<PAGE>   1
                                                                   EXHIBIT 10.21


                            Dated 1st December 1995


                       G J KING & SON (HOME FARM) LIMITED


                                     - to -


                             ECC SIMULATION LIMITED


                                    - and -


                            ECC INTERNATIONAL CORP.


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                                     LEASE

                                - relating to -
                Unit 2 Home Farm Business Centre Home Farm Road
                              Brighton East Sussex

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                            [SPEECHLY BIRCHAM LOGO]


<PAGE>   2
THIS LEASE is made the 1st December 1995

(1)     G J KING & SON (HOME FARM) LIMITED whose registered office is situate 
        at G J King Business Centre Reeds Lane Sayers Common West Sussex BN6 
        9LS (hereinafter called "the Landlord")

(2)     ECC SIMULATION LIMITED (company registration number 1913659) whose 
        registered office is situate at Kingston Wharf Brighton Road Shoreham 
        by Sea West Sussex BN43 6RN (hereinafter called "the Tenant")

(3)     ECC INTERNATIONAL CORP a company incorporated in the State of Delaware 
        and whose principal place of business is at 175 Strafford Avenue Wayne 
        PA 19087-3377 U S A (hereinafter called "the Surety")

WITNESSETH as follows:-

1.      IN this lease where the context so admits the following expressions 
        shall have the following meanings respectively that is to say:-

        "the Landlord"
        means the Landlord hereinbefore named or such other person for the time 
        being entitled to the reversion immediately expectant upon the
        determination of the Term

        "the Tenant"
        means the Tenant hereinbefore named or such other person in whom the 
        Term shall for the time being be vested and wherever it includes more 
        than one person the covenants on the part of the Tenant hereinafter 
        contained shall be deemed to be joint and several

        "the Surety"
        means the Surety hereinbefore named or any person who shall have 
        covenanted with the Landlord pursuant to Clause 4(20)

                                      -1-
<PAGE>   3
"the Plan"
means the plan numbered 1 annexed hereto

"the Grassed and Planted Areas"
means the grassed and planted areas which adjoin Home Farm Road Brighton East
Sussex

"the Demised Premises"
means the land with the building erected thereon or on some part thereof known 
as Unit 2 Home Farm Business Centre Home Farm Road Brighton East Sussex and the 
curtilage thereof as the same is shown edged red on the Plan and shall include 
any other building from time to time erected thereon or on some part thereof

"Unit 1"
means the property adjoining the Demised Premises known as Unit 1 Home Farm 
Business Centre Lewes Road Brighton aforesaid

"the Main Structure"
means the roof foundations floor structures load bearing walls or frame 
stanchions beams window frames external walls external drains pipes and other 
external services of the Demised Premises

"the Soakaways"
means the soakaways situated on the Demised Premises and drainage pipes leading 
thereto from Unit 1

"Insured Risks"
means (subject to such exclusions and limitations as are imposed by the 
Insurers and to the extent that insurance cover against any particular risk is 
ordinarily available with a reputable insurer for property such as the Demised 
Premises) subsidence landslip heave fire explosion storm tempest lightning 
aircraft (not being hostile aircraft) and articles dropped therefrom riot civil 
commotion and flood and such other insurable risks against which the Landlord 
shall reasonably deem it desirable or expedient to insure

                                      -2-
<PAGE>   4
                            [Schematic of property]
<PAGE>   5
     "Term"
     means 21 years commencing on 24th June 1995

     "The Rent Commencement Date"
     means 24th June 1996

     "the Initial Market Rent"
     means the sum of TWO HUNDRED AND EIGHTY FIVE THOUSAND POUNDS 
     (Pounds Sterling 285,000) per annum exclusive of Value Added Tax

     "the First Reserved Rent"
     means the yearly rent reserved by Clause 2(A)
     hereof

     "the Secondly Reserved Rents"
     means

     (1)  a sum representing the cost reasonably and properly incurred or a fair
          proportion thereof (subject to the provisions of Clause 4(7)(h)
          hereof) of complying with the Landlord's insuring covenant hereinafter
          contained

     (2)  all other sums payable by the Tenant under the covenants on the part
          of the Tenant contained in this lease

     (3)  any interest chargeable under the provisions of this lease

     (4)  any additional insurance premiums payable by the Tenant arising under
          the provisions of Clause 4(7) of this lease

     (5)  all expenses costs fees and other sums incurred under the provisions
          Clause 4(24) hereof

     "the Review Dates"
     means 24th June 2001 24th June 2006 and 24th June 2011

                                      -3-

<PAGE>   6
     "the Review Period"      
     means the period starting with any Review Date up to and including the day
     immediately preceding the next Review Date or starting with the last Review
     Date up to the end of the Term

     "the Landlord's Surveyor"
     means any person or firm of surveyors appointed by or acting for the
     Landlord including an employee of the Landlord to perform the function of a
     Surveyor for any purposes under this lease

     "the Service Charge" 
     means the sums payable by the Tenant in accordance with Part 2 of the Third
     Schedule hereto

     "the Service Charge Year"
     means the period of twelve months up to the 31st March each year or such
     other period as the Landlord shall from time to time choose

     "the Service Costs"
     means all costs expenses and outgoings whatsoever incurred by the Landlord
     in carrying out the works and providing the services set out in Part 1 of
     the Third Schedule hereto

     "the Superior Lease"
     means the lease of the Demised Premises and other land date 5th May 1991
     and made between the Brighton Borough Council of the one part and the
     Landlord of the other part

     "the Superior Landlord"
     means Brighton Borough Council or such other person entitled to the benefit
     of the reversion expectant upon the determination of the Head Lease

     "the Electricity Sub-Station Lease"
     means the electricity sub-station lease dated 20th June 1991 and made

                                      -4-
<PAGE>   7

     between the Superior Landlord of the one part and Seeboard PLC of the other
     part

     "the Interest Rate"
     means the rate of four per centum per annum above the base rate from time
     to time of The Royal Bank of Scotland PLC

     "the Planning Acts"
     means the Town and Country Planning Act 1990 the Planning (Consequential
     Provisions) Act 1990 the Planning (Hazardous Substances) Act 1990 and the
     Planning (Listed Building and Conservation Areas) Act 1990 or any statutory
     consolidation modification or re-enactment of all or any of the above Acts

     "the Units"
     means all the units lettered "A" "B" "C" and "D" on the Plan together with
     the forecourt parking and landscaped areas therewith

     "an Individual Unit"
     means any one of the Units

     "Qualifying Person"
     means a company or corporation registered in the United Kingdom which has
     annual profits (which term shall have a meaning which is consistent with
     the term "profits for the financial year" where used in the Fourth Schedule
     to the Companies Act 1985) in the United Kingdom as shown in such company's
     or corporation's properly audited financial statements for the last three
     12 month accounting periods immediately preceding the proposed assignment
     of this lease to such company or corporation (the last of such accounting
     periods expiring not more than 12 months prior to the date of such
     assignment) which are not less than the sum of the annual rents payable
     pursuant to Clauses 2(A) and 2(B) of this lease for the year immediately
     prior to the date of such assignment multiplied by a factor of 2.5

                                      -5-
<PAGE>   8
2.   IN consideration of the rents and tenants covenants hereinafter reserved
     and contained the Landlord HEREBY DEMISES unto the Tenant the Demised
     Premises TOGETHER WITH the easements and rights specified in Part 1 of
     the First Schedule hereto EXCEPT AND RESERVED unto the Landlord and
     others the easements and rights specified in Part 2 of the First Schedule
     hereto TO HOLD the same unto the Tenant for the Term SUBJECT TO and where
     appropriate with the benefit of the provisions of the Electricity
     Sub-Station Lease in so far as the same affect or benefit the Demised
     Premises YIELDING AND PAYING to the Landlord without deduction during the
     Term and proportionately for any fraction of a year the rents set out
     hereunder

     (A)  The FIRST RESERVED RENT as hereinbefore defined being

          (1)  from the date hereof until the Rent Commencement Date a
               peppercorn (if demanded): and

          (2)  from and including the Rent Commencement Date until and including
               the 24th December 2003 the Initial Market Rent: and

          (3)  from and including the 25th December 2003 until and including the
               23rd June 2006 the yearly rent agreed or determined at 24th June
               2001 in accordance with Clause 3 hereof or THREE HUNDRED AND
               SIXTY EIGHT THOUSAND POUNDS (Pounds Sterling 368,000) per annum
               exclusive of Value Added Tax whichever shall be the greater; and

          (4)  during each successive Review Period commencing with the Review
               Period that commences on the second Review Date (that is 24th
               June 2006) a rent equal to the yearly rent previously payable
               hereunder or such increased rent as shall be ascertained in
               accordance with Clause 3 hereof whichever shall be the greater

                                      -6-

<PAGE>   9
     ALL such rents to be paid by equal quarterly instalments in advance
     on the usual quarter days in every year the first payment of the
     Initial Market Rent (apportioned in respect of the period from 
     and including the Rent Commencement Date up to and including the day 
     immediately preceding the next following quarter day) to be payable 
     on the Rent Commencement Date

     (B)  The SECONDLY RESERVED RENTS are hereinbefore defined

          Such rents to be payable from and including the date hereof or (if
          earlier) the date of occupation (as determined by the Landlord or the
          Landlord's Surveyor) and to be paid to the Landlord within fourteen
          days of demand (except as otherwise provided)

3.   RENT REVIEW

     (1)  The increased rent for any Review Period shall be (having regard to
          current open market values) the best yearly rent at which the whole of
          the Demised Premises might reasonably be expected to be let at the
          relevant Review Date

          (a)  On the following assumptions at the relevant Review Date:-

               (i)   that the Demised Premises are fit for immediate occupation
                     and use and that no work has been carried out thereon by
                     the Tenant its undertenants or their respective
                     predecessors in title during the Term which has diminished
                     the rental value of the Demised Premises and that in case
                     the Demised Premises have been destroyed or damaged they
                     have been fully restored

               (ii)  that the Demised Premises are available to let in the open
                     market by a willing landlord to a willing tenant as a whole
                     without a premium but

                                      -7-


<PAGE>   10
                     with vacant possession and subject to the provisions of 
                     this lease (other than the amount of the rent hereby 
                     reserved but including the provisions for rent review) 
                     for a term of fifteen years from the relevant Review 
                     Date or the residue then unexpired of the term of this 
                     lease (whichever shall be the longer)

               (iii) that the covenants herein contained on the part of the
                     Tenant and the Landlord have been fully performed and
                     observed

          (b)  But disregarding:-

               (i)   any effect on rent of the fact that the Tenant its
                     undertenants or their respective predecessors in title have
                     been in occupation of the Demised Premises and

               (ii)  any goodwill attached to the Demised Premises by reason of
                     the carrying on thereat of the business of the Tenant its
                     undertenants or their respective predecessors in title in
                     their respective businesses and

               (iii) any increase in rental value of the Demised Premises
                     attributable to the existence at the relevant Review Date
                     of any improvement to the Demised Premises or any part
                     thereof carried out with consent where required by and at
                     the expense of the Tenant its undertenants or their
                     respective predecessors in title during the Term otherwise
                     than in pursuance of an obligation to the Landlord or its
                     predecessors in title and 

                                      -8-
<PAGE>   11
               (iv)  any effect on rental value of any obligation of the Tenant
                     to remove alterations or to restore or reinstate the
                     Demised Premises and

               (v)   any rent free period or reduced rent period allowed to the
                     Tenant under the terms of this lease and

               (vi)  the provisions of Clause 6 (4) (b) (c) and (d) hereof

     (2)  The increased rent for any Review Period may be agreed at any time
          between the Landlord and the Tenant or (in the absence of agreement)
          determined not earlier that the relevant Review Date by an arbitrator
          such arbitrator to be nominated in the absence of agreement by or on
          behalf of the President for the time being of the Royal Institution of
          Chartered Surveyors on the application of the Landlord or the Tenant
          made not earlier than six months before the relevant Review Date

     (3)  IT IS HEREBY FURTHER PROVIDED in relation to the ascertainment and
          payment of the reviewed rent as follows:-

          (a)  The arbitrator shall be a Chartered Surveyor having not less than
               ten years experience in letting and valuation of similar property
               and of similar sized properties to the Demised Premises
               throughout England

          (b)  The arbitration shall be conducted in accordance with the
               Arbitration Acts 1950 and 1979 and any statutory modification or
               re-enactment thereof for the time being in force with the further
               provision that if the arbitrator nominated pursuant to Clause 3
               shall die or decline to act the President for the time being of
               the Royal Institution of Chartered Surveyors or the person
               acting on his behalf may on the application of either the
               Landlord or the Tenant by writing discharge the arbitrator and
               appoint another in his place

                                      -9-
<PAGE>   12
          (c)  When the increased rent has been ascertained as hereinbefore
               provided the Landlord and the Tenant shall record it forthwith by
               each signing and exchanging a separate written memorandum and the
               Landlord and the Tenant shall bear their own costs in respect
               thereof

          (d)  (i)  if the increased rent payable on and from any Review Date
                    has not been agreed by that Review Date rent shall continue
                    to be payable at the rate previously payable and forthwith
                    upon the increased rent being ascertained the Tenant shall
                    pay to the Landlord any shortfall between the rent actually
                    paid and the increased rent payable from the relevant Review
                    Date (or in the case of the first review payable from 25th
                    December 2003) up to the quarter day immediately following
                    the date that the increased rent is ascertained together
                    with interest on each instalment thereof from the date upon
                    which the same would have been payable if the increased rent
                    had been ascertained on the relevant Review Date (or in the
                    case of the first review had been ascertained on 25th
                    December 2003) to the date of actual payment thereof at the
                    rate of two per cent below the Interest Rate and the
                    interest so payable shall be recoverable in the same manner
                    as rent in arrear

               (ii) for the purposes of this proviso the increased rent shall be
                    deemed to have been ascertained on the date when the same
                    has been agreed between the Landlord and the Tenant or as
                    the case may be the date of the award of the arbitrator

          (e)  Time shall not be of the essence of this Rent Review clause

          (f)  If either the Landlord or the Tenant shall fail to pay any costs
               awarded against it in an arbitration under the provisions hereof
               within fourteen days of the same being 

                                      -10-
<PAGE>   13
               demanded by the arbitrator the other shall be entitled to pay the
               same and the amounts so paid shall be repaid by the party
               chargeable on demand

     (4)  Without prejudice to the provisions of this Clause if on any Review
          Date there shall be in force any enactment which shall relate to the
          control of rents and/or which shall restrict the Landlord's right to
          review the rent or recover any increased rent under this lease then
          the Landlord shall be entitled upon the termination or relaxation of
          such restriction to serve notice (hereinafter called "Interim Notice")
          upon the Tenant and from and after the date of the termination or
          relaxation of such restriction until the next Review Date for until
          the end of the Term) as the case may be the rent shall be increased to
          whichever is the higher of the rent agreed or determined in accordance
          with the provisions hereinbefore contained but at the date of service
          of the Interim Notice (or such lesser sum as may be permitted) or the
          rent payable immediately prior thereto and the provisions of this
          Clause shall apply accordingly with the substitution of the date of
          the termination or relaxation of such restriction for the relevant
          Review Date

4.  THE Tenant hereby covenants with the Landlord as follows:-

     (1)  TO PAY RENT AND INTEREST

          (a)  To pay the rents hereby reserved unto the Landlord throughout the
               Term and during a statutory continuation thereof at all times and
               in manner aforesaid without any deduction whatsoever except as
               authorised by any statutory enactment for the time being in force

          (b)  If any of the rents hereby reserved shall be due but unpaid for
               14 days to pay interest thereon (if demanded by the Landlord)
               calculated on a daily basis with three monthly rests from the due
               date until receipt by the Landlord at the Interest Rate (the
               Interest Rate shall apply before as well 

                                      -11-
<PAGE>   14
               as after and notwithstanding any judgement of the Court) Provided
               that this Clause 4(1)(c) shall not prejudice any other right or
               remedy in respect of such reserved rents

          (c)  If following the occurrence of any of the events referred to in
               Clause 6(1) hereof acceptance of any of the rents hereby reserved
               shall be reasonably refused by the Landlord but shall
               subsequently be accepted without prejudice to any other right or
               remedy of the Landlord to pay interest thereon (if demanded by
               the Landlord) calculated on a daily basis with three monthly
               rests from the due date until acceptance and receipt by the
               Landlord at the Interest Rate (the Interest Rate shall apply
               before as well as after and notwithstanding any judgement of the
               Court) Provided that this Clause 4(1)(d) shall not prejudice any
               other right or remedy in respect of such reserved rents

     (2)  TO PAY SERVICE CHARGE AND INSURANCE

          (a)  To pay the Service Charge in the manner set out in Part 2 of the
               Third Schedule hereto

          (b)  To pay on demand therefor the sum representing the cost (subject
               to the provisions of clause 4(7)(h) hereof) of complying with the
               Landlord's insuring covenant hereinafter contained

     (3)  TO PAY RATES AND TAXES

          To pay and discharge all existing and future rates taxes charges
          duties assessments and outgoings whatsoever whether parliamentary
          local or otherwise now or hereafter imposed or charged upon the
          Demised Premises or any part thereof or upon the owner or any occupier
          thereof or payable by either in respect thereof (excluding any payable
          by the Landlord in respect of receipt of rent or any other payment
          made by the Tenant under this lease (except any VAT payable on 
          rent or

                                      -12-
<PAGE>   15
          any other payment made by the Tenant under this lease) or on any
          disposition or dealing with or the ownership of the reversion of this
          lease) but including all charges in respect of water gas electricity
          and telecommunications used or consumed at the Demised Premises
          PROVIDED ALWAYS that the Tenant shall not agree or by default allow to
          be fixed the rateable value of the Demised Premises or any part
          thereof without the prior written consent of the Landlord such consent
          not to be unreasonably withheld

     (4)  TO REPAIR

          Well and substantially to repair cleanse maintain amend and keep in
          good and substantial repair the Demised Premises (including the Main
          Structure and all fixtures fittings plant machinery and apparatus
          belonging thereto) and all additions made thereto and the walls fences
          drains appurtenances and decorations thereof and to renew and replace
          the same from time to time insofar as the same may be or become beyond
          repair at any time during or at the expiration of the Term (howsoever
          determined) damage in all such cases from any of the Insured Risks
          excepted so long as the policy of insurance effected by the Landlord
          shall not have been vitiated or payment of any policy moneys refused
          in whole or in part by reason of any act neglect or default of the
          Tenant its undertenants or their respective servants agents or
          licensees

     (5)  TO PAINT AND DECORATE

          In every third year of the Term and also during the last year thereof
          (howsoever determined) to paint in a proper and workmanlike manner the
          outside wood iron and other parts heretofore or usually painted of the
          buildings on the Demised Premises and all additions thereto with two
          coats of good quality paint suitable for external use and for the
          surface and material to which it is to be applied such painting in the
          last year of the Term (howsoever determined) to be in colours
          previously approved in writing by the Landlord and in every fifth year
          of the Term and also in the last year thereof (howsoever determined)

                                      -13-
<PAGE>   16
          to paint in a proper and workmanlike manner all the inside wood iron
          and other parts heretofore or usually painted of the buildings on the
          Demised Premises and all additions thereto with two coats of good
          quality paint suitable for the surface and material to which it is to
          be applied such painting in the last year of the Term (howsoever
          determined) to be in colours previously approved in writing by the
          Landlord and on the occasion of every such external painting to
          varnish or colour the external parts usually or previously so dealt
          with and on the occasion of every internal painting to varnish wash
          stop whiten and colour all such parts as have previously been or are
          usually so dealt with and to repaper with suitable paper of good
          quality (in the last year of the Term (howsoever determined) in
          colours previously approved in writing by the Landlord the parts
          previously or usually papered

     (6)  TO CLEAN WINDOWS ETC

          To clean internally and externally the windows of the Demised Premises
          as often as occasion shall require and at least once in every month
          and at least once a week to remove all refuse rubbish and scrap which
          may have accumulated on the Demised Premises

     (7)  INSURANCE

          (a)  Subject to the Landlord having supplied to the Tenant in writing
               full particulars of any policy of insurance effected on the
               Demised Premises and any modification or variation thereof not to
               do or omit or allow to be done or omitted any act matter or thing
               whatsoever whereby any policy of insurance effected on the
               Demised Premises or anything therein or on any adjoining or
               neighbouring premises of the Landlord may become void or voidable
               or the premiums payable for such insurance increased

          (b)  To the extent that any insurance premium payable in respect of
               any adjoining or neighbouring premises is increased by any 

                                      -14-
<PAGE>   17
               use act neglect omission or default of the Tenant its
               undertenants or their respective servants agents or licensees in
               relation to the Demised Premises to pay the Landlord on demand
               the amount of such increase

          (c)  In the event of the Demised Premises or any part thereof being
               destroyed or damaged by any of the Insured Risks to give
               immediate notice thereof in writing to the Landlord

          (d)  In the event of the Demised Premises or any part thereof being
               destroyed or damaged by any of the Insured Risks and the
               insurance money under any insurance effected against the same
               being wholly or partly irrecoverable (by reason of any act
               neglect omission or default of the Tenant its undertenants or
               their respective servants agents or licensees) then and in every
               such case the Tenant will pay to the Landlord forthwith the whole
               or (as the case may require) a fair proportion of the cost of
               completely rebuilding and reinstating the same

          (e)  Subject to the Landlord having supplied in writing to the Tenant
               full particulars thereof to comply with the requirements and
               recommendations of the Landlord's insurers

          (f)  Not to store on the Demised Premises any inflammable or any
               explosive combustible or deleterious substance save that the
               Tenant may store at the Demised Premises such reasonable
               quantities of inflammable substances in proper and safe
               containers as are normally used for its business SUBJECT TO the
               Tenant obtaining the Landlord's insurers prior written approval
               thereto and the Tenant paying any increase in insurance premium
               arising therefrom and on the reasonable request of the Landlord
               supplying to the Landlord details of the type and amounts of the
               substances stored on the Demised Premises

                                      -15-
<PAGE>   18
          (g)  To repay to the Landlord on demand the proper costs and expenses
               incurred in obtaining valuations of the Demised Premises for
               insurance purposes from time to time but so that such valuations
               shall not be carried out more frequently than once every three
               years

          (h)  The Landlord may retain for its own benefit any commissions or
               discount received or obtained by the Landlord on or based on the
               gross premiums and other expenses which would otherwise by paid
               incurred or suffered by the Landlord in effecting or maintaining
               such insurance

          (i)  To insure the keep insured in the joint names of the Landlord and
               the Tenant and such other names as the Landlord may reasonably
               require all the plate glass or any substitute or alternative
               material used in windows (if any) and doors in the Demised
               Premises against breakage or damage howsoever caused with an
               insurance company of repute to the full reinstatement value
               thereof the public liability relevant to such breakage and pay
               all premiums necessary for that purpose and whenever required
               produce to the Landlord or its agent the policy of insurance and
               the receipt for the current year's premium and whenever a claim
               arises to use the insurance money forthwith in reinstating the
               same with a like material to the reasonable satisfaction of the
               Landlord's Surveyor making up any deficiency out of the Tenant's
               own moneys

          (j)  To pay to the Landlord on demand the amount of any excess which
               may be applicable in the event of any claim in respect of any of
               the Insured Risks

     (8)  TO EXECUTE WORKS

          To execute all works on or in respect of the Demised Premises now or
          from time to time throughout the Term lawfully required to be 
          executed 

                                      -16-
<PAGE>   19

          by any local or public authority (including works required under the
          Health & Safety at Work ect. Act 1974 the Offices Shops and Railway
          Premises Act 1963 or any Act amending or replacing the same for the
          time being in force whether the said works shall be required to be
          executed by the Landlord or by the Tenant and in all respects and at
          the Tenant's own expense to comply with and cause to be complied with
          the provisions of all statutes byelaws and regulations for the time
          being in force and the requirements of any competent authority
          affecting or relating to the Demised Premises or the use thereof and
          at all times to indemnify and to keep indemnified the Landlord and the
          Superior Landlord against all claims demands expenses and liability in
          respect thereof

     (9)  NOTICES RECEIVED

          Within seven days of receipt of the same to give full particulars to
          the Landlord of any notice direction or order or proposal for a notice
          direction or order made given or issued to the Tenant by any
          government department or local or public authority and if so required
          by the Landlord to produce and supply copies of the same to the
          Landlord AND without delay to take all necessary steps to comply with
          the same AND ALSO at the request of the Landlord to make or join with
          the Landlord in making such objections or representations relating to
          the same as the Landlord shall deem expedient but with due regard
          being had to the Tenant's interest in the Demised Premises

     (10) TO PERMIT ENTRY TO VIEW

          To permit the Landlord and the Superior landlord and their respective
          surveyors or other agents during the Term at reasonable hours in the
          daytime on prior appointment to enter the Demised Premises to view the
          state of repair and condition of the same and to take inventories of
          the fixtures therein

     (11) TO PERMIT ENTRY TO REPAIR

                                      -17-
<PAGE>   20
          To permit the Landlord and the Superior Landlord or their respective
          agents or the Landlord's Surveyor with or without workmen at any time
          during the Term at reasonable hours in the daytime on prior
          appointment except in the case of emergency to enter upon the Demised
          Premises for the purpose of executing repairs or alterations to or in
          connection with any adjoining premises of the Landlord and the
          Superior Landlord the Landlord or the Superior Landlord making good
          all damage thereby occasioned to the Demised Premises

     (12) TO REPAIR ON NOTICE

          To repair and make good to the satisfaction of the Landlord and the
          Superior Landlord all breaches of covenant defects and wants of
          reparation for which the Tenant may be liable under the covenants
          herein contained of which notice shall have been given by the landlord
          to the Tenant within two calendar months after the giving of such
          notice or sooner if requisite

     (13) TO COMPLY WITH STATUTORY REQUIREMENTS

          (a)  At all times to observe and comply with the provisions of or
               imposed under any statute licence or regulation regulating or
               permitting the use of the Demised Premises for the purpose for
               which they are for the time being used and the requirements of
               any competent authority in that connection and at the expense of
               the Tenant to do all that is necessary to obtain maintain and
               renew all licences and registrations required by law for the use
               of the Demised Premises for that purpose

          (b)  At the sole cost of the Tenant to comply with the Planning Acts
               for the time being in force and with all byelaws orders and
               regulations licences consents permissions and conditions made
               thereunder affecting the Demised Premises or any use thereof and
               to indemnify and keep harmless and indemnified the Landlord
               against any breach or non-performance of any

                                      -18-
<PAGE>   21
               such requirements and against all costs expenses penalties and
               levies thereby arising

     (14) PLANNING

          In relation to the Planning Acts:-

          (a)  Not without the prior written consent of the Landlord such
               consent not to be unreasonably withheld or delayed to apply for
               permission to carry out on the Demised Premises any development
               requiring permission under the Planning Acts

          (b)  Not to implement any planning permission relating to the Demised
               Premises without the prior written consent of the Landlord such
               consent not to be unreasonably withheld or delayed but without
               prejudice to the generality of the foregoing such consent shall
               be given if in the opinion of the Landlord or the Landlord's
               Surveyor (whose decision shall be final) the value of the
               Landlord's reversionary interest is not affected thereby

          (c)  Whenever required to permit the Landlord to enter upon the
               Demised Premises to comply with any requirement lawfully made of
               it under the Planning Acts by any competent authority
               notwithstanding that any action reasonably necessary for
               compliance interferes with the Tenant's enjoyment of the Demised
               Premises

          (d)  To pay and satisfy any charge which may hereafter be imposed
               under the Planning Acts in respect of the carrying out of any
               operations or the institution or continuance of the use of the
               Demised Premises

          (e)  Unless the Landlord shall otherwise direct in writing to carry
               out and complete before the expiration or sooner determination of
               the Term any works stipulated to be carried 

                                      -19-
<PAGE>   22
               out to the Demised Premises (notwithstanding that such works are
               to be carried out by a later date) as a condition of planning
               permission for any development begun before such expiration or
               sooner determination

          (f)  If the Tenant shall receive any compensation relating to the
               Tenant's interest hereunder due to any restriction placed upon
               the user of the Demised Premises as a result of the Planning Acts
               then if and when the Tenant's interest hereunder shall be
               determined by assignment or under the power of re-entry herein
               contained the Tenant shall forthwith make such provision as is
               just and equitable for the Landlord to receive its due benefit
               from such compensation

     (15) PERMITTED USE

          Not to use or permit or suffer to be used the Demised Premises or any
          part thereof otherwise than solely and exclusively as and for use
          within Classes B1(b) or (c) or B2 of the Town and Country Planning
          (Use Classes) Order 1987 as originally enacted and uses ancillary
          thereto

     (16) PROHIBITED USES

          Not to use the Demised Premises or any part thereof nor allow the same
          to be used as the premises of any public or local authority to which
          the public have access or for any public meeting exhibition or
          entertainment or for any illegal or immoral purpose or for the
          purposes of a club whether or not one where intoxicating liquor is
          supplied to members or their guests nor permit or suffer any sale by
          auction to be held on the Demised Premises or any part thereof or to
          sell serve or supply or permit or suffer to be sold served or supplied
          any intoxicating liquor thereon or therefrom (save that intoxicating
          liquor may be served to staff in any staff restaurant which is
          ancillary to the use permitted by Clause 4(15) hereof or play or use
          or allow to be played or used any sound-producing instrument or

                                      -20-
<PAGE>   23
          apparatus on the Demised Premises or any part thereof so as to be
          audible outside the Demised Premises nor permit the Demised Premises
          to be used as a sleeping place for any person and not to use the
          Demised Premises or any part thereof or permit or suffer the same to
          be used for the purpose of any betting transactions or for gaming with
          or between persons resorting to the Demised Premises and not to make
          or permit or suffer to be made any application for a Betting Office
          Licence or a Licence or registration under the Gaming Acts 1963 to
          1968 in respect of any part of the Demised Premises

     (17) NUISANCE

          Not to do or commit or permit or suffer to be done or committed upon
          the Demised Premises or any part thereof any act or thing which shall
          be a nuisance annoyance or disturbance to the Landlord or the Superior
          Landlord or to the owners lessees or occupiers for the time being of
          any adjoining or neighbouring property or to the neighbourhood

     (18) ALTERATIONS

          (a)  Not at any time during the Term to make any alteration or
               addition to the sprinkler system (if any) or to make any
               alterations to the Demised Premises which affect the operation of
               the sprinkler system (if any) without first obtaining the consent
               in writing of the Landlord such consent not to unreasonably
               withheld or delayed

          (b)  Not at any time during the Term to make any alteration or
               addition to the electrical installation of the Demised Premises
               save in accordance with the terms and conditions laid down by the
               Institution of Electrical Engineers and the Regulations of the
               Electrical Supply Authority

          (c)  Not at any time during the Term to erect set up or maintain or
               suffer to be erected set up or maintained on the Demised

                                      -21-
<PAGE>   24
               Premises or any part thereof any building shed or similar
               structure whether of a permanent or temporary character

          (d)  Not at any time during the Term to make any change to the
               external design or appearance of the building constructed on the
               Demised Premises

          (e)  Not to cut maim alter or injure or suffer to be cut maimed
               altered or injured the Main Structure nor make any external or
               internal alterations in the plan or elevation of the building on
               the Demised Premises or in any party or other wall nor alter or
               change any of the materials or architectural decorations of the
               said building nor make or maintain or suffer to be made or
               maintained any addition thereto either in height or projection
               save that if any such alternations as aforesaid are necessary
               because of a permitted underletting of an Individual Unit then
               the provisions of Clause 4(18)(g) hereof shall apply thereto
               mutatis mutandis

          (f)  Not at any time during the Term to overload the floors or
               ceilings or the Main Structure in any way which imposes a weight
               or strain in excess of that which the building on the Demised
               Premises is constructed to bear with due margin for safety or
               which will in any way strain or interfere with the Main Structure

          (g)  Not to make any nonstructural erection addition or alteration
               whatsoever to the Demised Premises (including to walls timbers
               wires pipes drains appurtenances fixtures or fittings thereof)
               without the previous consent in writing of the Landlord (which
               consent shall not be unreasonably withheld or delayed) such
               consents to be without prejudice nevertheless to the provisions
               of this Clause 4(18) and Clauses 4(13)(14) and (26) nor except
               in accordance with plans and specifications (with such additional
               copies thereof as the Landlord may reasonably required previously
               submitted to and 

                                      -22-
<PAGE>   25
               approved in writing by the Landlord nor carried out except to the
               satisfaction of its surveyor

          (h)  Nothing herein contained in this Clause 4(18) shall prevent the
               Tenant from installing or removing internal nonstructural
               demountable partitioning in the Demised Premises without the
               Landlord's consent provided such works do not adversely affect
               the services in the Demised Premises and the Tenant shall supply
               the Landlord with plans detailing the internal layout of the
               Demised Premises then current on demand by the Landlord

          (i)  Any alterations or additions carried out to the Demised Premises
               shall at the end or sooner determination of the Term be
               reinstated by the Tenant if requested in writing by the Landlord
               so to do

     (19) SIGNS

          (a)  Not without the previous written consent of the Landlord and the
               Superior Landlord (such consents not to be unreasonably withheld)
               to carry out or permit the painting or writing of any notice or
               advertisement whatsoever whether permanent or temporary on the
               glass of the windows or doors of the building on the Demised
               Premises or (except with the previous written consent of the
               Landlord and the Superior Landlord) the affixing or display of
               any bill notice doorplate sign or advertisement which projects
               over any street or land over which the public has access

          (b)  Without prejudice to the provisions of Clause 4(19)(a) not to
               exhibit put up or permit upon any part of the exterior of the
               building on the Demised Premises and the open areas thereof
               without the previous consent in writing of the Landlord and the
               Superior Landlord (such consents not to be unreasonably withheld
               or delayed) any bill notice sign or advertisement

                                      -23-

<PAGE>   26
               other than such as relate solely to the Tenant its undertenants
               or other occupier's business for the time being carried on at the
               Demised Premises PROVIDED and it is hereby declared that if any
               bill notice sign or advertisement displayed in or upon any part
               of the exterior of the building on the Demised Premises or in or
               upon any part of the interior of the building on the Demised
               Premises which is visible from outside the building on the
               Demised Premises shall in the reasonable opinion of the Landlord
               or the Superior Landlord be unsightly undesirable or
               objectionable then the same shall be removed by the Tenant within
               twenty-four hours after the receipt by the Tenant of notice
               requiring the Tenant so to do

     (20) ALIENATION ETC

          (a)  COMPLETE BAR ON CERTAIN DEALINGS

               Not to assign underlet or part with possession or part with or
               share occupation of the Demised Premises or any part thereof save
               as hereinafter provided

          (b)  SHARING OCCUPATION

               The Tenant may share occupation or possession of any part of the
               Demised Premises with any member of the group of companies (as
               defined in Section 42(1) of the Landlord and Tenant Act 1954) of
               which the Tenant is itself a member on the condition that:-

               (i)   no relationship of landlord and tenant is created between
                     the Tenant and any such company

               (ii)  the possession or occupation shall forthwith be determined
                     if the Tenant and the relevant member

                                      -24-
<PAGE>   27
                     shall cease for any reason whatsoever to be members of the
                     same group of companies

               (iii) On written request from the Landlord or its agents the
                     Tenant shall supply in writing to the Landlord or its
                     agents details of the identity of any company as aforesaid
                     let into occupation

          (c)  ASSIGNING THE WHOLE

               (i)  Not to assign the whole of the Demised Premises:-

                    (a)  without the Landlord's prior written consent such
                         consent not to be unreasonably withheld or delayed

                    (b)  except to an assignee who shall first have

                         (aa) entered into a direct covenant with the Landlord
                              to observe and perform the covenants and
                              conditions on the part of the Tenant contained in
                              this lease

                         (bb) if reasonably so required by the Landlord
                              procured a covenant with the Landlord by an
                              acceptable guarantor or guarantors in the terms
                              (mutatis mutandis) set out in the Second Schedule
                              hereto or in such other form as the Landlord may
                              reasonably require

               (ii) Subject to compliance with the provisions of clause
                    4(20)(c)(i) then upon and with effect from completion of a
                    lawful assignment of the whole of the Demised Premises by
                    the person at that time being the Tenant ("the Assignor") to
                    another ("the Assignee") where either the 

                                      -25-
<PAGE>   28
                    Assignor is a Qualifying Person or the Assignee is a
                    Qualifying Person the Assignor shall cease to have any
                    liability for any future breach or non-observance or
                    non-performance of the covenants on the part of the Tenant
                    contained in this lease and any Surety of the Assignor shall
                    cease to have any liability for any future breach or
                    non-observance or non-performance of the covenants on the
                    part of the Tenant contained in this lease pursuant to any
                    covenants given in any guarantee or agreement between such
                    Surety and the Landlord PROVIDED ALWAYS

                    (a)  that the Assignor and any Surety of the Assignor shall
                         nevertheless remain liable in respect of any subsisting
                         breach of the said covenants occurring prior to the
                         date of the lawful assignment; and

                    (b)  that the Assignor and any Surety of the Assignor shall
                         enter into a Deed of Guarantee whereby the Assignor and
                         any Surety of the Assignor covenants with the Landlord
                         as surety (in a form reasonably acceptable to it)
                         incorporating a standard of obligations similar to
                         those set out in the Second Schedule hereto but adapted
                         to suit the circumstances in which the guarantee is
                         given for the period during which the Assignee remains
                         liable as Tenant under the terms of this lease

               (iii) If the Assignor and any Surety of the Assignor are not
                     released from their respective liabilities by the operation
                     of Clause 4(20)(c)(ii) because neither the Assignor or the
                     Assignee is a Qualifying Person, then the Assignor and any
                     Surety of the Assignor shall

                                      -26-
<PAGE>   29
                    in any event cease to have any liability for any future
                    breach or non-observance or non-performance of the covenants
                    on the part of the Tenant contained in this lease with
                    effect from the date of the first lawful assignment
                    thereafter by a person at that time being the Tenant to
                    another where either of those persons is a Qualifying Person

          (d)  UNDERLETTING THE WHOLE

               Not to underlet the whole of the Demised Premises:-

               (i)   without the Landlord's prior written consent such consent
                     not to be unreasonably withheld or delayed

               (ii)  except to an underlessee who shall first have

                     (a)  entered into a covenant with the Landlord to observe
                          and perform the covenants and conditions on the part
                          of the Tenant contained in this lease (other than the
                          covenant to pay rent) and

                     (b)  if reasonably so required by the Landlord procured a
                          covenant with the Landlord by an acceptable guarantor
                          or guarantors in the terms (mutatis mutandis) set out
                          in the Second Schedule hereto or in such other form as
                          the Landlord may reasonably require

               (iii) in consideration of any fine or premium

               (iv)  without reserving a yearly rent payable in advance on the
                     usual quarter days equal to the greater of

                                      -27-
<PAGE>   30
                    (a)  the then open market yearly rental value of the Demised
                         Premises and

                    (b)  the higher of the First Reserved Rent and the Initial
                         Market Rent

                    reviewable on the same dates and on the same terms (as set
                    out in Clause 3 hereof) as the First Reserved Rent

               (v)  except on similar covenants and conditions to those
                    contained in this lease and in particular:-

                    (a)  for the re-entry on breach of any covenant in the
                         underlease

                    (b)  that the underlease will contain similar terms as to
                         the carrying out of and the paying for repairs and
                         proper service charges

               (vi) without taking from any underlessee unqualified covenants
                    (which the Tenant shall enforce):-

                    (a)  not to assign or underlet the whole of the Demised
                         Premises without the prior written consent of the
                         Landlord (under this lease) such consent not to be
                         unreasonably withheld or delayed and

                    (b)  not to deal in any other way whatsoever with the
                         Demised Premises or any part thereof and

                    (c)  to obtain from any assignee of the underlease a
                         covenant with the Landlord 

                                      -28-

<PAGE>   31
                         (under this lease) to observe and perform the covenants
                         and conditions on the part of the Tenant contained in
                         this lease (other than the covenant to pay rent) during
                         the term granted by the underlease

          (e)  UNDERLETTING AN INDIVIDUAL UNIT

               Not to underlet an Individual Unit

               (a)  without the Landlord's prior written consent such consent
                    not to be unreasonably withheld or delayed

               (b)  without the Tenant erecting or procuring the erection of an
                    internal division wall or walls (as the case may be) between
                    the Individual Unit and the remaining Units details of which
                    having been supplied to the Landlord in accordance with
                    Clause 4(18)(g) hereof (and for the avoidance of doubt the
                    provisions of Clause 4(18)(g) hereof shall apply hereto) and
                    without the Tenant complying with all statutory requirements
                    insurers requirements and fire authority requirements or
                    recommendations in relation thereto

               (c)  except to an underlessee who shall first have

                    (aa) entered into a covenant with the Landlord to observe
                         and perform the covenants and conditions on the part of
                         the Tenant contained in this lease (other than the
                         covenant to pay rent and insofar as they are applicable
                         to the underletting of an Individual Unit) and

                    (bb) if reasonably so required by the Landlord procured a
                         covenant with the Landlord by an acceptable guarantor
                         or guarantors in the terms

                                      -29-
<PAGE>   32
                         (mutatis mutandis) set out in the Second Schedule
                         hereto or in such other form as the Landlord may
                         reasonably require

               (d)  in consideration of any fine or premium

               (e)  without reserving a yearly rent payable in advance on the
                    usual quarter days equal to the then open market yearly
                    rental value of the Individual Unit reviewable on the same
                    dates and on the same terms as set out in Clause 3 hereof

               (f)  except on similar covenants and conditions to those in this
                    lease (in so far as they are applicable to the underletting
                    of an Individual Unit) and in particular:-

                    (aa) for the re-entry on breach of any covenant in the
                         underlease

                    (bb) that the underlease will contain similar terms as to
                         the carrying out or paying for repairs and proper
                         services charges

               (g)  without taking from any underlessee unqualified covenants
                    (which the Tenant shall enforce):-

                    (aa) not to assign the underlet Individual Unit without the
                         prior written consent of the Landlord (under this
                         lease) such consent not to be unreasonably withheld or
                         delayed and

                    (bb) not to deal in any other way whatsoever with the
                         Demised Premises or any part thereof

                    (cc) to obtain from any assignee of the underlet Individual
                         Unit a covenant with the Landlord

                                      -30-
<PAGE>   33
                         (under this lease) to observe and perform the covenants
                         and conditions on the part of the Tenant contained in
                         this lease (other than the covenant to pay rent) during
                         the term granted by the underlease insofar as such
                         covenants and conditions relate to the underlet
                         Individual Unit

          (f)  RENT REVIEW UNDER UNDERLEASES

               To procure that in any underletting the yearly rent is reviewed
               under such underlease in accordance with the terms of the
               underlease but not to agree any rent on review under any
               underlease without the prior written consent of the Landlord such
               consent not to be unreasonably withheld and (if the rent under
               the underlease is to be awarded by an arbitrator in accordance
               with the provisions therein contained) to procure that the
               Landlord's representations as to the yearly rent payable
               thereunder are made to the arbitrator to the reasonable
               satisfaction of the Landlord

          (g)  ENFORCEMENT OF COVENANTS

               To enforce the performance and observance by every underlessee of
               the provisions of the underlease (whether of the whole of the
               Demised Premises or an Individual Unit) and not at any time
               either expressly or by implication to waive any breach of the
               covenants or conditions on the part of the underlessee or
               assignee of any underlease nor without the consent of the
               Landlord (such consent not to be unreasonably withheld) to vary
               the terms

          (h)  AGREEMENT

               It is hereby expressly agreed and declared that if the Landlord
               (acting reasonably) shall not be satisfied that the yearly rent
               to be reserved by a proposed underlease is in accordance with
               Clause 4(20)(d)(iv) or 4(20)(i)(e) (as the case may be) then the
               Landlord

                                      -31-
<PAGE>   34
               may refuse its consent to such underletting and such refusal
               shall be deemed to be reasonable

     (21) TO REGISTER ANY DISPOSITION

          To give notice in writing of every assignment assent transfer
          underlease change of name charge or devolution of or other instrument
          relating to or affecting the Demised Premises and to produce a
          certified copy of the same within twenty one days after the execution
          or grant thereof to the solicitors of the Landlord and to pay their
          reasonable registration fee (and that of the Superior Landlord) in
          respect of each such instrument PROVIDED THAT registration of any such
          document shall not require the Landlord to consider the terms thereof
          and shall not be evidence that it has done so

     (22) RE-LETTING

          To permit the Landlord and the Superior Landlord or their agents at
          any reasonable time to enter upon the Demised Premises and to affix
          upon any appropriate or suitable part thereof a notice board or boards
          for re-letting at any time six months prior to the expiration or
          sooner determination of the Term or at any time for selling and to
          permit all persons authorised by order in writing of the Landlord or
          its agents to view the Demised Premises at reasonable hours in the
          daytime without interruption

     (23) EASEMENTS

          To take all necessary steps to prevent any encroachment upon the
          Demised Premises or the acquisition of any new right to light passage
          drainage or other easement over upon or under the Demised Premises and
          to give notice in writing to the Landlord of any threatened
          encroachment or attempt to acquire any such easement and throughout
          the Term to preserve unobstructed and undefeated all rights of light
          and other easements appertaining to the Demised Premises and not to
          permit or suffer but give notice in writing to the Landlord of any 
          act

                                      -32-
<PAGE>   35
          matter or thing whereby a new easement or encroachment might come to
          be made into against over or upon the Demised Premises or any part
          thereof and to do all such things as the Landlord may reasonably
          require to prevent the same

     (24) LANDLORD'S COSTS

          To pay to the Landlord on an indemnity basis all reasonable and proper
          Solicitors' (as between a Solicitor and own client) Counsels'
          Surveyors' and other professional costs expenses and fees incurred by
          the Landlord

          (a)  In or in contemplation of any proceedings relating to the Demised
               Premises whether or not under Sections 146 or 147 of the Law of
               Property Act 1925 or the preparation and service of a notice
               thereunder (whether or not any right of re-entry or forfeiture
               has been waived by the Landlord or a notice served on the Tenant
               has been complied with or the Tenant has enjoyed relief under the
               provisions of the said Act or forfeiture is avoided otherwise
               than by relief granted by the Court) and to keep the Landlord
               fully and effectively indemnified against all costs expenses
               claims and demands whatsoever in respect of such proceedings

          (b)  In the preparation and service of a schedule of dilapidations at
               any time during or after the Term and in the inspection of the
               works which are the subject of such schedule whether during or
               after the carrying out thereof

          (c)  In connection with the recovery of any arrears of the rents
               hereby reserved

          (d)  In respect of any application for consent or approval required by
               this Lease whether or not such consent is granted or such
               approval given

                                      -33-
<PAGE>   36
     (25) TO YIELD UP

          At the expiration or sooner determination of the Term quietly to yield
          up the Demised Premises and any additions thereto so repaired painted
          cleansed maintained amended kept renewed and replaced as aforesaid

     (26) THE SUPERIOR LEASE ETC

          At all times during the Term to observe and perform the obligations on
          the part of the Landlord contained in the Superior Lease (except the
          obligation to pay the premium and the obligations referred to in
          clause 2(4) thereof) and Clause 4(e) of the Electricity Sub-Station
          Lease insofar as the same relate to or affect the Demised Premises and
          to keep the Landlord fully and effectually indemnified against all
          actions proceedings damages costs expenses claims and demands
          whatsoever in respect of any breach thereof

     (27) VALUE ADDED TAX

          Whenever in this lease provision is made for the Tenant to pay any sum
          (including but without prejudice to the generality of the foregoing
          rent legal costs registration fees surveyors and other professional
          fees charges and expenses) on which Value Added Tax is payable or may
          at the election of the Landlord be payable (and provided that the
          Landlord does so elect) then the Tenant shall pay in addition to such
          sum Value Added Tax thereon at the rate appropriate at the time of
          supply Provided That where the Value Added Tax supply is to the Tenant
          the Landlord shall provide the Tenant with a VAT invoice addressed to
          and in favour of the Tenant and where the VAT supply is to the
          Landlord the Tenant shall pay to the Landlord only that part of the
          Value Added Tax which the Landlord is not entitled to recover

     (28) PIPES AND DRAINS

                                      -34-
<PAGE>   37
          Not to observe or permit the obstruction of any pipes including the
          drains serving the Demised Premises by oil grease hair or other
          deleterious matter but to keep all pipes and drains in or serving the
          Demised Premises thoroughly cleaned as often as may be necessary

5.   THE Landlord hereby covenants with the Tenant as follows:-

     (1)  QUIET ENJOYMENT

          The Tenant paying the rents hereby reserved and performing and
          observing the several covenants conditions and agreements herein
          contained and on the Tenant's part to be performed and observed may
          peaceably and quietly hold and enjoy the Demised Premises during the
          Term without any lawful interruption by the Landlord or any person
          rightfully claiming under or in trust for the Landlord

     (2)  THE SUPERIOR LEASE ETC

          To observe and perform the covenants on the part of the Landlord
          contained in:-

          (a)  the Superior Lease but only in so far as the Superior Landlord
               shall require the same to be observed and performed and except as
               they are by this lease expressly assumed by the Tenant and

          (b)  Clauses 4(b) to (d) inclusive of the Electricity Sub-Station
               Lease

     (3)  TO INSURE

          To insure or cause to be insured the Demised Premises and all
          Landlord's fixtures and fittings therein or thereon of an insurable
          nature (other than those which the Tenant or other tenants may be
          entitled to remove) excluding all the glass therein against (i) loss
          or damage by the Insured Risks in such sum (including any incidental

                                      -35-
<PAGE>   38
          expenses) as shall be determined from time to time by the Landlord to
          represent the reinstatement cost thereof as new together with all
          professional and other fees and expenses and the cost of site
          clearance and other incidental expenses (ii) public liability of the
          Landlord involving or relating to the Demised Premises or any part
          thereof and (iii) the loss of four years rent in some insurance office
          of repute and to supply a summary of such insurance and evidence of
          payment of the current premium to the Tenant on request once yearly
          and in the case of destruction or damage to the Demised Premises by
          any Insured Risk to immediately notify the insurer on receiving
          notification from the Tenant of the damage or destruction and to claim
          all sums due under the insurance policy and use all reasonable
          endeavours to procure the payment by the insurer of all sums properly
          due under the insurance policy and apply for and use all reasonable
          endeavours to obtain all planning permissions building regulations
          consents and other consents or licences necessary to enable the
          Landlord to reinstate the Demised Premises and (unless payment of any
          money payable under any policy of insurance shall be wholly or partly
          withheld or refused either in consequence of any exclusion or
          qualification imposed by insurers or of any act neglect or default of
          the Tenant its undertenants or their respective servants agents or
          licensees) to ensure that all insurance moneys (other than for loss of
          rent and public liability) received by the Landlord are with all
          convenient speed (subject to the necessary labour and materials being
          procurable and to all necessary statutory consents being obtained)
          laid out and applied in rebuilding repairing or otherwise reinstating
          the Demised Premises and to make up any deficiency out of its own
          monies

     (4)  INSURANCE PROCEEDS

          Subject to the provisions for reinstatement contained in Clause 5(3)
          hereof the building insurance proceeds shall belong to Landlord for
          its own use and benefit absolutely

     (5)  NOTIFICATION

                                      -36-
<PAGE>   39
          The Landlord will notify its insurers of the Tenant's interest in the
          Demised Premises and have it noted on the policy or policies of
          insurance

     PROVIDED ALWAYS that where any person comprising the Landlord assigns its
     interest in the reversion to the Demised Premises such person shall be
     released from the covenants set out above in this Clause 5 with effect from
     the date of such assignment

6.   PROVIDED ALWAYS and it is hereby agreed and declared as follows:-

     (1)  FORFEITURE AND RE-ENTRY

          That this lease is made upon the express condition that if (a) any of
          the rents hereby reserved shall be unpaid for twenty one days after
          the due dates whether the same shall have been lawfully demanded or
          not or (b) any Tenant's covenant shall not have been observed or
          performed or (c) if the Tenant being an individual or firm shall
          become bankrupt or be the subject of an interim order under Part VIII
          of the Insolvency Act 1986 or being a Company shall go into either
          compulsory or voluntary liquidation (except for the purpose of
          reconstruction or amalgamation) or shall have an administration order
          made in respect of it under the Insolvency Act 1986 or if an
          administrative receiver or a receiver shall be appointed or (d) the
          Tenant shall enter into composition or arrangement with creditors or
          shall suffer any distress or execution to be levied on the goods of
          the Tenant then and in any of the said cases and at any time
          thenceforth it shall be lawful for the Landlord or its authorised
          agent to re-enter into or upon the Demised Premises and to repossess
          and enjoy the same as if this lease had not been made but without
          prejudice to any right of action or remedy of either party in respect
          of any antecedent breach of any of the covenants by the other herein
          contained 

                                      -37-
<PAGE>   40
     (2)  RENT CESSER

          If during the Term the Demised Premises or any part thereof shall be
          destroyed or damaged by any Insured Risk so as to be unfit for
          occupation or use and the policy of insurance effected by the Landlord
          shall not have been vitiated or payment of the policy moneys wholly or
          partly withheld or refused by reason of any act neglect or default of
          the Tenant its undertenants or their respective servants agents or
          licensees the First Reserved Rent or a fair proportion thereof
          according to the nature and extent of the damage sustained shall be
          suspended until the Demised Premises shall again be fit for occupation
          and use or until the expiration of four years from the date of the
          damage or destruction whichever shall be the earlier and any dispute
          shall be referred to the award of a single arbitrator to be appointed
          in default of agreement upon the application of either party by the
          President for the time being of the Royal Institution of Chartered
          Surveyors in accordance with the provisions of the Arbitration Acts
          1950 and 1979 or any statutory modification thereof for the time being
          in force

     (3)  DETERMINATION BY EITHER PARTY

          If within four years from the date of such damage or destruction as
          aforesaid of the Demised Premises reinstatement or rebuilding of the
          Demised Premises has not been practically completed then after the
          expiration of the said four year period but only before such practical
          completion as aforesaid either party may give written notice to the
          other terminating this lease three months from the date of such notice
          and upon expiry of such notice this lease shall absolutely determine
          and the rights and obligations of the parties shall cease but without
          prejudice to any right or claim arising hereunder and still subsisting
          at the date of determination

                                      -38-
<PAGE>   41
     (4)  DETERMINING BY TENANT

          (a)  At any time before 25th November 2002 ECC Simulation Limited may
               serve a notice to terminate the Term on 24th December 2003 and if
               it does so and if ECC Simulation Limited delivers to the Landlord
               vacant possession of the Demised Premises by 12 noon on 24th
               December 2003 the Term will end at 12 noon on 24th December 2003
               (rent being paid for all that day) but the termination will not
               affect any claim by either party in respect of antecedent
               breaches of the provisions of this lease

          (b)  The provisions of Clause 6(4)(a) hereof shall be null and void if
               ECC Simulation Limited (with the consent of the Landlord) grants
               an underlease of the whole of the Demised Premises or an
               Individual Unit at any time before 24th December 2003 which does
               not comply with the provisions of Clause 6(4)(d) hereof save if
               the Landlord at its discretion releases the provisions of this
               Clause 6(4)(b) in the Licence to Underlet

          (c)  Notwithstanding the provisions of Clauses 4(20)(d) and (e) of
               this lease ECC Simulation Limited shall not underlet the whole of
               the Demised Premises nor an Individual Unit after a notice to
               terminate has been served by the Tenant pursuant to Clause
               6(4)(a) hereof
  
          (d)  The provisions of Clauses 6(4)(b) and (c) above shall not apply
               in circumstances where an underlease of the whole of the Demised
               Premises or an Individual Unit contains an agreement authorised
               by the Court excluding the provisions of Sections 24-28
               (inclusive) of the Landlord and Tenant Act 1954 and is for a term
               which expires on or before 12 noon on 24th December 2003

                                      -39-


   
<PAGE>   42
          (e)  For the avoidance of doubt the benefit of the rights referred to
               in Clause 6(4)(a) hereof are personal to ECC Simulation Limited

     (5)  NOTICES

          The provisions of Section 196 of the Law of Property Act 1925 as
          amended by the Recorded Delivery Service Act 1962 shall apply to all
          notices required to be served under this lease

     (6)  MORTGAGEES AND SUPERIOR LANDLORD

          In this lease the powers rights matters and discretions reserved to or
          exercisable by the Landlord including powers to enter inspect repair
          maintain or alter the Demised Premises or any part of the Landlord's
          adjoining premises shall also be reserved to or exercisable by its
          mortgagees and by the Superior Landlord and their respective
          mortgagees servants agents or workmen

     (7)  SUPERIOR LANDLORD'S CONSENT

          In this lease where the consent or approval of the Landlord is
          required under this lease the giving of such consent or approval
          (which shall not be unreasonably withheld) shall be conditional upon
          the consent or approval of the Superior Landlord being obtained so far
          as may be required and the Landlord shall at the request and cost of
          the Tenant use all reasonable endeavours to obtain any such consents
          or approvals whenever they may be so required

     (8)  DISPUTES

          Any dispute arising as between the Tenant and the lessee or occupier
          of any adjacent or neighbouring premises belonging to the Landlord as
          to any easement right or privilege enjoyed or used in common shall be
          decided by the Landlord or the Landlord's surveyor whose decision

                                      -40-
<PAGE>   43
          (save in the case of manifest error) shall be binding upon all parties
          to the dispute

     (9)  COMPENSATION ON VACATING

          (a)  Any statutory right of the Tenant to claim compensation from the
               Landlord on vacating the Demised Premises shall be excluded as
               far as law may allow

          (b)  The Tenant shall indemnify the Landlord against any compensation
               payable by the Landlord pursuant to statute to any person
               deriving title to the whole or any part of the Demised Premises
               through or under the Tenant upon that person quitting where such
               compensation would not have been payable by the Landlord if the
               person quitting had been the lessee under a lease granted by the
               Landlord containing a clause in the form of Clause 6(9)(a)

     (10) RIGHTS OF ENTRY

          Notwithstanding anything contained in this lease all rights of entry
          into the Demised Premises referred to in Part 2 of the First Schedule
          to this lease and Clauses 4(10) 4(11) 4(14)(c) and 4(22) of this lease
          shall only be exercised in the company of an escort provided by ECC
          Simulation Limited (except in the case of emergency) and ECC
          Simulation Limited undertakes to provide such escort without delay as
          and when required. The provisions of this Clause 6(10) shall only
          apply while ECC Simulation Limited remains the tenant of the Demised
          Premises

     (11) INTERPRETATION

          (a)  Whenever the Demised Premises are vested in more than one person
               for the Term every covenant on the part of the Tenant herein
               contained shall be deemed to be made jointly and severally by
               those persons

                                      -41-
<PAGE>   44
          (b)  Words importing the masculine gender shall include the feminine
               gender and words in the singular shall include the plural

          (c)  The clause headings hereto shall not affect in any way the
               construction of this lease

     (12) DELIVERY

          The provisions of this lease (other than those contained in this
          clause) shall have no effect until this lease has been dated

     (13) LAW AND JURISDICTION

          (a)  This lease and the rights and obligations of the parties hereto
               shall be governed by and construed in accordance with English law

          (b)  Any suit action or proceeding arising out of or relating to this
               lease and any action or proceedings to execute or otherwise
               enforce any judgment obtained against the Tenant or the Surety
               for breach of this lease may be instituted in the Courts of
               England and Wales and by executing this lease the Tenant and the
               Surety both unconditionally and irrevocably submit to such
               jurisdiction

7.  THE Surety hereby covenants with the Landlord as follows:-

     (1)  That the Tenant will throughout the Term and also during such period
          as the Tenant remains in occupation of the Demised Premises pay the
          rents hereby reserved on the days and in manner aforesaid and shall
          duly perform and observe all the covenants hereinbefore on the
          Tenant's part contained and that in the event of the Tenant failing to
          do so the Surety will indemnify and keep indemnified the Landlord from
          and against all actions claims demands costs losses and expenses

                                      -42-
<PAGE>   45
               which may be brought or made against or sustained or incurred by
               the Landlord howsoever arising directly or indirectly out of or
               in connection with such failure PROVIDED ALWAYS and it is hereby
               agreed that any neglect or forbearance of the Landlord in
               endeavouring to obtain payment of the several rents when the same
               become payable or to enforce performance or observance of the
               Tenant's covenants and any time which may be given by the
               Landlord to the Tenant shall not release or exonerate or in any
               way affect the liability of the Surety under this covenant

     (2)  That if for any reason the term hereby granted shall be prematurely
          determined by forfeiture or if the same shall be disclaimed in
          circumstances releasing the Tenant from liability the Surety will (if
          so required by the Landlord within 60 days of the date of such
          forfeiture or disclaimer) accept from the Landlord a grant of a new
          lease of the Demised Premises from the date of such determination or
          disclaimer for the residue of the Term then unexpired at the same
          several rents hereinbefore reserved and subject to the like covenants
          and provisos as are herein contained and at the expense of the Surety
          and on the execution of such further lease the Surety shall execute
          and deliver to the Landlord a counterpart thereof or (as the case may
          be) the Surety shall accept the vesting in it of this lease

     (3)  That if the Landlord shall not require the Surety to take a lease of
          the Demised Premises pursuant to Clause 7(2) above the Surety shall
          nevertheless upon demand pay to the Landlord a sum equal to the rent
          and to all other payments that would have been payable under this
          lease but for the disclaimer in respect of the period from the date of
          the said disclaimer until the expiration of six months therefrom or
          until the Demised Premises shall have been relet by the Landlord
          whichever shall first occur

     (4)  The Surety represents and warrants to the Landlord that the Surety has
          full power authority and legal right to enter into the covenants
          contained in this Clause 7

                                      -43-
<PAGE>   46
     (5)  The rights and obligations of the parties hereto shall be governed and
          construed in accordance with English law

     (6)  The Surety hereby irrevocably:-

          (a)  agrees that the Courts of England and Wales shall have
               jurisdiction to hear and determine any suit action or proceeding
               arising out of our relating to this lease (including this Clause
               7) and

          (b)  waives to the fullest extent permitted by law any objection which
               the Surety may now or hereafter have to the jurisdiction of the
               Courts of England and Wales to hear and determine any suit action
               or proceeding arising out of or relating to this lease (including
               this Clause 7) or any claim that any such Court is not a
               convenient or appropriate forum

     (7)  The submission to the jurisdiction of the Courts referred to in Clause
          7(6) shall not (and shall not be construed as to) limit the right of
          the Landlord to take proceedings against the Surety in any other Court
          of competent jurisdiction nor shall the taking of proceedings in any
          one or more jurisdictions preclude the taking of proceedings in any
          other jurisdiction whether concurrently or not

8.   AGREEMENT FOR LEASE

     It is hereby certified that there is no agreement for lease to which this
     lease gives effect

                                      -44-
<PAGE>   47
     IN WITNESS whereof the parties have executed this lease as a Deed the day
     and year first before written
 

                      THE FIRST SCHEDULE ABOVE REFERRED TO
                                     PART 1
                                TENANT'S RIGHTS

1.   A right during the Term to uninterrupted passage and running of water soil
     drainage gas electricity and telephone lines and other services (in common
     with the Landlord and the Superior Landlord and all other persons having
     the like rights) through the sewers pipes drains cables wires or other
     conducting media in the Landlord's and the Superior Landlord's property
     adjoining or neighbouring the Demised Premises all such rights to cease and
     determine as and when and to the extent from time to time that the said
     services shall become adopted and maintainable at public expense and the
     right to enter upon the said adjoining or neighbouring property of the
     Landlord and the Superior Landlord to make any necessary connections
     thereto or to cleanse repair and renew the same the person exercising such
     rights causing as little inconvenience as possible and making good any
     damage thereby caused to the property so entered
  
2.   With the Landlord's prior written consent and upon reasonable prior written
     notice given to the Landlord and all other persons affected thereby the
     right of access into an upon the adjacent premises of the Landlord as may
     be requisite to enable the Tenant to comply with the Tenant's obligations
     herein contained subject to causing as little inconvenience as possible and
     making good any damage caused

3.   The Right during the Term to exhibit the Tenant's name and business details
     in such manner as the Landlord shall reasonably decide on the name board
     sign erected by the Landlord at the junction of Home Farm Road with Lewes
     Road pursuant to the provisions of the Superior Lease

                                      -45-
<PAGE>   48
                                     PART 2
                               LANDLORD'S RIGHTS

1.   Unto the Landlord and the Superior Landlord and all persons now or
     hereafter entitled thereto the right of free and uninterrupted passage and
     running of water soil drainage gas electricity telephone lines and other
     services from and to any adjoining or neighbouring property by or through
     the sewers pipes drains cables wires conduits and ducts and other
     conducting media which are or may hereafter during the Term be in under or
     upon the Demised Premises and the right to use the Soakaways for the
     purposes of drainage of rainwater and surface water from Unit 1 but all
     such rights hereinbefore reserved shall cease and determine as and when and
     to the extent from time to time that the said services shall become adopted
     and maintainable at public expense

2.   Unto the Landlord and the Superior Landlord and their respective tenants
     the right at any time and from time to time hereafter to build upon and use
     any of their adjoining or neighbouring land and rebuild or alter any of the
     buildings now or hereafter to be erected thereon according to such plans
     (whether as to height extent or otherwise) and in such manner as they deem
     fit notwithstanding any interference thereby occasioned to the access of
     light and air to the Demised Premises or any buildings now or hereafter to
     be erected on the site thereof

3.   Unto the Landlord and the Superior Landlord all of the air over a level of
     two metres above the ridge level of the building now constructed on the
     Demised Premises as shown on the drawing numbered 2 annexed hereto such
     level to extend horizontally over the building and elsewhere over the site
     thereof and over a level of one metre above the level of the fence now
     erected along the rear boundary of the Demised Premises

                                      -46-
<PAGE>   49
4.   Unto the Landlord and (in addition in the case of the right reserved in
     paragraph (iii) below the Landlord's tenant or tenants of Unit 1 or the
     owner or occupier of Unit 1) all persons authorised by the Landlord the
     right at reasonable times and on reasonable notice (except in emergency) to
     enter the Demised Premises for the purposes of (i) inspecting the condition
     and state of repair thereof (ii) carrying out any works (whether of repair
     or otherwise) for which the Tenant is liable and which the Tenant has
     failed to carry out pursuant to Clause 4(4) and (8) hereof (iii) carrying
     out any works (whether of repair or otherwise) to any property adjoining
     the Demised Premises or to any party structure sewer drain or other thing
     used by the Tenant in common with others (including without prejudice to
     the generality of the foregoing the Soakaways) subject to making good any
     damage to the Demised Premises caused by such entry

5.   Unto the Landlord with or without workmen and others the right to enter
     upon the Demised Premises for the purpose of carrying out the works
     referred to in paragraph 5 of Part 1 of the Third Schedule hereto

                     THE SECOND SCHEDULE above referred to

1.   That the Tenant will throughout the Term and also during such period as the
     Tenant remains in occupation of the Demised Premises pay the rents hereby
     reserved on the days and in manner aforesaid and shall duly perform and
     observe all the covenants hereinbefore on the Tenant's part contained and
     that in the event of the Tenant failing to do so the Surety will indemnify
     and keep indemnified the Landlord from and against all actions claims
     demands costs losses and expenses which may be brought or made against or
     sustained or incurred by the Landlord howsoever arising directly or
     indirectly out of or in connection with such failure PROVIDED ALWAYS and it
     is hereby agreed that any neglect or forbearance of the Landlord in
     endeavouring to obtain payment of the several rents when the same become
     payable or to

                                      -47-
<PAGE>   50
     enforce performance or observance of the Tenant's covenants and any time
     which may be given by the Landlord to the Tenant shall not release or
     exonerate or in any way affect the liability of the Surety under this
     covenant

2.   That if for any reason the term hereby granted shall be prematurely
     determined by forfeiture or if the same shall be disclaimed in
     circumstances releasing the Tenant from liability the Surety will (if so
     required by the Landlord) accept from the Landlord a grant of a new lease
     of the Demised Premises from the date of such determination or disclaimer
     for the residue of the Term then unexpired at the same several rents
     hereinbefore reserved and subject to the like covenants and provisos as are
     herein contained and at the expense of the Surety and on the execution of
     such further lease the Surety shall execute and deliver to the Landlord a
     counterpart thereof or (as the case may be) the Surety shall accept the
     vesting in it of this lease

3.   That if the Landlord shall not require the Surety to take a lease of the
     Demised Premises pursuant to paragraph 2 above the Surety shall
     nevertheless upon demand pay to the Landlord a sum equal to the rent and to
     all other payments that would have been payable under this lease but for
     the disclaimer in respect of the period from the date of the said
     disclaimer until the expiration of six months therefrom or until the
     Demised Premises shall have been relet by the Landlord whichever shall 
     first occur

                      THE THIRD SCHEDULE above referred to
                                     PART 1
                                 Service Costs

1.   The repair maintenance and replacement from time to time of any drains
     pipes cables and wires or other conducting media under any property
     adjoining or neighbouring the Demised Premises until such time and to the
     extent that the drains pipes cables and wires or other conducting media
     shall become adopted and maintainable at public expense

                                      -48-
<PAGE>   51
2.   Discharging all rates taxes assessments duties and impositions payable in
     respect of the common parts of the adjoining or neighbouring property of
     the Landlord the use of which is shared by the Tenant with others

3.   Construction repairing rebuilding and cleansing all party walls and fences
     and also sewers drains pipes wires and other things the use of which is
     common to the Demised Premises and any other premises and the said name
     board referred to in paragraph 3 of Part I of the First Schedule

4.   Maintaining and repairing the Grassed and Planted Areas save for any part
     of that area which is demised to a tenant

5.   Maintaining and keeping the landscaped areas within the Demised Premises
     well and properly cultivated and trimmed and cut and free from weeds and in
     a tidy condition and to ensure that the said landscaped areas are fully
     planted out with appropriate plants and shrubs

6.   Providing such other services or carrying out any other work which the
     Landlord shall from time to time reasonably consider necessary for the
     benefit of the Demised Premises and any other premises on the Landlord's
     adjoining or neighbouring property

7.   Management of the Demised Premises and the adjoining or neighbouring
     property of the Landlord by the Landlord's surveyor the management fee of
     the Landlord's Surveyor not to exceed 12 1/2% of the total cost incurred by
     the Landlord for the provision of the services referred to in Part 1 of
     this Third Schedule hereto

                                     PART 2
                                SERVICE CHARGES

                                      -49-

<PAGE>   52
1.   The Service Charge to be paid by the Tenant shall be such fair proportion
     (which may if appropriate be the whole amount) of the actual or
     anticipated Service Costs for each Service Charge Year which shall be
     assessed by the Landlord's Surveyor according to a reasonable and proper
     basis for apportionment applicable from time to time to the Demised
     Premises and the rights hereby granted

2.   The Landlord may make and send to the Tenant notice in writing of the
     Landlord's estimate of the anticipated Service Costs and the Service Charge
     applicable to the Demised Premises for each Service Charge Year and the
     Tenant shall pay such estimate of the Service Charge by equal quarterly
     instalments in advance on the usual quarter days

3.   The Landlord will (unless prevented by causes beyond its control) prepare
     and send to the Tenant a detailed statement of the actual Service Costs and
     Service Charge for each Service Charge Year as soon as practicable after
     the end of such year and in the event of the Service Charge for the Demised
     Premises exceeding the aggregate amount paid by the Tenant for such year
     the Tenant will pay the balance due to the Landlord forthwith and in the
     event of the aggregate amount being greater the excess will be credited by
     the Landlord by way of set-off against the next instalment of Service
     Charge due from the Tenant

                                        THE COMMON SEAL of ECC SIMULATION
                                        LIMITED was hereunto affixed in the
                                        presence of:-

                                        Director:

                                        Signatory:

                                        THE COMMON SEAL of ECC  )
                                        INTERNATIONAL CORP. was )
                                        hereunto affixed in the )
                                        presence of:-           )


                                        President:

                                        Secretary:

                                       
                                      -50-