

     (e)  the Company will keep proper accounting records and in them make true
          and complete entries of all dealings and transactions in relation to
          its businesses;

     (f)  the Purchaser and its representatives will be afforded reasonable
          access to the Property, all employees, directors, officers and
          advisers of the Company and all documents, books and records held or
          maintained by the Company or held or maintained by the Seller or any
          of its advisers relating thereto; and

     (g)  the Company will remain at its present location at Chubb House,
          Staines Road West, Sunbury-upon-Thames, Middlesex TW16 7AR, United
          Kingdom.

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                                      - 7 -

5.2  Subject to clause 5.3, without prejudice to the provisions of clause 5.1,
     pending Completion the Seller shall use its reasonable endeavours to
     procure that none of the following matters will occur or be undertaken
     without the prior written consent of the Purchaser (such consent not to be
     unreasonably withheld or delayed):

     (a)  the modification of any of the rights attached to any shares in the
          Company or the creation or issue of any shares or the grant or
          agreement to grant any option over any shares or uncalled capital of
          the Company or the issue of any obligations convertible into shares;

     (b)  the capitalisation or repayment of any amount standing to the credit
          of any reserve of the Company or the redemption or purchase of any
          shares or any other reorganisation of the share capital of the
          Company;

     (c)  the admission of any person (howsoever occurring) as a member of the
          Company by the transfer or approval of the transfer of the Shares;

     (d)  the sale or disposal of, or the grant or termination of any rights in
          respect of, any material part of the undertaking or the assets of the
          Company;

     (e)  the declaration, payment or other making by the Company of any
          dividend or other distribution;

     (f)  the passing of any resolution by the members of the Company, including
          any alteration to the Memorandum or Articles of Association of the
          Company;

     (g)  the giving by the Company of any guarantee or indemnity under which
          the Company's potential liability, whether as principal or surety,
          exceeds (pound)50,000;

     (h)  the making of any capital commitment by the Company in excess
          of (pound)100,000 or of capiTAL commitments of any amount which total
          in aggregate (pound)100,000; (i) the acquisition by the Company of any
          shares of any other company or the participation by the Company in any
          partnership, consortium, association or joint venture;

     (j)  the borrowing of any money or acceptance of any financial facility by
          the Company or the making or granting of any loan or any financial
          facility in each case where the amount involved exceeds (pound)50,000;

     (k)  the creation or issue or allowing to come into being of any mortgage,
          charge or other security interest upon or over any part of the
          property of assets or uncalled capital of the Company or the creation
          or issue of any debenture or debenture stock or the obtaining of any
          advance or credit in any form, other than normal trade credit;

     (l)  the employment or dismissal or any material change in the remuneration
          or terms of employment of any director or employee of the Company;

     (m)  the entry into, termination, material amendment or material variation
          of any contract, transaction or arrangement by the Company to which it
          is or would be a party including, without limitation, all material
          arrangements for which material contracts in draft form, heads of
          terms, or other pre-contractual documentation or correspondence
          exists; or

     (n)  the commencement of any litigation by the Company.

5.3  Notwithstanding the provisions of clauses 5.1 and 5.2, the Purchaser
     acknowledges and agrees that prior to Completion the Seller may procure
     that the Recharged Expenditure is recharged to the Company, and such action
     shall not constitute a breach of this Agreement or give rise to any claim
     by the Purchaser under this Agreement whatsoever.

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                                      - 8 -

6.   Intellectual Property

6.1  In the event that the Seller discovers that the Company owns any
     Intellectual Property which has, in the eighteen months prior to
     Completion, been used exclusively by a member of the Seller's Group other
     than in connection with the Business or any trade mark application or
     registration for any of the Chubb Marks, the Purchaser agrees to procure
     that such Intellectual Property or such application or registration is
     transferred to the Seller or a company nominated by the Seller for nominal
     consideration.

6.2  In the event that the Purchaser discovers that the Seller or a member of
     the Seller's Group owns any Intellectual Property (except for the Chubb
     Marks) which has, in the eighteen months prior to Completion, been used in
     the Business exclusively by the Company the Seller agrees to procure that
     such Intellectual Property is transferred to the Company for nominal
     consideration.

6.3  The Purchaser shall, with effect from Completion, procure the grant to the
     Seller of a non-exclusive, perpetual, worldwide, assignable, irrevocable,
     royalty-free licence (with the right to sub-licence) to use any
     Intellectual Property owned by the Company which has been used (but not
     exclusively) in the twelve months prior to Completion by a member of the
     Seller's Group.

6.4  The Seller shall, with effect from Completion, procure the grant to the
     Company of a non-exclusive, perpetual, worldwide, assignable, irrevocable,
     royalty-free licence (with the right to sub-licence) to use any
     Intellectual Property (except for the Chubb Marks) owned by a member of the
     Seller's Group which has been used (but not exclusively) in the twelve
     months prior to Completion in the Business.

7.   Retention

7.1  The Retention shall be paid into a designated interest-bearing account with
     National Westminster Bank PLC, in the joint names of the Seller's
     Solicitors and the Purchaser's Solicitors (the "Retention Account") on
     Completion and the Retention (together with interest accrued thereon) shall
     be applied in accordance with the provisions of this clause. The
     instructions given to National Westminster Bank PLC on the setting up of
     the Retention Account shall include an instruction that no sums may be
     released from the Retention Account at any time without the authority of
     the Purchaser's Solicitors and the Seller's Solicitors.

7.2  If the Purchaser has not notified the Seller of any claim under this
     Agreement, together with an estimate of the maximum aggregate amount of
     such claim, on or before 30 September 2001, the parties shall procure that
     the Retention (together with accrued interest thereon) shall be released in
     full to the Seller on the Business Day next following that date.

7.3  If the Purchaser has notified the Seller of a claim or claims under this
     Agreement, together with an estimate of the maximum aggregate amount of
     such claim, on or before 30 September 2001, the parties shall procure that
     the amount by which the Retention exceeds the estimated maximum aggregate
     amount of such claim(s) shall be paid out of the Retention to the Seller on
     the first Business Day after 30 September 2001.

7.4  If any such claim(s) are not admitted by the Seller, the Retention (or the
     balance remaining after any interim distribution made under clause 7.3 and
     all interest accrued thereon shall be held in the Retention Account until
     such claim(s) are finally settled or otherwise determined.

7.5  Upon the final settlement or determination of such claim(s), the parties
     shall procure that the Retention (or the balance thereof) and all interest
     accrued thereon shall be forthwith applied in or towards the discharge of
     the amount(s) agreed or determined to be payable to the Purchaser in
     respect of such claim(s) and the residue (if any) including any interest
     remaining after the discharge of such claim(s) shall be released to the
     Seller.

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                                      - 9 -

7.6  The Seller and the Purchaser shall promptly give to the Seller's Solicitors
     and the Purchaser's Solicitors respectively all such written instructions
     as shall be necessary to give effect to the provisions of this clause.

7.7  All costs in connection with the Retention Account shall be borne by the
     Purchaser.

8.   Warranties

8.1  The Seller hereby warrants to the Purchaser as at the date hereof in the
     terms of the Warranties.

8.2  The Warranties are given subject to any fact, matter or circumstance
     disclosed in the Disclosure Letter or in the documents, whether in
     electronic form or otherwise, in the data room (which documents are
     comprised in a bundle initialled for the purpose of identification on
     behalf of the Purchaser and the Seller and listed in the Data Room Index
     which forms Schedule Two to the Disclosure Letter (the "Data Room Index"))
     or in the additional documents included as Schedule Three to the Disclosure
     Letter.

8.3  Each of the Warranties set out in each paragraph and each paragraph of
     Schedule IV shall be separate and independent and shall not (unless stated
     otherwise) be limited by reference to any other paragraph or anything in
     this Agreement or the Schedules.

8.4  Where any statement set out in Schedule IV is expressed to be given or made
     to the best of the Seller's knowledge or is qualified by reference to the
     Seller's awareness or is qualified in some other manner having
     substantially the same effect, such statement shall mean the actual
     knowledge of Roy Brown (Divisional Finance Director of the Parent), having
     made reasonable enquiries of Andrew Burton (Chief Executive Officer of the
     Company) and Ian Stephens (Finance Director of the Company)).

8.5  The Seller agrees with the Purchaser for itself and as trustee for the
     Company and their respective officers and employees that (except in the
     case of fraud) it will not exercise any of its rights, remedies or claims
     which it has or may have in respect of any misrepresentation in or
     omissions from any information or advice supplied or given by the Company
     or its officers, employees or agents and on which the Seller has relied in
     giving the Warranties, preparing the Disclosure Letter and/or entering into
     this Agreement and/or the documents referred to herein.

9.   Limitation on claims

9.1  (a)  Notwithstanding anything in this Agreement to the contrary, the
          provisions of this clause 9 shall operate to limit the liability of
          the Seller in respect of any claim by the Purchaser for any breach of
          or inaccuracy in the Warranties.

     (b)  The Seller shall have no liability in respect of any breach of any of
          the Warranties unless the Purchaser has served on the Seller a written
          notice on or before 30 September 2001 giving full details of the claim
          including the Purchaser's best estimate of the amount of the Seller's
          liability in respect thereof.

     (c)  The liability of the Seller in respect of any claim by the Purchaser
          for any breach of, or inaccuracy in, the Warranties shall absolutely
          determine (if such claim has not been previously satisfied, settled or
          withdrawn) if legal proceedings in respect of such claim shall not
          have been commenced within six months of the service of such notice
          and for this purpose proceedings shall not be deemed to have been
          commenced unless they shall have been properly issued and validly
          served upon the Seller.

9.2  No claim shall be made in respect of any breach of any of the Warranties or
     indemnities in this Agreement (each a "Warranty Claim"):

     (a)  where the liability for any individual claim (or what would be such
          liability apart from this paragraph) is less than (pound)25,000; and

<PAGE>

                                     - 10 -

     (b)  unless the aggregate amount of all such claims in excess of
          (pound)25,000 exceeds (pound)100,000 PROVIDED that if such aggregate
          amount does exceed (pound)100,000, the Seller's liability shaLL BE
          limited to the amount by which such aggregate amount exceeds
          (pound)100,000.

9.3  The total aggregate amount of the Seller's liability in respect of any
     Warranty Claim or Claims, or otherwise under or in connection with this
     Agreement shall be (in the absence of fraud) limited to and shall in no
     event exceed (pound)300,000.

9.4  If, in respect of any matter which would give rise to a Warranty Claim the
     Purchaser or a member of the Purchaser's group (including the Company) (the
     "Beneficiary") is entitled to claim under any existing policy of insurance
     in respect of which the Company is the insured person then no such matter
     shall be the subject of a Warranty Claim unless and until the Beneficiary
     shall have made a claim against the relevant insurer and any amount
     recovered under such insurance policy (or which could have been recovered
     had such policies been maintained) shall then reduce by the amount
     recovered or extinguish any such Warranty Claim.

9.5  Where the Purchaser or the Beneficiary is at any time entitled to recover
     from some other person any sum in respect of any matter giving rise to a
     claim under the Warranties or under or in connection with this Agreement,
     the Beneficiary shall undertake all reasonable steps to enforce such
     recovery prior to taking action against the Seller (other than to notify
     the Seller of the claim against the Seller) and, in the event that the
     Beneficiary shall recover any amount from such other person, the amount of
     the claim against the Seller shall be reduced by the amount recovered.

9.6  If the Seller pays at any time to a Beneficiary an amount pursuant to a
     claim in respect of the Warranties or under or in connection with this
     Agreement and the Beneficiary subsequently becomes entitled to recover from
     some other person any sum in respect of any matter giving rise to such
     claim, the Beneficiary shall take all reasonable steps to enforce such
     recovery, and shall forthwith, following such recovery, repay to the Seller
     so much of the amount paid by the Seller to the Beneficiary as does not
     exceed the sum actually recovered from such other person.

9.7  If any amount is repaid to the Seller by a Beneficiary pursuant to clause
     9.6 above, an amount equal to the amount so repaid shall be deemed never to
     have been paid by the Seller to the Purchaser for the purposes of
     calculating the Seller's total aggregate liability under this clause 9.

9.8  (a)  The Purchaser shall or shall procure that, upon a Beneficiary becoming
          aware of any claim, action or demand against it or matter likely to
          give rise to any of these in respect of the Warranties or under or in
          connection with this Agreement, the Beneficiary shall:

          (i)  as soon as reasonably practicable, notify the Seller by written
               notice as soon as it appears to the Purchaser that the Seller is
               or may become liable under the Warranties or under or in
               connection with this Agreement for any assessment or claim of a
               third party received by or coming to the notice of the Purchaser;

          (ii) subject to the Seller indemnifying the Beneficiary to its
               reasonable satisfaction against any liability, costs, damages or
               expenses which may be incurred thereby, take such reasonable
               action and give such information and access to personnel,
               premises, chattels, documents and records to the Seller and their
               professional advisers as the Seller may reasonably request;

          (iii) at the request of the Seller, allow the Seller to take the sole
               conduct of such actions as the Seller may reasonably deem
               appropriate in connection with any such assessment or claim in
               the name of the Beneficiary and in that connection the Purchaser
               shall give or cause to be given to the Seller all such assistance
               as the Seller may reasonably require in avoiding, disputing,
               resisting, settling, compromising, defending or appealing any

<PAGE>

                                     - 11 -

               such claim and shall, at the Seller's expense, instruct such
               solicitors or other professional advisers as the Seller may
               nominate to act on behalf of the Beneficiary, as appropriate, but
               to act in accordance with the Seller's sole instructions;

          (iv) make no admission of liability, agreement, settlement or
               compromise with any third party in relation to any such claim or
               adjudication without the prior written consent of the Seller; and

          (v)  take all reasonable action to mitigate any loss suffered by the
               Beneficiary in respect of which a claim could be made under the
               Warranties.

     (b)  In any event, the Seller shall be entitled at any stage and at its
          sole discretion to settle any such third party assessment or claim and
          shall notify the Purchaser of its decision so to settle such
          assessment or claim.

9.9  (a)  The only Warranties given in respect of Intellectual Property or
          hardware or agreements relating thereto are those contained in
          paragraph I of Schedule IV and none of the other Warranties shall be
          deemed to be given in relation to Intellectual Property or hardware or
          agreements relating thereto.

     (b)  The only Warranties given in respect of employment matters or
          agreements relating thereto are those contained in paragraph L of
          Schedule IV and none of the other Warranties shall be deemed to be
          given in relation to employment matters or agreements relating
          thereto.

     (c)  The only Warranties given in respect of pensions arrangements or
          agreements relating thereto are those contained in paragraph M of
          Schedule IV and none of the other Warranties shall be deemed to be
          given in relation to pensions arrangements or agreements relating
          thereto.

     (d)  The only Warranties given in respect of property related matters or
          agreements relating thereto are those contained in paragraph F of
          Schedule IV and none of the other Warranties shall be deemed to be
          given in relation to property related matters or agreements relating
          thereto.

     (e)  The only Warranties given in respect of environmental matters are
          those contained in paragraph G of Schedule IV and none of the other
          Warranties shall be deemed to be given in relation to environmental
          matters.

10.  Employees and Pensions

10.1 Any historic liability in respect of the Employees' employment by the
     Seller or a member of the Seller's Group prior to the Completion Date and
     any liability in respect of the Employees arising as a result of or
     incurred by the Company by virtue of any previous business transfer
     (including without limitation any claim arising out of or in connection
     with any change in the terms of the Employees' employment following any
     previous business transfer (other than in relation to the terms of
     employment offered by the Company) or any failure to inform or consult the
     Employees or any other person or their respective representatives in
     respect of any previous business transfer) shall be the liability of the
     Seller.

10.2 The Seller agrees to indemnify and keep indemnified the Company and the
     Purchaser against all losses, costs, liabilities, expenses, actions,
     proceedings, claims and demands arising out of or in connection with:

     (a)  the liability referred to at 10.1;

     (b)  any claim by any person other than an Employee relating to that
          person's employment with the Seller or the relevant member of the
          Seller's Group or the Company or the termination thereof, to the
          extent that the same relates to a period prior to the Completion Date.

<PAGE>

                                     - 12 -

10.3 If as a result of any previous business transfer, any contract of
     employment of a person other than an Employee is alleged or found to have
     effect as if originally made between such person and the Company, the
     Company shall inform the Seller in writing and may within 28 days after so
     informing the Seller terminate that contract forthwith and the Seller shall
     indemnify the Company and the Purchaser against all losses, costs,
     liabilities (including without limitation any redundancy payments, damages
     or compensation to the extent that the same are reasonably incurred),
     expenses, actions, proceedings, claims and demands arising out of or in
     connection with such termination and against any sums paid to or in
     relation to such person in respect of his or her employment by the Company
     from the date of the relevant transfer to the date of such termination.

10.4 The Purchaser shall procure that within one month following the Completion
     Date each of the Employees who is immediately before the Completion Date an
     active member of one of the Seller's Pension Schemes is offered membership
     of a pension scheme nominated by the Purchaser which is an approved
     personal pension scheme (the "Purchaser's Scheme") and which is capable of
     receiving all the accrued benefits of the Employees under the Seller's
     Pension Schemes (including any contracted-out rights) to which the Seller's
     Pension Scheme can make transfer payments without prejudicing the approval
     of the Seller's Pension Schemes.

10.5 The Seller shall within two months following the Completion Date use all
     reasonable endeavours to procure that each of the Employees who is a member
     of one of the Seller's Pension Schemes is invited to consent (in a form
     agreed with the Seller) within eight weeks following the invitation to a
     transfer of assets being made for such Employee from the relevant Seller's
     Pension Scheme to the Purchaser's Scheme. Such invitations to consent to
     transfer shall include reference to the fact that neither the Seller nor
     the Purchaser is authorised to give investment advice in connection with
     the transfer and that the responsibility for obtaining any such advice
     rests with the Employee concerned.

10.6 Subject to clauses 10.4 and 10.5 being duly performed, the Seller will use
     reasonable endeavours to ensure that the trustees of the relevant Seller's
     Pension Scheme transfer to the Purchaser's Pension Scheme an amount in
     respect of each Employee who consents to such transfer equal to the greater
     of the value of that Employee's accrued benefits based on a past service
     reserve method of calculation made in accordance with the April 2000
     valuation assumptions applicable to the Chubb Pension Plan (for Chubb
     Pension Plan members) and the April 1998 valuation assumptions applicable
     to the Chubb Security Fund (for Chubb Security Fund members), calculated by
     an actuary appointed by the Seller as at the Completion Date or the
     unreduced cash equivalent determined in accordance with the Pension Schemes
     Act 1993 and regulations thereunder.

10.7 The Seller shall use all reasonable endeavours to ensure that prior to the
     Completion Date all of the Employees accept offers of employment with the
     Company, such offers to take effect no later than the Completion Date, on
     the terms contained in the standard employment contract in the agreed
     terms.

10A  Licence to store and maintain SMC Rack

10A.1 During the Licence Period, the Purchaser shall allow the Seller and any
     member of the Seller's Group to store within the Demised Premises the SMC
     Rack and the provisions of this clause 10A shall apply throughout the
     Licence Period.

10A.2 The Purchaser shall provide and shall pay for all electricity and other
     power supplies as may be required by the Seller and any member of the
     Seller's Group for the Seller's or any member of the Seller's Group's use,
     maintenance, removal, installation, replacement or renewal of the SMC Rack.

10A.3 The Purchaser shall not without the prior consent of the Seller or any
     member of the Seller's Group use, operate, relocate, remove, or in any way
     tamper with the SMC Rack.

10A.4 The Purchaser shall afford to the Seller and any member of the Seller's
     Group such rights of access to the Demised Premises and to the SMC Rack
     within the Demised Premises

<PAGE>

                                     - 13 -

     as may be required by the Seller or any member of the Seller's Group for
     the purposes of repairing, maintaining, removing, installing, replacing and
     renewing the SMC Rack, subject to the following provisions:

     (1)  Save in the case of emergency, such access by the Seller or any member
          of the Seller's Group to the Demised Premises and to the SMC Rack (1)
          must be notified to the Purchaser at least 24 hours before the
          intended access takes place and (2) must take place on a Monday,
          Tuesday, Wednesday, Thursday or Friday of any week.

     (2)  The Seller or any member of the Seller's Group shall exercise the
          aforementioned right of access in such a manner as to cause the least
          practicable inconvenience to the Purchaser.

     (3)  The Seller or any member of the Seller's Group shall make good any
          damage caused to the Demised Premises by virtue of the taking of the
          aforementioned right of access.

10A.5 The Purchaser shall procure that its successors and assignees vest in the
     tenant's interest in the Lease shall be bound by the obligations and
     restrictions imposed upon the Purchaser in terms of this clause 10A and
     shall if the Seller or any member of the Seller's Group so requires,
     procure that its successors or assignees, as the case may be, enter into
     written undertakings to that effect direct with the Seller or any member of
     the Seller's Group.

10A.6 (a) If the lessor of the Lease validly requires, under a term of the
          Lease, the Company to remove the SMC Rack or cease to afford the
          access referred to in this clause 10A, the Company shall be entitled
          so to do on giving reasonable notice to the Seller.

     (b)  The Purchaser agrees not to take any action or omit to do anything
          which may precipitate any request by the lessor contemplated by clause
          10A.6(a), to notify the Seller immediately upon it or the Company
          becoming aware of any such request, and to take all such action and
          procure that the Company shall take all such action as the Seller may
          request to, at the Seller's expense, dispute and contest any such
          request.

10B  15 Wheeler Gate, Nottingham

10B.1 In respect of the Company's prior occupation of property at 15 Wheeler
     Gate, Nottingham NG1 2NA which is disclosed in Schedule Three of the
     Disclosure Letter, the Company is entitled to a refund of a deposit which
     is disclosed in Schedule Three, Supplemental Disclosure Documents, item 5
     (the "Refund").

10B.2 The Seller shall be entitled to the Refund or such part of the Refund as
     may be provided by MWB Business Exchange Limited. For the avoidance of
     doubt, regardless of the date on which the Refund is provided by MWB
     Business Exchange Limited, the Purchaser shall not be entitled to the
     Refund and shall pay or procure to be paid to the Seller forthwith such
     part of the Refund which may be received by the Purchaser or the Company.

10D  VAT

10D.1 The parties acknowledge that the Company will before Completion make an
     application to be VAT registered (as a separately registered entity) under
     the Value Added Tax Act 1994.

10D.2 The parties agree that the Seller and/or the Guarantor and/or the advisers
     of the same (together with the Company) shall be responsible for the
     preparation and submission of the application referred to in 10D.1 above.

<PAGE>

                                     - 14 -

10D.3 The Purchaser hereby consents to the making of the application referred to
     in clause 10D.1 above and agrees to co-operate in the making of such
     application.

10D.4 The parties agree to procure that the Company makes all claims which it is
     able to make in accordance with Regulation 111 of the VAT Regulations 1995
     (the "Regulations") in respect of supplies made to the Company before the
     date the Company was registered or required to be registered under the
     Value Added Tax Act 1994 ("VATA") or otherwise.

10D.5 The Purchaser agrees to procure that the Company shall not join any group
     for VAT purposes in accordance with section 43 VATA and that no application
     shall be made for the same until after the date on which the Company has
     made its first return (as referred to in Regulation 111(3) of the
     Regulations) as a separately registered entity under the VATA.

10D.6 The parties agree that:

          (i)  new invoices (the "New Invoices") for supplies made to the
               Company by members of the Seller's Group before the date of this
               Agreement may be issued to the Company by the relevant members of
               the Seller's Group before Completion up to an amount exclusive of
               VAT of (pound)6.7 million; and

          (ii) the New Invoices will state the VAT charged on relevant supplies
               and the Company shall pay an amount in respect of such VAT to the
               relevant members of the Seller's Group if and to the extent the
               Company recovers by way of credit or repayment the VAT on such
               supplies as input tax.

10D.7 The parties agree that:

          (i)  invoices (the "Future Invoices") for taxable supplies made to the
               Company by members of the Seller's Group after the date of this
               Agreement and before Completion may be issued to the Company
               before Completion by the relevant member of the Seller's Group;
               and

          (iii) the Future Invoices (including the VAT invoice to be issued in
               respect of the Recharged Expenditure) will state the VAT charged
               on the relevant supplies and the Company shall pay an amount in
               respect of such VAT to the relevant members of the Seller's Group
               if and to the extent the Company recovers by way of credit or
               repayment the VAT on such supplies as input tax.

10D.8 Payments in respect of VAT due under clauses 10D.6 and 10D.7 above shall
     be made by the Company on the third Business Day after the date of recovery
     by the Company as referred to in the relevant clauses and if the Company
     does not make such payment on such day, the amounts due shall carry
     interest from such date until the date of payment at the rate of three per
     cent above the base rate from time to time of Barclays Bank PLC.

10D.9 The Purchaser agrees that the Seller (together with its advisers) shall
     prepare all claims as are referred to in 10D.4 above and any correspondence
     associated therewith and agrees to procure that the Company shall submit
     the same or permit the same to be submitted on its behalf without
     alteration.

10D.10 The Purchaser agrees that the Seller (together with its advisers) shall
     have the conduct (at the Seller's expense) of any dispute with HM Customs &
     Excise in respect of whether the Company is entitled to be registered under
     the VATA and/or in respect of the time from which it is so entitled and/or
     in respect of the validity of any claims made pursuant to Regulation 111 of
     the Regulations as referred to above (such conduct including decisions as
     to whether to make any relevant appeals and the conduct of any such
     appeals).

<PAGE>

                                     - 15 -

11.  Confidentiality and announcements

11.1 In consideration of the Purchaser agreeing to buy the Shares on the terms
     of this Agreement, the Seller agrees with the Purchaser that (save as may
     be required by law, and then only to the extent so required) it will use
     all reasonable endeavours to keep confidential (other than in accordance
     with clause 11.2) any confidential information in relation to the affairs
     or business of the Company.

11.2 Save for the publication of the announcements in the agreed terms, no
     announcement or statement about this Agreement or the subject matter of, or
     any matter referred to in, this Agreement shall be made or issued before,
     on or after Completion by or on behalf of either of the parties without the
     prior written approval of the other party (such approval not to be
     unreasonably withheld or delayed) PROVIDED that nothing shall restrict the
     making by either Party (even in the absence of the other party's agreement)
     of any statement which may be required by law or called for by the
     requirements of the Stock Exchange, but then only to the extent so
     required.

12.  Further assurance and availability of information

12.1 The parties shall execute and deliver all such instruments and other
     documents and take all such actions as each may from time to time
     reasonably require in order to give full effect to the provisions of this
     Agreement.

12.2 The Seller shall cause to be made available to the Purchaser all
     information in its possession or under its control which the Purchaser may
     from time to time reasonably require (after Completion) relating to the
     business and affairs of the Company and shall permit the Purchaser and its
     representatives on reasonable advance notice to have access to documents
     containing such information and to take copies thereof.

13.  Interest

     If any amount required to be paid under this Agreement is not paid when it
     is due, such amount shall bear interest at the rate of three per cent per
     annum over the base lending rate of National Westminster Bank PLC from time
     to time, calculated on a daily basis for the period from the relevant due
     date for payment up to and including the date of actual payment, as well
     after as before any judgment.

14.  Continuing obligations and assignment

14.1 Each of the obligations, warranties, representations, indemnities and
     undertakings accepted or given by the Seller or the Purchaser under this
     Agreement or any document referred to herein ("Obligations") shall continue
     in full force and effect notwithstanding Completion taking place and shall
     be binding on their respective successors.

14.2 The rights of each of the parties to this Agreement may be assigned only
     with the prior written consent of the other parties.

15.  Costs

     Each party shall pay its own costs and expenses in relation to the
     negotiation, preparation, and implementation of this Agreement (and the
     documents referred to herein), including the fees and disbursements of
     their respective legal, accountancy and other advisers.

16.  Notices

16.1 Any notice or other communication to be given under this Agreement shall be
     in writing, shall be deemed to have been duly served on, given to or made
     in relation to a party if it is

<PAGE>

                                     - 16 -

     left at the authorised address of that party, posted by first class
     addressed to that party at such address, or sent by facsimile transmission
     to a machine situated at such address and shall if:

     (a)  personally delivered, be deemed to have been received at the time of
          delivery;

     (b)  posted to an inland address in the United Kingdom, be deemed to have
          been received on the second Business Day after the date of posting and
          if posted to an overseas address, be deemed to have been received on
          the fifth Business Day after the date of posting; or

     (c)  sent by facsimile transmission, be deemed to have been received upon
          receipt by the sender of a facsimile transmission report (or other
          appropriate evidence) that the facsimile has been transmitted to the
          addressee;

     PROVIDED that where, in the case of delivery by hand or facsimile
     transmission, delivery or transmission occurs after 6.00 pm on a Business
     Day or on a day which is not a Business Day, receipt shall be deemed to
     occur at 9.00 am on the next following Business Day.

16.2 For the purposes of this clause the authorised address of each party shall
     be the address set out at the heading of this Agreement or such other
     address as that party may notify to the others in writing from time to time
     in accordance with the requirements of this clause.

17.  Severability

17.1 If any provision of this Agreement (or of any document referred to herein)
     is held to be illegal, invalid or unenforceable in whole or in part the
     legality, validity and enforceability of the remaining provisions of this
     Agreement (or such document) shall not in any way be affected or impaired
     thereby.

18.  Entire agreement and variation

18.1 This Agreement (together with any documents referred to herein) contains
     the entire agreement and understanding of the parties and supersedes all
     prior agreements, understandings or arrangements (both oral and written)
     relating to the subject matter of this Agreement.

18.2 Each of the parties acknowledges and agrees that:

     (a)  it does not enter into this Agreement and the documents referred to
          herein on the basis of and does not rely, and has not relied, upon any
          statement or representation (whether negligent or innocent) or
          warranty or other provision (in any case whether oral, written,
          express or implied) made, given or agreed to by any person (whether a
          party to this Agreement or not) except those expressly set out or
          referred to in this Agreement and the documents referred to herein and
          the only remedy or remedies available in respect of any
          misrepresentation or untrue statement made to it shall be a claim for
          breach of contract under this Agreement; and

     (b)  this clause 18.2 shall not apply to any statement, representation or
          warranty made fraudulently or to any provision of this Agreement which
          was induced by, or otherwise entered into as a result of, fraud, for
          which the remedies shall be all those available under the law
          governing this Agreement.

18.3 No variation, supplement, deletion or replacement of or from this Agreement
     or any of its terms shall be effective unless made in writing and signed by
     or on behalf of each party.

19.  General provisions

19.1 Time shall be deemed to be of the essence in this Agreement.

<PAGE>

                                     - 17 -

19.2 For the avoidance of doubt the parties agree that the company cars used by
     the Employees have not been and will not be transferred to the Company by
     the Purchaser. Accordingly, from Completion, the Employees will cease to be
     entitled to use such cars.

19.3 Any waiver of a breach of any of the terms of this Agreement or of any
     default hereunder shall not be deemed to be a waiver of any subsequent
     breach or default and shall in no way affect the other terms of this
     Agreement.

19.4 No failure to exercise and no delay on the part of any party in exercising
     any right, remedy, power or privilege of that party under this Agreement
     and no course of dealing between the parties shall be construed or operate
     as a waiver thereof, nor shall any single or partial exercise of any right,
     remedy, power or privilege preclude any other or further exercise thereof
     or the exercise of any other right, remedy, power or privilege. The rights
     and remedies provided by this Agreement are cumulative and are not
     exclusive of any rights or remedies provided by law.

19.5 The Purchaser shall have, absent fraud, no right whatsoever on or after the
     date of this Agreement to terminate or rescind this Agreement.

20.  Guarantee

20.1 In consideration of the Purchaser entering into this Agreement with the
     Seller, the Guarantor hereby irrevocably and unconditionally guarantees to
     the Purchaser the full, prompt and complete performance by the Seller of
     all its obligations under this Agreement and the due and punctual payment
     on demand of all sums now or subsequently due and payable by the Seller to
     the Purchaser under or pursuant to this Agreement.

20.2 The guarantee contained in this clause is a continuing guarantee and shall
     remain in force until all the obligations of the Seller under this
     Agreement have been fully performed and all sums payable by the Seller have
     been fully paid. Save in respect of the Retention it is independent of
     every other security which the Purchaser may at any time hold for the
     obligations of the Seller under this Agreement.

20.3 The obligations of the Guarantor shall not be affected by any act,
     omission, matter or thing which, but for this provision, might operate to
     release or otherwise exonerate the Guarantor from its obligations or affect
     such obligations, including without limitation and whether or not known to
     the Guarantor:

     (a)  any variation of this Agreement or any time, indulgence, waiver or
          consent at any time given to the Seller or any other person;

     (b)  any compromise or release of, or abstention from obtaining, perfecting
          or enforcing any security or other right or remedy whatsoever from or
          against, the Seller or any other person; or

     (c)  any legal limitation, disability, incapacity or other circumstance
          relating to the Seller or any other person;

     (d)  any irregularity, unenforceability or invalidity of any obligations of
          the Seller under this Agreement, or the dissolution, amalgamation,
          reconstruction or insolvency of the Seller.

21.  Governing law and jurisdiction

21.1 This Agreement (together with all documents to be entered into pursuant to
     it which are not expressed to be governed by another law) shall be governed
     by, construed and take effect in accordance with English law.

21.2 The courts of England shall have exclusive jurisdiction to settle any
     claim, dispute or matter of difference which may arise out of or in
     connection with this Agreement (including

<PAGE>

                                     - 18 -

     without limitation claims for set-off or counterclaim) or the legal
     relationships established by this Agreement.

21.3 Each of the parties hereto agrees that in the event of any action between
     any of the parties hereto being commenced in respect of this Agreement or
     any matters arising under it, the process by which it is commenced, (where
     consistent with the applicable court rules) may be served on them in
     accordance with clause 16.

As Witness the hands of the parties or their duly authorised representatives the
day and year first above written.

<PAGE>

                                     - 19 -

                                   Schedule I

                                   The Company

A.   Chubb Information Security Limited

 1.   Registered number                3904130

 2.   Registered office                Pentagon House, Sir Frank Whittle Road,
                                       Derby DE21 4XA, United Kingdom

 3.   Date of incorporation            11 January 2000

 4.   Class of company                 Private, limited by shares

 5.   Authorised share capital         (pound)10,000,000

 6.   Issued share capital             (pound)6,730,000

 7.   Directors'/Shareholders' Loans   Nil

 8.   Directors                        1. Andrew Michael Burton
                                       2. Westminster Securities Limited
                                       3. Williams Management Services Limited

 9.   Secretary                        Robert Christopher Hill

10.   Accounting reference date        31 December

11.   Auditors                         PricewaterhouseCoopers

12.   Tax district and reference       Derby 2 - 2527478803045

13.   Members                          Williams Security Limited

14.   Mortgages and Charges            Nil

<PAGE>

                                     - 20 -

                                   Schedule II

                                  The Property

                               Leasehold Property

           Address                                        Lease Details
           -------                                        -------------

Former reservoir, Watley                          The Lease between Southern
Lane, Twyford, near                               Water Services Limited and
Winchester, Hampshire, all as                     Security Monitoring Centres
more particularly described                       Limited dated 24 December
in the Lease                                      1997 as amended by the
                                                  Licence to Assign and Deed of
                                                  Variation between Southern
                                                  Water Services Limited,
                                                  Security Monitoring Centres
                                                  Limited and the Company dated
                                                  20 February 2001

<PAGE>

                                     - 21 -

                                  Schedule III

                                    Employees

Andy Burton
Ian Stephens
David Matthews
Andy Cash
Paul Gardner
Mark Maciw
David Cutler
Richard Trevorah
Alison Prosser
Gordon May
Lorraine Scrivener
David Godley
Ed Parker
Chris Jaycock
Linda Hardy
Richard Everest
Brian Sparke
Deryk Ville
Randy Krzak
Angela Saville

<PAGE>

                                     - 22 -

                                   Schedule IV

                                   Warranties

In this Schedule "Encumbrance" includes any charge, debenture, mortgage, pledge,
lien, assignment, hypothecation, security interest, title retention or other
security agreement or arrangement or other third party right.

A.   Preliminary

     The information set out in Schedule I is true and accurate in all material
     respects and so far as the Seller is aware there is no matter which renders
     any of such information untrue or misleading.

B.   The Accounts

B.1  The Accounts show a reasonably accurate view of the state of affairs and
     profit or loss of the Company as at and for the period in respect of which
     they have been prepared, but it is hereby acknowledged that they are
     summary management accounts and are not prepared on a statutory basis.

B.2  If a balance sheet for the Company were to be drawn up as at the Completion
     Date on the same basis as set out in the Warranty B.1 in respect of the
     Accounts, it would show (other than, for the avoidance of doubt, the
     Inter-Company Debt) no liabilities owing by the Company other than in
     relation to any matter in respect of which the Purchaser has given its
     consent pursuant to clause 5.

C.   Business since the Balance Sheet Date

C.1  Since the Balance Sheet Date the Company has in all material respects
     carried on its business in the ordinary and usual course, has in all
     material respects been properly managed and has complied, in all material
     respects, with all applicable laws and has maintained all material
     licences, consents and authorisations of any nature whatsoever (public or
     private) which are necessary to carry on the Business from time to time.

D.   Share Capital and constitution of the Company

D.1  The Register of Members of the Company contains complete and accurate
     records of its members.

D.2  There is no option, right of pre-emption, right or obligation to acquire,
     redeem or convert or Encumbrance on, over or affecting the share capital
     (whether issued or unissued and whether or not authorised capital) of the
     Company and neither has the Seller or the Company agreed to give or create
     any of the foregoing and, so far as the Seller is aware, no person has
     claimed to be entitled to any of the foregoing.

D.3  The copy of the Memorandum and Articles of Association set out in the Data
     Room Index as Volume 1, document 1.1 is up to date, true and complete and
     has annexed thereto a copy of every resolution, agreement or other document
     required to be annexed thereto pursuant to section 380 Companies Act 1985.

D.4  The Shares comprise all the shares in issue in the capital of the Company.

E.   Assets

E.1  The Company is the absolute owner of and is in actual possession of all the
     material assets used in the course of the Business with full right and
     power to sell the same in

<PAGE>

                                     - 23 -

     each case with full title guarantee. The Company has not created or agreed
     to create any Encumbrance over any material part of its undertaking or
     assets.

E.2  So far as the Seller is aware, no asset used in the course of the Business
     and hired, leased or rented by or obtained on hire-purchase by the Company
     has been or is liable to be retaken into possession by the owner thereof.

E.3  The Company owns all of the assets that comprise the fixed assets of the
     Company as set out in the Accounts including the assets set out in the
     fixed assets register set out in the Data Room Index as Volume 1, document
     17.

E.4  No member of the Seller's Group has knowingly taken any action that would
     prejudice the ability of the Company to deduct expenses or losses incurred
     by the Company for the purposes of computing its liability to United
     Kingdom corporation tax at any time or to utilise capital allowances that,
     but for such action, would be available to the Company.

     For the avoidance of doubt, no warranty is given as to the availability to
     the Company of any expenses, losses or capital allowances for United
     Kingdom corporation tax purposes.

F.   Property

F.1  The Property comprises all of the land and premises owned, occupied or
     otherwise used by the Company. The particulars of the Property shown in
     Schedule II are true and correct.

F.2  The Company has not entered into any agreement to acquire or dispose of any
     land or premises or any interest therein which has not been completed.

F.3  The Property is not subject to:

     (a)  any matters which adversely affect to a material extent the proper
          use, occupation or enjoyment of the Property for the purpose for which
          it is now used and all matters which benefit the Property have where
          necessary been properly protected by registration; and

     (b)  any outgoings other than the outgoings for which the Company is liable
          in terms of the Lease and the Company is not in arrears with any such
          outgoings.

F.4  No written notice has been received by the Company or, so far as the Seller
     is aware, any member of the Seller's Group in respect of the Company's or
     Security Monitoring Centre Limited's non-compliance with any agreement,
     covenant, restriction, applicable statutory and by-law requirement or other
     matter to which the Property is subject and in so far as the Seller is
     aware there are no claims or disputes or outstanding orders or notices
     affecting the Company's interest in the Property.

G.   Environmental/health and safety

G.1  So far as the Seller is aware, there have been no material breaches since
     24 December 1997 by the Company or Security Monitoring Centres Limited of
     Environmental Laws and there are no matters whatsoever occurring since that
     date which have or are likely to give rise to any claims, actions,
     proceedings, expenses or liabilities against the Company arising under
     Environmental Laws concerning contamination or decontamination or other
     remediation of the Property or land adjoining the Property or Controlled
     Waters at or beneath the Property.

G.2  There are annexed to the Disclosure Letter complete copies of any
     environmental audit reports relating to the Property which are in the
     possession or control of the Seller or any member of the Seller's Group and
     were conducted in the last year.

<PAGE>

                                     - 24 -

H.   Commercial agreements and arrangements

H.1  The Seller has disclosed to the Purchaser in the Disclosure Letter all
     material contracts, commitments and obligations of and offers by the
     Company now outstanding or which will become capable of giving rise to a
     material contract by an order or acceptance by another party or parties.

H.2  Neither the Company nor, so far as the Seller is aware, any other party to
     any material agreement or arrangement with the Company is in default to any
     material extent thereunder. So far as the Seller is aware, there are no
     circumstances likely to give rise to such a default.

I.   Intellectual Property Rights

     General

I.1  The Company does not own any registered Intellectual Property or
     applications therefor.

I.2  So far as the Seller is aware, no Employee or employee of the relevant
     member of the Seller's Group or other person has claimed in writing any
     right, payment or compensation in respect of any Intellectual Property used
     in connection with the Business.

I.3  So far as the Seller is aware, the activities of the Business do not
     infringe the Intellectual Property owned by any third party and, so far as
     the Seller is aware, no third party is infringing any Intellectual Property
     used in the Business.

     Licences, etc

I.5  Save as specifically disclosed in the Disclosure Letter there are no
     subsisting material licences of Intellectual Property granted to or by any
     person carrying on the Business and no third party has applied for licences
     of right or compulsory licences in any jurisdiction.

J.   Information technology

J.1  Copies of all material licences, undertakings, settlements, consents,
     agreements and arrangements relating to the escrow, ownership, possession,
     maintenance and use of the hardware and software used in the Business have
     been provided to the Purchaser and, so far as the Seller is aware, no party
     to such licences, undertakings, settlements, consents, agreements and
     arrangements is in breach of such arrangements and no written claim
     regarding such breach has been received or made by the Company in the two
     years prior to the date hereof.

K.   Compliance and litigation

K.1  Save as claimant in proceedings for the collection of debts (not exceeding
     (pound)30,000 in the aggregate) arising in the ordinary course of its
     business, the Company is not now engaged in any litigation or arbitration
     proceedings, there are no litigation or arbitration proceedings pending or
     threatened by or against the Company, no injunction has been granted
     against the Company, the Company has given no undertaking to any court or
     to any third party arising out of any legal proceedings and there is no
     matter or fact in existence which might give rise to the same or form the
     basis of any criminal prosecution against the Company.

K.2  So far as the Seller is aware, no member of the Seller's Group is engaged
     in any proceedings (actual, pending or threatened) of the type referred to
     in K.1 in connection with its conduct of the Business or any part of it and
     there is no matter or fact in existence which might give rise to the same.

K.3  So far as the Seller is aware, no order has been made or petition presented
     or resolution passed for the appointment of an administrator or receiver in
     relation to the Company, or for its winding-up, nor has any distress,
     execution or other process been levied against the Company.

<PAGE>

                                     - 25 -

L.   Employees

L.1  Copies of:

     (a)  the service agreements of each of the Employees; and

     (b)  the terms of all consultancy agreements with the Seller or the
          Seller's Group relating to the Business,

     have been disclosed.

L.2  There are no employees of the Company other than the Employees.

L.3  Neither the Company nor the Seller nor the relevant member of the Seller's
     Group is liable to make any payment to any Employee or former employee
     engaged in the Business by way of damages (whether for breach of contract
     or otherwise) or compensation for loss of office or employment or for
     redundancy, protective awards, wrongful dismissal or unfair dismissal or
     for failure to comply with any order for reinstatement or re-engagement (or
     similar rights of action under Canadian provincial or federal law) or for
     any other liability accruing from the termination of any contract of
     service or for services of any Employee or any employee or former employee
     of the Company, the Seller or a member of the Seller's Group who is or was
     engaged in the Business and the Employment Statutes have in all material
     respects been duly complied with by the Company in relation to its
     employees.

L.4  Neither the Company nor the Seller nor the relevant member of the Seller's
     Group is engaged or involved in any dispute arising out of, affected by or
     otherwise relating to the provisions of the Employment Statutes in relation
     to the Employees, and so far as the Seller is aware there are no
     circumstances which could give rise to any such dispute.

L.5  No trade union is recognised by the Company, the Seller or the relevant
     member of the Seller's Group in relation to the Employees for any purpose
     whatsoever.

M.   Pensions

M.1  The Company has no obligation (actual or contingent and whether legally
     enforceable or not) to provide or contribute to the provision of any
     pension or like benefit for or in respect of any of the Employees.

M.2  The Disclosure Letter contains an accurate description of the measures
     taken by and in relation to the Seller's Pension Schemes to comply with the
     requirement that men and women members thereof be subject to equal normal
     retirement ages and contains details of those of the Employees who are both
     members of the Seller's Pension Schemes and have past part-time service
     with the Seller's Group which was not pensionable because the Seller's
     Pension Scheme excluded part-time employees.

M.3  The Disclosure Letter contains a list of all of the Employees who are
     members of or have any rights to benefits under the Seller's Pension
     Schemes.

M.4  So far as the Seller is aware (which expression shall mean, for the
     purposes of Warranties M.4 and M.7 only, Roy Brown (Divisional Finance
     Director, Chubb plc) having made reasonable enquiries of Warwick Jones
     (Group Pensions Manager for the Seller's Group)), the Seller's Pension
     Schemes have at all times been operated in all material respects in
     accordance with their respective governing documentation and in all
     material respects in accordance with all applicable laws and regulatory
     requirements including, without limitation, the requirements of Article 141
     of the EU Treaty of Rome relating to equal benefits and admission to
     membership.

M.5  Other than for the month current at the date of this Agreement, all amounts
     due to the trustees of the Seller's Pension Schemes in respect of any of
     the Employees have been paid.

<PAGE>

                                     - 26 -

M.6  Each of the Seller's Pension Schemes is approved as an exempt approved
     scheme within the meaning of Chapter I of Part XIV of ICTA 1988.

M.7  So far as the Seller is aware, there are no actions, claims or suits
     outstanding, pending or threatening against the trustees or administrators
     of the Seller's Pension Schemes in respect of any act, event or omission or
     other matter arising out of or in connection with the Seller's Pension
     Scheme or otherwise in relation to the provision of any relevant benefit in
     respect of any of the Employees.

<PAGE>

                                     - 27 -

                                   Schedule V

                            Form of deed of covenant

This Deed of Covenant is made the       day of    2001
                                  -----        --
Between:

(1)  Chubb Plc a company registered in England and Wales under number 4034666
     whose registered office is at Pentagon House, Sir Frank Whittle Road, Derby
     DE21 4XA (collectively, the "Covenantor");

(2)  Chubb Information Security Limited a company registered in England and
     Wales under number 3904130 whose registered office is at Pentagon House,
     Sir Frank Whittle Road, Derby DE21 4XA (the "Company"); and

(3)  Baltimore Technologies plc a company registered in England and Wales under
     number 2643615 whose registered office is at The Square, Basing View,
     Basingstoke, Hampshire RG21 4EG (the "Purchaser").

Whereas:

Pursuant to the provisions of an Agreement dated o March 2001 between amongst
others the Covenantor and the Purchaser, (the "Sale Agreement") the Purchaser
has agreed to acquire the entire issued share capital of the Company and the
Covenantor has agreed to enter into this Deed.

Operative terms:

1.   Interpretation

1.1  In this Deed unless the context or subject matter otherwise requires,
     expressions defined in the Sale Agreement shall have the same meanings and
     in addition the following expressions shall have the following meanings:

     "Listed Territories" has the meaning ascribed to it in the Trade Mark
     Licence Agreement;

     "Restricted Business" the business as described in the Sale Agreement under
     the definition "Business";

     "Restricted Area" the world;

     "Restricted Period" the period from the date of the Trade Mark Licence
     Agreement to 31 December 2006; and

     "Trade Mark Licence Agreement" the trade mark licence agreement as defined
     in the Sale Agreement.

1.2  The provisions of clauses 1.2 to 1.4 (inclusive) of the Sale Agreement
     shall apply in this Deed (with the necessary modifications) as if repeated
     in this Deed and set out in full herein.

2.   Covenants

2.1  Subject to clause 2.5 the Covenantor hereby undertakes to the Company that
     it will not either alone or jointly with others, whether as principal,
     agent, manager, shareholder, independent contractor or in any other
     capacity, directly or indirectly through any other person, for his own
     benefit or that of others:

     (a)  at any time during the Restricted Period engage in or carry on or be
          interested in any Restricted Business within the Restricted Area in
          competition with the Company and/or the Purchaser (other than as a
          holder for investment of no more than 15 per cent of any class of
          shares or securities dealt in on a recognised stock exchange); or

<PAGE>

                                     - 28 -

     (b)  at any time during the Restricted Period canvass or solicit or accept
          orders for the supply of any services substantially similar to or
          otherwise competing with those supplied in the normal course of the
          Restricted Business from any person who has been a customer of the
          Company during the 12 months preceding the Completion Date, or induce
          or seek to induce any such person to cease being a customer of the
          Company; or

     (c)  at any time during the Restricted Period do anything knowingly to
          assist any competitor of the Company in any material way in carrying
          on or developing any Restricted Business in the Restricted Area; or

     (d)  at any time during the period expiring two years after Completion
          actively solicit any employee earning in excess of (pound)50,000 of
          the Company (an "Employee") to leave the employment of the Company,
          whether or not such Employee would by reason of so leaving commit a
          breach of his contract of employment, except in any such case where
          such Employee responds to a public advertisement.

2.2  Nothing in this Deed shall prevent or restrict the Covenantor or any of its
     subsidiary undertakings from time to time from acquiring any person or a
     business (a "Target") whose business includes a business (or businesses)
     (the "Competing Business") which competes with the Restricted Business,
     provided that the Competing Business is not a material part of the business
     of the Target. For the purposes of clauses 2.2 and 2.3, the Competing
     Business shall only be deemed "material" if the Competing Business
     contributed more than 30% of the total revenues of the Target, by reference
     to the most recent published accounts (or, if there are none, the
     management accounts).

2.3  If the Competing Business of a Target is material, then the Covenantor (or
     any of its subsidiary undertakings from time to time) may nevertheless make
     the acquisition but undertakes promptly after completion of the acquisition
     to notify the Purchaser in writing of this fact and to:

     (a)  offer the Purchaser the first right of refusal to acquire the
          Competing Business and if such offer is not accepted,

     (b)  dispose or cease the operation of the Competing Business within six
          months of the date when the Purchaser notifies the Covenantor in
          writing that it does not wish to acquire the Competing Business
          offered pursuant to clause 2.3(a) above. At the end of this period,
          the exemption in clause 2.2 shall cease to apply.

2.4  If by the third anniversary of this Deed the Company has not made use of
     the "Chubb" mark in a country which is included in the Listed Territories
     then the Covenantor may at any time thereafter notify the Purchaser that
     the covenant pursuant to clause 2.1 shall cease to apply in some or all of
     the countries in the Listed Territories in which no use of the "Chubb" mark
     has been made.

2.5  Each of the covenants contained in clause 2 is entirely separate and
     severable and enforceable accordingly. Each of such covenants is considered
     fair and reasonable in all the circumstances by the parties but in the
     event that any such restriction shall be found to be void or ineffective
     but would be valid and effective if some part thereof were deleted or the
     duration or area of application reduced such restriction shall apply with
     such modification as may be necessary to make it valid and effective.

3.   Assignment

     The rights of each of the parties to this Deed may be assigned only with
     the prior written consent of the other parties.

4.   General provisions

     The following provisions of the Sale Agreement shall apply to this Deed as
     if the same had been set out herein in full save that references therein to
     the Seller, its address and

<PAGE>

                                     - 29 -

     the Agreement respectively shall be construed as references to the
     Covenantor, its address specified in this Deed and this Deed:

     (a)   clause 16   Notices

     (b)   clause 17   Severability

     (c)   clause 18   Entire Agreement and Variations

     (d)   clause 19   General provisions

     (e)   clause 21   Governing law.

In witness whereof this Deed has been entered into the day and year first before
written.

EXECUTED as a deed by the             )
affixing of the Common Seal           )
of Chubb Information Security Limited )
in the presence of:                   )


                                      Director


                                      Director/Secretary


EXECUTED as a deed by the             )
affixing of the Common Seal           )
of Chubb plc                          )
in the presence of:                   )


                                      Director


                                      Director/Secretary


EXECUTED as a deed by the             )
affixing of the Common Seal           )
of Baltimore Technologies plc         )
in the presence of:                   )


                                      Director


                                      Director/Secretary

<PAGE>

Signed by Roy F. Brown                ) "Roy F. Brown"
for and on behalf of                  )
Williams Security Limited             )


Signed by Roy F. Brown                ) "Roy F. Brown"
for and on behalf of                  )
Chubb plc                             )


Signed by Simon Enoch                 ) "Simon Enoch"
for and on behalf of                  )
Baltimore Technologies plc            )