<PAGE>

                                                                   EXHIBIT 10.28

                             Dated March 28, 2001
                             --------------------



               (1)  THE EQUITABLE LIFE ASSURANCE SOCIETY


               (2)  VIRATA LIMITED


               (3)  VIRATA CORPORATION



                      -----------------------------------
                                     LEASE
                                      of
                        UNIT 230 CAMBRIDGE SCIENCE PARK
                                  MILTON ROAD
                                   CAMBRIDGE
                      -----------------------------------
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                                   CONTENTS


Clause    Heading

1.        INTERPRETATION...........................................   1

2.        DEMISE AND RENTS.........................................   6

3.        TENANT'S COVENANTS.......................................   7

4.        LANDLORD'S COVENANTS.....................................  30

5.        INSURANCE................................................  32

6.        RENT REVIEWS.............................................  34

7.        PROVISOS.................................................  39

8.        SERVICE CHARGE...........................................  44

9.        SURETY COVENANTS.........................................  46


          FIRST SCHEDULE
          The Demised Premise

          SECOND SCHEDULE
          Easements and other rights granted

          THIRD SCHEDULE
          Exceptions and Reservations

          FOURTH SCHEDULE
          Particulars of Landlord's services

          FIFTH SCHEDULE
          Deeds & Documents affecting the Demised Premises

          SIXTH SCHEDULE
          Surety Covenants
<PAGE>

THIS LEASE is made on                    March 28, 2001


BETWEEN:

(1)  THE EQUITABLE LIFE ASSURANCE SOCIETY (the "Landlord") (Company
     Registration Number 37038) whose registered office is at City Place House
     55 Basinghall Street London  EC2V 5DR; and

(2)  VIRATA LIMITED (the "Tenant") (Company Registration Number 2798338) whose
     registered office is at Mount Pleasant House Huntingdon Road Cambridge
     CB3 0BL; and

(3)  VIRATA CORPORATION (the "Surety") a company incorporated under the laws of
     the State of Delaware United States of America and having its principal
     place of business at 2933 Bunker Hill Lane Suite 201 Santa Clara California
     95054 United States of America and whose address for service in England and
     Wales is Mount Pleasant House Huntingdon Road Cambridge CB3 0BL



IT IS AGREED as follows:


1.   INTERPRETATION

1.1  In these presents except as otherwise provided or where the context
     otherwise requires the following words and expressions shall have the
     following meanings:

     the "Common Parts":  those parts of the Estate designed or intended for use
     in connection with the Estate by members of the public and/or for the joint
     use of any occupiers within the Estate and which shall include without
     prejudice to the generality of the foregoing all of the following namely
     all access roads unadopted roads courtyards malls service areas service
     roadways loading and unloading bays service ramp car parking bridges
     gardens pathways pavements pedestrian ways landscaped areas lifts plant
<PAGE>

     and machinery (if applicable) fire escape ways ramps signs noticeboards
     boundary walls service media fences gates storage areas refuse disposal and
     collection areas lakes water features and any other parts used in common
     with others

     the "Conduits":  all sewers drains mains pipes cisterns tanks meters
     gulleys culverts gutters conduits ducts flues watercourses channels subways
     wires cables sprinkler systems alarm and security systems and other
     conducting media of whatsoever nature

     the "costs of the Landlord's services":  the costs incurred by or on behalf
     of the Landlord in connection with the provision of the services and the
     other matters to or for the Demised Premises as specified in the Fourth
     Schedule

     the "Demised Premises":  the whole of the premises hereby demised as
     described in the First Schedule and all the appurtenances thereto belonging
     together with all additions alterations and improvements made thereto or
     reinstatement thereof at any time during the Term and shall also include
     all Landlord's fixtures and fittings which are now or at any time hereafter
     attached thereto any building now or hereafter erected on or in place of
     the premises hereby demised

     the "Estate":  that part of Cambridge Science Park Milton Road Cambridge as
     the same is shown for identification on Plan 1 and thereon edged blue

     the "Full Reinstatement Cost":  the costs to be incurred (including the
     Landlord's Architect's surveyor's and other professional fees and expenses
     incidental thereto and the cost of shoring up demolition and site clearance
     and similar expenses) in the Reinstatement of the Demised Premises in
     accordance with the requirements of this Lease at the time when such
     Reinstatement is likely to take place

     the "Insured Risks":  (subject to such exclusions and limitations as are
     imposed by the Insurers and notified to the Tenant in writing except in
     respect of the Irrigation System which at all times the Landlord shall use
     all reasonable endeavours to insure) the risks in respect of loss or damage
     by fire storm tempest flood  lightning civil commotion riot explosion
     (excluding the explosion of boilers not being domestic boilers) malicious
     damage aircraft and other aerial devices parts thereof and articles dropped
     therefrom (not being war damage within the meaning of the War Damage Act
     1943 or any modification

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     or re-enactment thereof or similar enactment for the time being in force)
     burst pipes the Irrigation System impact subsidence ground heave or
     landslip and such additional risks as the Landlord may from time to time
     deem prudent

     the "Insurers":  the Landlord's own insurance fund or the insurance office
     or underwriters of repute with whom the insurance cover taken out by the
     Landlord pursuant hereto is effected

     the "Irrigation System": the water tank on the roof of the Demised Premises
     and all pipes and other equipment associated therewith which tank and
     equipment do not serve the Demised Premises but belong to the Landlord for
     the purpose of irrigating the landscaping on the Estate or part thereof

     the "Landlord's Accounting Year":  the period from the 25th day of March to
     the 24th day of March in each year or such other annual period as the
     Landlord may in its absolute discretion determine from time to time

     the "Loss of Rent":  the loss of the Principal Rent for such period (not
     exceeding five years and not less than three years) as the Landlord may
     from time to time consider to be sufficient having regard to the likely
     period required for reinstatement in the event of either partial or total
     destruction (including an estimate for increased rent prior to a rent
     review)

     "Permitted Part": subject to the terms of the Superior Lease  the whole of
     a floor of the Demised Premises or one half of a floor of the Demised
     Premises  (excluding those parts of the floor affording access to or egress
     from the Permitted Part and excluding the service core) which shall have
     all necessary rights and easements as to be capable of beneficial
     occupation and use and "Permitted Parts" shall be construed accordingly

     "Personnel":  servants agents licensees and visitors and "Tenant's
     Personnel" includes any sub-tenant and the personnel of any sub-tenant or
     licensee of the Tenant

     "Plan 1": the plan for identification only annexed hereto and marked Plan 1

     "Plan 2": the plan for identification only annexed hereto and marked Plan 2

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     "Plan 3": the plan for identification only annexed hereto and marked Plan 3

     the "Planning Acts":  the Town and Country Planning Act 1990 the Planning
     (Listed Buildings and Conservation Areas) Act 1990 the Planning (Hazardous
     Substances) Act 1990 the Planning (Consequential Provisions) Act 1990 and
     the Planning and Compensation Act 1991 and any existing or future
     legislation of a similar nature

     the "Prescribed Rate":  the annual rate of interest which is from time to
     time 4% above the base rate for the time being of The Royal Bank of
     Scotland Plc (or such other Bank being a Member of the British Bankers
     Association as the Landlord may nominate by notice in writing to the
     Tenant) Provided that if it becomes impossible to ascertain such rate then
     the rate to be substituted for such base rate shall be such alternative and
     comparable rate of interest as the Landlord shall reasonably determine from
     time to time

     the "Principal Rent":  the rent first herein reserved

     "Reinstatement":  rebuilding and renovating the Demised Premises or the
     relevant part thereof in substantially the same form with such variations
     as may be required by law or by the appropriate regulatory bodies or by
     good building practice or which do not materially adversely affect the
     Tenant and the expression "Reinstate" shall be construed accordingly

     the "Rents":  all the rents reserved and made payable by the Tenant under
     this Lease

     the "Services":  gas electricity steam soil water telephone electrical
     impulses and other services

     the "Service Charge":  the proper proportion (to be determined from time to
     time by the Landlord or its surveyor whose decision shall be final and
     binding (save as to points of law and manifest error)) payable by the
     Tenant of the costs of the Landlord's services

     the "Superior Lease": the Lease dated 27 March 1990 (as varied by the Deed
     of Variation dated 5 November 1992) referred to in the Fifth Schedule



                                       4
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     the "Tenant's Covenants": all covenants obligations or stipulations
     conditions and agreements imposed upon the Tenant or on the part of the
     Tenant contained or implied by this Lease

     the "Term":  the term of years hereby created

     the "usual quarter days":  means 25th March  24th June  29th September and
     25th December in each year of the Term

     "Value Added Tax":  value added tax charged under the Value Added Tax Act
     1994 and shall include any interest fine penalty or surcharge in respect of
     value added tax charged save where the context otherwise requires

1.2  Where two or more persons are included in the expression the "Landlord" the
     "Tenant" or the "Surety" the covenants agreements and obligations hereby
     entered into by those persons shall be deemed to be entered into by them
     jointly and severally

1.3  the "Tenant": includes his her its or their successors in title and assigns
     and permitted undertenants and where two or more persons are included
     therein shall also include (as the case may be) the survivor or the
     survivors of those persons and shall also include the personal
     representatives of a sole individual or last surviving individual Tenant

1.4  the "Surety": includes his her its or their successors in title and where
     two or more persons are included therein shall also include (as the case
     may be) the survivor or the survivors of those persons and shall also
     include the personal representatives of a sole individual or last surviving
     individual Surety

1.5  the "Landlord": includes (where the context admits) the reversioner(s) for
     the time being expectant whether immediately or not upon the determination
     of the Term

1.6  this "Lease": includes any document which is supplemental hereto or which
     is entered into pursuant to or in accordance with the terms hereof

1.7  References to statutes statutory instruments bye-laws regulations orders
     and delegated legislation shall include any statute statutory instrument
     bye-law regulation order notice

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     direction or delegated legislation modifying re-enacting extending or made
     pursuant to or deriving effect from the same for the time being in force

1.8  Any covenant by the Tenant and/or the Surety not to do an act or thing
     shall be construed as if it were a covenant not to do or permit or suffer
     to be done such act or thing

1.9  Any covenant by the Tenant and/or the Surety not to omit to do an act or
     thing shall be construed as if it were a covenant not to omit or permit or
     suffer to be omitted or permitted such act or thing

1.10 Any reference to any act of the Tenant and/or the Surety shall include any
     act neglect default or omission of the Tenant and/or the Surety or the
     Tenant's Personnel

1.11 Headings appearing in this Lease are for ease of reference only and shall
     not affect the construction of this Lease

1.12 References in this Lease to Clauses sub-clauses Paragraphs sub-paragraphs
     and Schedules are references to those contained in this Lease


2.   DEMISE AND RENTS

     In consideration of the rents hereinafter reserved and of the covenants on
     the part of the Tenant hereinafter contained the Landlord hereby demises
     unto the Tenant all those the Demised Premises together with the easements
     and rights (but not including any right or easement unless the same be
     expressly herein referred to) specified in the Second Schedule but except
     and reserving unto the Landlord and all other persons authorised by the
     Landlord the easements and rights and other matters specified in the Third
     Schedule to hold the same unto the Tenant for a term of years from the 26th
     day of February 2001 until the 24th day of March 2001 and thereafter for a
     term of TWENTY YEARS from and including the 25th day of March 2001 SUBJECT
     to the covenants conditions stipulations exceptions reservations easements
     and other matters referred to or contained in the documents referred to in
     the Fifth Schedule and subject also to all rights and easements quasi-
     easements or reputed easements and privileges belonging to or enjoyed by
     any adjacent or neighbouring property which may be necessary or convenient
     for the

                                       6
<PAGE>

     enjoyment thereof yielding and paying therefor during the Term and
     proportionately for any fraction of a year in each case without any
     deduction whatsoever) the rents following that is to say FIRST from and
     including the 26th day of February 2001 the clear yearly rent of SEVEN
     HUNDRED AND THIRTY ONE THOUSAND FOUR HUNDRED AND FORTY EIGHT POUNDS
     ((Pounds)731,448.00) per annum exclusive (subject to the provisions for
     review herein contained) to be paid in advance by equal quarterly payments
     on the usual quarter days in every year the first of such payments being
     the rent from and including the 26th day of February 2001 to the usual
     quarter day then next succeeding then to be made on the 26th day of
     February 2001 SECONDLY within seven days of a written demand the moneys
     referred to in Clause 3.2 THIRDLY within seven days of a written demand the
     moneys referred to in Clause 3.7 FOURTHLY the moneys referred to in Clause
     7 FIFTHLY within seven days of written demand all costs charges and
     expenses which the Landlord may from time to time incur in connection with
     or in procuring the remedying of any breach by the Tenant of any of the
     covenants on the part of the Tenant contained in this Lease and SIXTHLY
     within seven days of a written demand all costs incurred by the Landlord in
     complying with its covenant under Clause 5.1 and also in effecting or
     maintaining insurance in respect of the public liability of the Landlord
     arising out of or in connection with any matter involving or relating to
     the Demised Premises


3.   TENANT'S COVENANTS

     The Tenant at the request of the Surety to the intent that the obligation
     hereby created shall continue throughout the Term HEREBY COVENANTS with the
     Landlord as follows:

3.1  Rents: To pay the Rents in accordance with Clause 2 without any deductions
     and to pay the Principal Rent by banker's standing order to the Landlord's
     bank from time to time notified to the Tenant in writing

3.2  Interest on Overdue Moneys: If any of the Rents or any other sum of money
     payable to the Landlord by the Tenant under this Lease shall be due but
     unpaid to pay on demand

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<PAGE>

     to the Landlord interest thereon at the Prescribed Rate (which interest
     rate shall still apply after and notwithstanding any judgment of the Court)
     from the due date until payment such interest to be calculated at a daily
     rate PROVIDED THAT this sub-clause shall not prejudice any other right or
     remedy in respect of such money

3.3  Outgoings:

     (a)  to pay (or in the absence of direct assessment on the Demised Premises
          to repay to the Landlord a reasonable and proper proportion such
          proportion to be determined by the Landlord's surveyor (who shall act
          reasonably and whose decision shall be final and binding save in case
          of manifest error) all existing and future rates taxes duties charges
          assessments impositions and outgoings whatsoever (whether
          parliamentary parochial local or of any other description and whether
          or not of a capital or non-recurring nature or of a wholly novel
          character) which now are or may at any time hereafter during the Term
          be charged levied rated assessed or imposed upon or be payable in
          respect of the Demised Premises or upon the owner or occupier in
          respect thereof excluding any tax (other than Value Added Tax or any
          other tax duty or imposition which supplements or replaces Value Added
          Tax) assessable on the Landlord in respect of the Principal Rent and
          in respect of any disposal of any reversion immediately or mediately
          expectant on the Term or the grant of this Lease

     (b)  If the Demised Premises or any part thereof have not been occupied for
          a period of six months prior to the end or other determination of the
          Term to pay to the Landlord on demand a sum equal to any chargeable
          amount payable by the Landlord to the relevant charging authority
          pursuant to Section 44A and Section 45 of the Local Government and
          Finance Act 1988 as amended by the Local Government and Housing Act
          1989 which would not have been payable by the Landlord had the Demised
          Premises or such part for such period been occupied

3.4  Services:

     (a)  to pay upon demand and to indemnify the Landlord against all charges
          in respect of the Services supplied to or consumed in the Demised
          Premises and all charges

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<PAGE>

          for the hire of meters in respect thereof the Landlord having no
          responsibility for the supply of the Services to the Demised Premises
          nor for any sums that may become payable in respect thereof

     (b)  to observe and perform all regulations and requirements of the gas
          electricity water telephone and other competent authorities in respect
          of the Demised Premises and the Services supplied thereto

3.5  Repairs:

     (a)  from time to time and at all times during the Term (so that all work
          carried out shall be done to the reasonable satisfaction of the
          Landlord) well and substantially to repair maintain cleanse and keep
          in good and substantial repair and condition in every respect the
          whole of the Demised Premises and every part thereof (with the
          exception of the Irrigation System which for the purposes of this
          Clause is not to be considered as part of the Demised Premises or as a
          Landlord's fixture and fitting) in accordance with modern practice and
          as often as shall be necessary to renew reinstate or replace the
          Demised Premises or any part or parts thereof and without prejudice to
          the generality hereof to renew and replace all Landlord's fixtures and
          fittings forming part of the Demised Premises which may become in need
          of renewal and replacement with fixtures plant equipment or machinery
          of a similar kind and no lesser quality (damage by any of the Insured
          Risks excepted if and so long as the policy or policies of insurance
          shall not have been vitiated or payment of any of the policy moneys
          withheld or refused by reason of any act neglect or default of the
          Tenant or any sub-tenant or their respective Personnel)

     (b)  without prejudice to the generality of Clause 3.5(a) to replace the
          ceiling tiles in the Demised Premises whenever reasonably necessary
          and in any case in the last three months of the Term (howsoever
          determined) with ceiling tiles of a similar kind and quality and of a
          design and colour approved by the Landlord (such approval not to be
          unreasonably withheld)

3.6  Decoration:

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     (a)  in the third year of the Term and in every succeeding third year of
          the Term and also during the last three months thereof (howsoever the
          same may be determined) to paint or treat (as appropriate) in a proper
          and workmanlike manner and in the case of paintwork with two coats at
          least of good quality paint of a colour which if different from the
          present colour shall be previously approved in writing by the Landlord
          (such approval not to be unreasonably withheld or delayed) all outside
          parts of the Demised Premises (save for the Irrigation System (if
          applicable)) previously or requiring to be painted and as often as the
          Landlord may reasonably consider necessary but in any event at least
          upon each occasion painting or treatment (as aforesaid) is required to
          be carried out to clean treat and wash in an appropriate manner to the
          reasonable satisfaction of the Landlord all materials surfaces and
          finishes of the exterior of the Demised Premises previously or
          requiring to be so cleaned treated and washed and in particular (but
          without prejudice to the generality of the foregoing) all soffits
          fascias window frames cladding panels doors and rainwater pipes

     (b)  in the fifth year of the Term and in every succeeding fifth year of
          the Term and during the last three months of the Term (howsoever the
          same may be determined) to paint all the internal surfaces previously
          or requiring to be painted and all additions thereto in the Demised
          Premises with two coats at least of good quality paint (which in the
          last year of the Term shall be in a colour previously approved in
          writing by the Landlord such approval not to be unreasonably withheld
          or delayed) and well and sufficiently to treat and decorate all the
          interior parts of the Demised Premises previously or requiring to be
          treated and decorated restoring and making good the Demised Premises
          in accordance with good standards of workmanship and materials
          available

3.7  Contribution to Joint Facilities: To pay a reasonable and proper proportion
     (to be determined by the Landlord's surveyor (acting reasonably) for the
     time being such determination to be final and binding on the parties hereto
     save as to points of law and in case of manifest error) of the expenses
     payable (including any proper management charges or a proper proportion of
     the cost of services if the Landlord undertakes the management in lieu of
     management charges) in respect of constructing repairing

                                       10
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     renewing cleansing maintaining providing improving and securing all (if
     any) party walls fences roads ways pavements courtyards service areas
     service bays car parking areas landscaped areas plant and machinery fire
     escape ways ramps signs and notice boards storage areas refuse disposal and
     collection areas land Conduits and all other things the use of which is
     common to the Demised Premises and to any adjoining or neighbouring
     premises insofar as the same are not included within the Service Charge
     herein provided for and to keep the Landlord indemnified against such
     proportion of such expense as aforesaid

3.8  Yielding Up:

     (a)  immediately prior to the expiration or sooner determination of the
          Term at the cost of the Tenant:

          (i)  to remove every moulding sign writing or painting of the name or
               business of the Tenant or other occupiers from the Demised
               Premises and to remove all tenants' fixtures and fittings
               furniture and effects from the Demised Premises making good to
               the reasonable satisfaction of the Landlord all damage caused by
               such removal and without prejudice to the generality of the
               foregoing to ensure that wherever such tenants' fixtures fittings
               plant or machinery are connected to or take supplies from any of
               the main Services they shall be disconnected in such a manner
               that all redundant Conduits are removed and sealed off at points
               as close as reasonably possible to the various ring mains or
               principal distribution pipes which provide the supplies such
               removal and sealing off to be carried out so as not to interfere
               with the continued function of the main services and to ensure
               that all walls main services and any other parts of the Demised
               Premises are made good after the removal of any such fixtures
               fittings plant or machinery to the reasonable satisfaction of the
               Landlord and to the satisfaction of the relevant authorities

          (ii) if so requested by the Landlord in writing no later than three
               months before the end of the Term (howsoever determined) to
               remove and make

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               good all alterations or additions made to the Demised Premises at
               any time during the Term and well and substantially to reinstate
               the Demised Premises (excluding the Irrigation System) in such
               manner as the Landlord shall direct and to its reasonable
               satisfaction

     (b)  at the expiration or sooner determination of the Term to give up all
          keys of the Demised Premises to the Landlord and quietly to yield up
          to the Landlord the Demised Premises with vacant possession in good
          and substantial repair and condition (with the exception of the
          Irrigation System) and in accordance with the covenants on the part of
          the Tenant herein contained together with all fixtures fittings
          improvements and additions which now are or may at any time hereafter
          be in or about the Demised Premises (but excepting tenants' fixtures
          and fittings which shall include carpets and floor boxes)

     (c)  to pay a sum equivalent to the loss of rents incurred by the Landlord
          during such period as is reasonably required for the carrying out of
          works after the end of the Term by reason of any breach of this Clause
          (but without prejudice to any other right of the Landlord) provided
          the breach results solely from the Tenant's actions and not from those
          of the Landlord its servants agents or licensees

3.9  Cleaning of Demised Premises:

     (a)  at all times during the Term to keep the Demised Premises in a clean
          and tidy condition and to employ only competent and respectable
          persons to carry out cleaning and at least once in every month during
          the Term properly to clean the insides and outsides of the windows and
          window frames of the Demised Premises and the entrance doors thereto

     (b)  to take all practicable steps to keep the Demised Premises free of
          vermin and pests

3.10 Entry by the Landlord and Others: To permit the Landlord and all persons
     authorised by it attended by a member of the Tenant's staff to enter the
     Demised Premises with all necessary materials and appliances at any
     reasonable time or times during the Term upon reasonable prior notice
     (being a minimum of twenty-four hours) (except in the case of an

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<PAGE>

     emergency when no notice shall be required and then at any time (without
     having to be attended by a member of the Tenant's staff)) for any lawful
     purpose and in particular but without prejudice to the generality of the
     foregoing:

     (a)  to take inventories of the fixtures and fittings therein; or

     (b)  to estimate the current value thereof for insurance purposes; or

     (c)  to exercise the rights hereinbefore excepted and reserved; or

     (d)  to ensure that nothing has been done or omitted to be done which
          constitutes a breach of any of the covenants herein and to remedy any
          such breach

     PROVIDED THAT the person so entering by virtue of sub-clauses (a) - (d)
     (inclusive) above shall cause as little inconvenience as possible and shall
     make good all physical damage caused thereby to the Demised Premises to the
     reasonable satisfaction of the Tenant but the Tenant shall not be entitled
     to any compensation as a result of such entry

3.11 Compliance with Notice to Repair: Forthwith in case of emergency but
     otherwise as soon as practicable to remedy repair and make good all
     breaches of covenant and any damage thereby caused and defects of which
     notice in writing shall have been given by the Landlord to the Tenant and
     for which the Tenant is liable under this Lease and within one month after
     service of such notice in the case of material defects and as soon as
     practicable in the case of other defects to commence and thereafter proceed
     diligently to remedy repair or make good any such defects or breaches AND
     if the Tenant shall make default in so doing it shall be lawful for the
     Landlord and all persons authorised by it to enter upon the Demised
     Premises and to carry out or procure to be carried out all or any of the
     works referred to in such notice and the cost of so doing and all expenses
     incurred thereby shall be paid by the Tenant to the Landlord on demand as a
     liquidated debt (together with interest thereon at the Prescribed Rate from
     the date of expenditure until the date of actual payment (both dates
     inclusive))

3.12 Dangerous Materials and Machinery: Except in properly designed stores or
     containers and in accordance with the recommendations and requirements of
     any competent authority and the Insurers and except with the prior written
     consent of the Landlord and

                                       13
<PAGE>

     the Insurers (such consent not to be unreasonably withheld in the case of
     the Landlord) not to bring into nor keep on the Demised Premises or any
     part thereof any article or thing which is or may become dangerous
     offensive radio-active or explosive or unusually combustible inflammable or
     which might increase the risk of fire or explosion or which might attack or
     in any way injure by percolation corrosion or otherwise the Demised
     Premises or the keeping or using whereof may contravene any statute or
     local regulation or bye-law AND not to keep or operate on the Demised
     Premises or any part thereof any engine or machinery of any kind other than
     machinery normally used in offices or in research and development
     departments which does not cause any undue vibration or undue noise and is
     unlikely to become a nuisance or disturbance to the Landlord or the owners
     tenants or occupiers of any adjoining or neighbouring premises and not to
     install or operate any equipment machinery or apparatus or do or omit to do
     any act or thing in the Demised Premises which may cause the efficiency of
     any heating ventilation air conditioning and cooling system installed in
     the building to be diminished or impaired in any way whatsoever or the
     balance thereof in any way interfered with and not to permit any water
     damage to any part of the building or adjoining premises by reason of the
     bursting or overflowing of any Conduits

3.13 Overloading Floors and Services and Damage to the Demised Premises: Not to
     do on the Demised Premises anything which may subject the Demised Premises
     to any weight or strain beyond that which such premises are designed to
     bear with due margin for safety and in particular not to overload the
     floors of or the electrical installation in or the other Conduits to the
     Demised Premises or to any adjoining or neighbouring property nor suspend
     any excessive weight from the ceilings walls or stanchions or the structure
     of the Demised Premises

3.14 Conduits: To keep all Conduits in and/or exclusively serving the Demised
     Premises (save for those in connection with the Irrigation System) clean
     and protected from frost and not to allow to pass into the Conduits serving
     the Demised Premises any noxious or deleterious effluent or other substance
     which may cause any obstruction or deposit in or injury to the Conduits and
     in the event of any such obstruction or injury forthwith to make good all
     such damage at its own cost to the reasonable satisfaction of the Landlord

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3.15 Disposal of Refuse:

     (a)  not to deposit any refuse or rubbish of any kind on any part of the
          Demised Premises save in a container or containers of the kind and in
          the location specified by the Landlord and if the Local Authority
          shall not provide a service or a sufficient service for the collection
          thereof to prepare all refuse and rubbish for collection in the manner
          and at times and places specified by the Landlord for the collection
          of refuse and to arrange for collection thereof at the Tenant's
          expense

     (b)  not to burn any refuse or rubbish of any kind in or about the Demised
          Premises

3.16 Exhibiting Articles: Not to place or exhibit or expose outside the Demised
     Premises any produce goods or things of any kind whatsoever

3.17 Obstruction of Common Areas: Not to do any act or thing whereby any area or
     item over which the Tenant may have rights of access or use including any
     road path passage building wall fence gate door structure plant equipment
     Conduits easement facility service or supply may be damaged or the normal
     use thereof by others may be obstructed or hindered in any way whatsoever
     nor park in an unauthorised location nor to permit the Tenant's Personnel
     to obstruct damage or impair the same

3.18 Obstruction of Windows: Not to cover or otherwise obscure the windows of
     the Demised Premises (other than blinds or other suitable window covering)
     or place any objects upon any of the ventilator units (if any) and not in
     any way to obstruct the said units

3.19 Prohibited Uses:

     (a)  not to use the Demised Premises or any part thereof for any illegal or
          immoral purposes or for any dangerous noisy noxious offensive or
          dangerous trade or business manufacture or occupation whatsoever or
          for any public religious or political meeting public exhibition or
          public show or spectacle or entertainment of any kind or for
          residential or sleeping purposes

     (b)  not to use the Demised Premises or any part thereof for gambling
          betting gaming or wagering or as a betting office nor for the sale of
          alcohol nor to play or use any

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<PAGE>

          recorded sound musical instrument record player loudspeaker amusement
          machine or similar apparatus thereon nor display any illuminated
          moving display or flashing lights nor to hold any auction thereon

     (c)  not to do any act deed or thing in or about or in connection with the
          Demised Premises which may be or become a nuisance or which may be or
          grow or lead to the damage or disturbance of the Landlord or the
          owners tenants or occupiers of any adjoining or neighbouring premises
          or which may constitute a breach of any of the provisions of any Act
          or Acts of Parliament for the time being in force whether affecting
          the Landlord or any of its present or future property (including the
          Demised Premises) or which may be in any way calculated to injure the
          character amenity or value of such property

     (d)  not to keep any animal fish reptile or bird on the Demised Premises

3.20 Authorised Use: Not to use the Demised Premises or any part thereof other
     than for a purpose appropriate to a science park that it is to say any one
     or more of the following uses:

     (a)  scientific research with associated offices and support facilities and
          buildings ancillary to such purposes

     (b)  scientific research associated with industrial production

     (c)  light industrial production of a kind which is dependent on regular
          consultation with either or both of the following:

          (i)  the Tenant's own research development and design staff
               established in the Cambridge Study Area

          (ii) the scientific staff or facilities of Cambridge University or of
               local scientific institutions

     (d)  ancillary buildings and works appropriate to the use of the Demised
          Premises as an integral part of a science park

     (e)  ancillary staff restaurant

                                       16
<PAGE>

     (f)  ancillary staff leisure facilities

     PROVIDED THAT if during the Term of this Lease the new use Clause as
     defined in the Superior Lease comes into operation with regard to the
     Superior Lease the new use Clause (as hereinbefore defined) shall be added
     to this Clause by way of addition to the use permitted hereunder and not in
     substitution for the use permitted hereunder PROVIDED FURTHER THAT if the
     Planning Agreements (as that expression is defined in the Superior Lease)
     shall cease to have effect in relation to phases 1  3  4 and 5 of the
     Superior Landlord's estate then the Landlord will endeavour to persuade the
     Superior Landlord to modify or vary the user clause in the Superior Lease
     (but not in such a way as may adversely affect the Tenant)

3.21 Alterations: Not at any time during the Term to make any alterations
     additions or improvements whatsoever in or to the Demised Premises or to
     any of the electrical installations or any part thereof whether internally
     or externally nor to cut maim or remove any of the walls beams columns or
     other structural parts of the Demised Premises or make any change in or to
     the existing design or appearance of the Demised Premises PROVIDED THAT the
     Tenant may with the prior written consent of the Landlord (such consent not
     to be unreasonably withheld or delayed) carry out internal non-structural
     alterations to the electrical installations and minor structural
     alterations which do not affect the structural integrity of the Demised
     Premises on condition that the said consent is contained in a formal
     licence setting out such reasonable conditions as the Landlord may
     stipulate including if the Landlord so requires the provision that the
     Demised Premises are to be reinstated at the Tenant's expense to the
     satisfaction of the Landlord at the end or sooner determination of the Term
     (howsoever determined) AND PROVIDED FURTHER THAT the Tenant may without the
     consent of the Landlord install move and remove any internal demountable
     partitioning and associated electrical works on condition that the Tenant
     shall supply full details of such works (including plans) within 28 days of
     the same having been carried out and that any such partitioning is removed
     and the Demised Premises reinstated at the Tenant's expense to the
     satisfaction of the Landlord at the end or sooner determination of the Term
     (howsoever determined)

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<PAGE>

3.22 Signs and Advertisements: Not at any time during the Term to affix paint or
     exhibit on the exterior of the Demised Premises (or in the interior thereof
     so that it can be seen from outside the Demised Premises) any aerial mast
     satellite dish television moving display showcase name flag placard sign
     poster signboard bill plate nameplate notice board or other advertisement
     whatsoever including notices stating the name and business of the Tenant
     save such as have been previously approved by the Landlord (such approval
     not to be unreasonably withheld or delayed) PROVIDED THAT notwithstanding
     the foregoing or any approval given as aforesaid if in the reasonable
     opinion of the Landlord any such sign or other matter as aforesaid which
     may be affixed painted or exhibited shall be or become offensive or
     unsightly the same shall be removed immediately upon request being made by
     the Landlord and the same shall be removed in any event by the Tenant upon
     determination of the Term the Tenant making good any damage caused

3.23 Encroachment and Easements:

     (a)  not to block up darken obstruct or obscure any external doorway
          passage window light grating or opening belonging to the Demised
          Premises nor make nor allow any new window light opening doorway
          passage drain or other encroachment or easement into against or upon
          or over the Demised Premises or any part thereof AND in case any
          encroachment or easement whatsoever shall be attempted to be made or
          acquired by any person whomsoever to give notice thereof in writing to
          the Landlord without delay upon the same coming to the notice of the
          Tenant and to permit the Landlord and all persons authorised by it to
          enter upon the Demised Premises to ascertain the nature and extent of
          any such encroachment or easement AND at the joint cost of the
          Landlord and the Tenant to adopt such means as the Landlord may
          require for preventing any such encroachment or the acquisition of any
          such easement

     (b)  not to give to any third party any acknowledgment that the Tenant
          enjoys the access of light to any of the windows or openings in the
          Demised Premises by the consent of such third party nor to pay to any
          such third party any sum of money nor enter into any agreement with
          such third party for the purpose of inducing or binding such third
          party to abstain from obstructing the access of light to any of

                                       18
<PAGE>

          such windows or openings and in the event of any of the owners or
          occupiers of any adjoining or neighbouring land or building doing or
          threatening to do anything which obstructs the access of light to any
          of the said windows or openings to notify the same forthwith to the
          Landlord

3.24 Alienation:

     (a)  not to assign (which shall include any equitable assignment) underlet
          charge grant any security interest over or part with or share
          possession or occupation of the whole or any part or parts of the
          Demised Premises nor to hold its interest in the Demised Premises or
          any part thereof as nominee or upon trust for any third party save in
          accordance with the provisions of this Clause 3.24

          PROVIDED ALWAYS THAT the Tenant may without the necessity of obtaining
          the consent of the Landlord share occupation of the whole or any part
          or parts of the Demised Premises with a company that is a member of
          the same group as the Tenant (as defined by Section 42 of the Landlord
          and Tenant Act 1954) subject to:

          (i)   the Tenant notifying the Landlord of the commencement or
                termination of each such arrangement;

          (ii)  any such sharing of occupation terminating forthwith upon any
                such company or companies ceasing to be a member or members of
                the same group as the Tenant; and

          (iii) no relationship of landlord and tenant being thereby created

          For the avoidance of doubt any such sharing of occupation shall not
          constitute an underletting within the meaning of Clause 3.24(c)

     (b)  in the case of an assignment of the whole of the Demised Premises
          prior to such assignment all the conditions set out below (being
          conditions specified for the purposes of Section 19(1A) of the
          Landlord and Tenant Act 1927 (as amended by Section 22 of the Landlord
          and Tenant (Covenants) Act 1995)) have been complied with in relation
          to that assignment which conditions are as follows:

                                       19
<PAGE>

          (i)   at the time of the assignment there are no arrears of Rents or
                other monies due to the Landlord and there is no subsisting and
                material breach of any of the covenants on the part of the
                Tenant herein contained; and

          (ii)  the Tenant has entered into an Authorised Guarantee Agreement as
                defined in the Landlord & Tenant (Covenants) Act 1995
                guaranteeing the proposed assignee's performance of the
                covenants on the part of the Tenant in such form as the Landlord
                may reasonably require; and

          (iii) the proposed assignee has provided references (and copies of the
                letters leading to the giving of such references) from its bank
                accountant and (if possible) solicitors and any current landlord
                in each case satisfactory to support payment by the assignee of
                sums equal to the current Rents or an increased sum in respect
                of an imminent rent review as estimated by the Landlord acting
                reasonably; and

          (iv)  where an assignment to the proposed assignee would not
                materially reduce the value of the Landlord's interest in the
                Demised Premises or materially and adversely affect the
                Landlord's ability to dispose of the reversion to all or any
                part of the Demised Premises; and

          AND in every case and in addition to the above conditions the Landlord
          has given its consent to the Tenant's assignment which must not be
          unreasonably withheld or delayed; and

     (c)  Underlettings: Not to underlet any part or parts of the Demised
          Premises except a Permitted Part or Permitted Parts but so that at no
          time shall there be more than three occupiers of the Demised Premises
          and further not to underlet the Demised Premises in whole or a
          Permitted Part or Permitted Parts unless sub-clause 3.24(c) and the
          following conditions have been fulfilled viz:

          (i)   any such underletting or underlettings of part shall lawfully
                exclude Sections 24 to 28 inclusive of the Landlord and Tenant
                Act 1954 (as amended by Section 5 of the Law of Property Act
                1969) and where the

                                       20
<PAGE>

                underletting comprises a part of a floor of the Demised Premises
                the Landlord (acting reasonably) shall have approved (such
                approval not to be unreasonably withheld or delayed) the
                configuration of the part of the Demised Premises to be the
                subject of the underletting

          (ii)  that prior to the grant of any underlease the undertenant shall
                have entered into a direct covenant with the Landlord (in such
                form as the Landlord may reasonably require) to observe and
                perform the covenants on the part of the Tenant herein contained
                (except the covenant to pay the Principal Rent hereby reserved)
                and the conditions herein contained insofar as the same are
                applicable to the premises to be underlet and the covenants on
                the part of the undertenant contained in the underlease
                throughout the term of the underlease

          (iii) any underlease shall contain an absolute prohibition on the
                undertenant further underletting (though not assigning) the
                premises thereby demised as a whole or any part or parts thereof
                and shall contain provisions enabling the underlease to be
                determined by the Tenant

          (iv)  that every underletting of the Demised Premises shall be at a
                rent which shall have been approved by the Landlord prior to
                such underletting such approval not to be unreasonably withheld
                or delayed to a rent which shall be not less than the full rack
                rental value of the Demised Premises at the date of the
                underletting or an apportioned part thereof in respect of
                underlettings of less than the whole of the Demised Premises
                (having regard where appropriate to the requirement that
                Sections 24 to 28 (inclusive) of the Landlord and Tenant Act
                1954 (as amended by Section 5 of the Law of Property Act 1969)
                are to be excluded) without a premium and payable in advance on
                the usual quarter days and only one quarter in advance and on a
                full repairing basis and shall contain covenants on the part of
                the undertenant corresponding with those contained in this Lease
                insofar as the same are applicable to the premises to be
                underlet and reasonable and appropriate given the terms of the

                                       21
<PAGE>

                Underlease and shall contain conditions mutatis mutandis on
                similar terms to those of this sub-clause PROVIDED THAT in this
                Clause 3.24(c)(iv) the expression "full rack rental value" shall
                mean the open market rental value for similar quality space
                being leased on terms (excluding inter alia the term of years)
                similar to those contained in this Lease (but with regard to the
                fact that the Lease is excluded from the Landlord & Tenant Act
                1954 (Sections 24 to 28 inclusive) but taking account of the
                term of years to be granted by the Underlease

     (d)  Consent of the Landlord: Without prejudice to or in any way derogating
          from the foregoing covenants contained in this sub-clause no
          assignment charge or underletting of the whole or underletting of any
          parts of the Demised Premises whether by the Tenant or any person
          claiming title from the Tenant (including any undertenant) shall be
          made without the previous consent in writing of the Landlord (such
          consent not to be unreasonably withheld or delayed)

     (e)  Surrender and Variations of Underleases and Enforcement of Underlease
          Covenants:

          (i)   not to accept the surrender of or vary or waive any material
                term of any underlease granted by the Tenant without the
                previous written consent of the Landlord (such consent not to be
                unreasonably withheld or delayed)

          (ii)  not to reduce waive commute set off or otherwise vary whether
                directly or indirectly the rents reserved by any underlease

          (iii) in the event of a breach non-performance or non-observance of
                any of the covenants conditions agreements and provisions
                contained or referred to in this Lease by any undertenant or
                other person holding the Demised Premises or any part thereof as
                undertenant of the Tenant forthwith upon discovering the same to
                take and institute at its own expense all necessary steps and
                proceedings to remedy such breach non-performance or non-
                observance

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<PAGE>

3.25  Registration of Disposition: Within twenty-one days of every assignment
      assent transfer underlease or assignment of underlease or mortgage or
      charge or any other dealing with or any disposition whether mediate or
      immediate of or relating to the Demised Premises to give notice thereof in
      writing with particulars thereof to the solicitors for the time being of
      the Landlord and to produce to such solicitors for registration by them a
      certified copy of such assignment assent transfer underlease mortgage or
      charge or in the case of devolution of the interest of the Tenant not
      perfected by an assent within twelve months of the happening thereof to
      produce to the said solicitors a certified copy of the probate of the will
      or the letters of administration under which such devolution arises and to
      pay to the Landlord's solicitors a reasonable registration fee (being not
      less than forty five pounds) together with the registration fee payable to
      any superior landlord or its solicitors in respect of each such instrument

3.26  Disclosing Information about the Demised Premises
      (a)  To give details to the Landlord in writing of any change of name
           address or registered office of the Tenant or any surety within three
           weeks after such change

      (b)  Upon making any application or request in connection with the Demised
           Premises or the provisions of this Lease to give to the Landlord such
           information as the Landlord may properly require and from time to
           time on reasonable demand during the Term to furnish the Landlord
           with full particulars of all derivative interests of or in the
           Demised Premises including details of the actual user particulars of
           the rents rent reviews and service and maintenance charges payable in
           respect of such derivative interests

3.27  Landlord's Costs: To pay to the Landlord within seven working days of a
      written demand all fair and proper costs charges and expenses (including
      but without prejudice to the generality of the foregoing legal costs
      architects' and surveyors' fees the Landlord's internal management fee and
      other professional costs and fees) properly incurred by the Landlord:

      (a)  incidental to or in contemplation of the preparation and service of a
           notice under Section 146 of the Law of Property Act 1925 or in
           contemplation of any

                                       23
<PAGE>

           proceedings under Sections 146 or 147 of the said Act (whether or not
           any right of re-entry or forfeiture has been waived by the Landlord
           or a notice served under the said Section 146 is complied with by the
           Tenant or the Tenant has been relieved under the provisions of the
           said Act and notwithstanding forfeiture is avoided otherwise than by
           relief granted by the Court) and to indemnify and keep indemnified
           the Landlord against all costs charges expenses claims and demands
           whatsoever in respect of the said proceedings and the preparation and
           service of the said notice

      (b)  incidental to or in contemplation of the preparation and service of a
           schedule of dilapidations at any time during or within six months
           after the expiration of the Term but relating only to dilapidations
           which arise during the Term together with the costs of any necessary
           supervision of any reinstatement of the Demised Premises

      (c)  in connection with or in procuring the remedying of any breach of
           covenant on the part of the Tenant contained in this Lease

      (d)  in connection with any application for any consent required under
           this Lease (such costs to include management fees and expenses)
           whether or not such application is withdrawn by the Tenant or consent
           be granted or refused

3.28  Statutory Requirements: At all times during the Term at the Tenant's own
      expense to do and execute or cause to be done and executed all such works
      acts and things and to provide and maintain all arrangements required by
      and to observe and comply in all respects with the provisions and
      requirements of any and every enactment including (without prejudice to
      the generality of such expression) the provisions of the Offices Shops and
      Railway Premises Act 1963 the Fire Precautions Act 1971 the Defective
      Premises Act 1972 and the Health and Safety at Work etc Act 1974 or
      required by any government department public local or other authority or
      duly authorised officer or Court of competent jurisdiction acting under or
      in pursuance of any enactment as are or shall be directed or required to
      be executed or provided or maintained at any time during the Term upon or
      in respect of the Demised Premises or the user thereof for any purposes or
      the employment therein of any person or any fixtures machinery plant or
      chattels for the

                                       24
<PAGE>

      time being fixed thereto or being thereupon or used for the purposes
      thereof whether by the owner or occupier thereof and to indemnify and keep
      indemnified the Landlord at all times from and against all actions
      proceedings costs charges losses expenses claims and demands arising out
      of any failure by the Tenant to observe and perform any of its obligations
      under this sub-clause AND not at any time during the Term to do or omit on
      or about the Demised Premises any act or thing by reason of which the
      Landlord may under any enactment incur or have imposed upon it or become
      liable to pay any penalty damages compensation costs charges or expenses

3.29  Planning: In relation to the Planning Acts:

      (a)  at all times during the Term to comply in all respects with all
           requirements of or having validity under the Planning Acts and with
           the conditions of any planning permission relating to the Demised
           Premises and not to do or omit anything on or in connection with the
           Demised Premises which shall be in contravention of the Planning Acts
           or of any licence consents permissions approvals and condition (if
           any) granted or imposed thereunder or under any enactment repealed
           thereby and to indemnify the Landlord against all proceedings damages
           penalties costs charges claims and demands in respect of such acts
           and omissions or any of them and against the costs of any application
           for planning permission made by the Tenant and the works done in
           pursuance thereof

      (b)  during the Term so often as occasion shall require at the expense in
           all respects of the Tenant to obtain all licences consents and
           permissions as may be required for the carrying out by the Tenant of
           any operations on the Demised Premises or the commencement
           continuance or renewal by the Tenant thereon of any use thereof which
           may constitute development within the meaning of the Planning Acts
           but so that the Tenant shall not make any application for planning
           permission or give any notice to any authority of the commencement or
           carrying out of any development (or give any notice of an intention
           to commence or carry out the same) without the previous consent in
           writing of the Landlord (such consent not to be unreasonably withheld
           or delayed if such application would not be in breach of any other
           provisions herein contained)

                                       25
<PAGE>

      (c)  without prejudice to any other provision of this Lease not to carry
           out or make any alteration or addition to the Demised Premises or
           change any use thereof (being an alteration or addition or change of
           use for which a planning permission needs to be obtained) before a
           planning permission therefor has been produced to the Landlord and
           acknowledged by it in writing as satisfactory to it (such
           acknowledgement not to be unreasonably withheld or delayed)

      (d)  unless the Landlord shall otherwise direct to carry out before the
           expiration or sooner determination of the Term (disregarding any
           statutory continuation thereof) any works required to be carried out
           to the Demised Premises by a date subsequent thereto by reason of any
           limitation or condition imposed by a planning permission consent or
           approval implemented or partially implemented by the Tenant or by a
           person deriving title through or under or acting on behalf of the
           Tenant or if the work cannot lawfully be done before the end of the
           Term as aforesaid to pay to the Landlord the proper estimated cost of
           carrying it out together with a sum equivalent to the rents which
           would have been payable hereunder if the Term had continued until the
           date that the Landlord expects to complete such work

      (e)  if and when called upon so to do to produce to the Landlord all such
           plans documents and other evidence as it may properly require in
           order to satisfy itself that the provisions of this covenant have
           been complied with

      (f)  to pay within seven days of a written demand the whole amount of any
           levy charge tax or imposition assessed or imposed in respect of any
           development of the Demised Premises carried out after the date of
           this Lease by the Tenant or any permission consent or approval for
           such development PROVIDED THAT if any such levy charge tax or
           imposition is assessed or imposed upon the Landlord or the interest
           of the Landlord in the Demised Premises then the Tenant shall
           indemnify and keep indemnified the Landlord in respect thereof
           including any interest payable thereon and any appeal against any
           such assessment or imposition shall be conducted entirely at the
           expense of the Tenant

                                       26
<PAGE>

      (g)  not without the consent in writing of the Landlord (such consent not
           to be unreasonably withheld or delayed) to take any step which would
           involve any person or interest in liability to any levy charge or
           imposition as mentioned in this Clause 3.29

3.30  Statutory Notices: Forthwith upon the receipt of the same to give to the
      Landlord a certified copy or where no copy is available full particulars
      in writing of any notice permission order or proposal for a notice
      permission or order concerning the Demised Premises or the use or
      condition thereof or otherwise concerning the Tenant or occupier by any
      Government Department local or public authority under or by virtue of any
      statutory powers and if so required by the Landlord to produce the
      original of such notice permission or order or proposal as aforesaid to
      the Landlord AND ALSO without delay to take all necessary steps to comply
      with any such notice or order AND ALSO at the request of the Landlord but
      at the joint cost of the Landlord and the Tenant to make or join with the
      Landlord in making such objections or representations against or in
      respect of any such notice permission order or proposal as aforesaid as
      the Landlord shall deem expedient

3.31  Fire Precautions and Equipment:

      (a)  at all times during the Term to comply with all requirements and
           recommendations from time to time of the appropriate authority and
           the insurers in relation to fire precautions

      (b)  to keep the Demised Premises sufficiently supplied and equipped with
           such fire prevention fire detecting fire fighting fire alarm and
           extinguishing equipment as shall from time to time be required by law
           or by the insurers or by the fire or other competent authority and
           such equipment shall be open to inspection and shall be maintained to
           the reasonable satisfaction of the Landlord AND not to obstruct or
           permit or suffer to be obstructed the access to or means of working
           such equipment or the means of escape from the Demised Premises in
           case of fire

      (c)  to remove from all parts of the Demised Premises all waste and
           inflammable material of a like nature without delay

                                       27
<PAGE>

3.32  Reletting and Sale Notices: to permit the Landlord and all persons
      authorised by it upon prior notice at all reasonable times during the Term
      to enter upon the Demised Premises and to affix and retain without
      interference upon any suitable part of the Demised Premises (but not so as
      to unnecessarily obstruct the access of light and air to the Demised
      Premises) a notice for the reletting or the sale of the same and not to
      remove or obscure the said notice and to permit all persons authorised in
      writing by the Landlord or its agents to view the Demised Premises at all
      reasonable hours upon reasonable notice being given

3.33  Informing the Landlord of Defects and Display of Notices: Immediately the
      same shall come to the notice of the Tenant to inform the Landlord of any
      defect in the Demised Premises (including any relevant defect within the
      meaning of Section 4 of the Defective Premises Act 1972) which might give
      rise to a duty imposed by common law or statute on the Landlord in favour
      of the Tenant or any other person and of any damage to or destruction of
      the Demised Premises or any part thereof howsoever caused and at all times
      during the Term to display and maintain all notices (including the wording
      thereof) which the Landlord may from time to time reasonably require to be
      displayed at the Demised Premises

3.34  Indemnifying Landlord:
      (a)  all sums payable hereunder by the Tenant shall be paid to the
           Landlord on demand or on the due dates for payment specified in
           Clause 2 hereof in full without any deduction withholding
           counterclaim or set off and if the Tenant is compelled by law to make
           any deduction or withholding from any such sums or if any payment
           hereunder shall be or become subject to any tax duty levy or impost
           of any nature (whether before or after the same has been paid to the
           Landlord) the Tenant shall immediately pay to the Landlord such
           additional amount or amounts as will result in payment to and
           retention by the Landlord of the full amount or amounts which would
           have been received and retained by the Landlord but for such
           deduction or withholding or the imposition of such tax duty levy or
           impost

                                       28
<PAGE>

      (b)  to be responsible for and to indemnify the Landlord against all
           damage occasioned to the Demised Premises or any adjacent or
           neighbouring premises or to any person caused by any act default or
           negligence of the Tenant or the Tenant's personnel

3.35  Landlord's Regulations: to comply with such proper regulations or
      directions as may from time to time be made by the Landlord and notified
      to the Tenant for the proper management of the Demised Premises or
      premises other than the Demised Premises (if any) over which the Tenant
      has rights under this Lease PROVIDED THAT they do not conflict with the
      provisions herein contained the Landlord shall have power to waive revoke
      amend or add to any such regulations and shall notify the Tenant of such
      revocation amendments or additions

3.36  Providing Details of Keyholders to the Demised Premises: on request to
      provide the Landlord with the names addresses and telephone numbers of the
      holders of keys to the Demised Premises

3.37  Value Added Tax:

      (a)  to pay to the Landlord any Value Added Tax at the rate for the time
           being in force properly payable in respect of any rent or other
           payments due from the Tenant in connection with this Lease and all
           sums stated in this Lease to be payable by the Tenant shall be
           exclusive of any Value Added Tax properly payable thereon and the
           Landlord shall provide a Value Added Tax invoice therefor

      (b)  in every case where the Tenant is obliged to reimburse the Landlord
           in respect of any payment made by the Landlord in connection with
           this Lease the Tenant shall also reimburse to the Landlord any Value
           Added Tax paid by the Landlord on any such payment (where not
           recovered by the Landlord) and the Landlord shall (where appropriate)
           provide the Tenant with a Value Added Tax invoice therefor

3.38  Insurance: the Tenant shall (unless the Landlord informs the Tenant in
      writing that the Landlord intends to effect such insurance) insure against
      any claims for death injury or third party property damage arising on or
      in respect of the Demised Premises in such

                                       29
<PAGE>

      insurance office and upon such terms and for such amount as the Landlord
      shall from time to time approve (such approval not to be unreasonably
      withheld or delayed); and

      PROVIDING THAT:

      (a)  the Tenant shall produce to the Landlord whenever so reasonably
           required a copy of the policy of such insurance and the receipt for
           the current year's premium

      (b)  if the Tenant shall default in keeping or effecting such insurance or
           in producing any policy or receipt or suitable evidence from the
           insurers that the policy is on foot the Landlord may effect such
           insurance and reclaim the cost thereof from the Tenant

3.39  Observance of Covenants and Conditions referred to in the Fifth Schedule:
      (a)  to observe and perform any covenants conditions stipulations
           exceptions reservations easements and other matters referred to or
           contained in the documents referred to in the Fifth Schedule (other
           than the Superior Lease referred to therein) so far as they relate to
           the Demised Premises and are capable of being enforced and to
           indemnify and keep indemnified the Landlord against any liability
           whatsoever arising out of the breach non-observance or non-
           performance thereof by the Tenant

      (b)  to observe and perform the covenants and obligations on the part of
           the Landlord as lessee under the Superior Lease as far as the same
           affect and relate to the Demised Premises and so far as the same do
           not relate to the payment of rent and insurance the carrying out of
           the New Lessees Works (as defined in the Superior Lease) and are not
           inconsistent with the terms of this Lease

4.  LANDLORD'S COVENANTS

    The Landlord HEREBY COVENANTS with the Tenant as follows:

                                       30
<PAGE>

4.1   Quiet Enjoyment: as long as the Tenant pays the Rents and performs and
      observes the covenants and agreements on the part of the Tenant
      hereinbefore contained:

      (a)  the Tenant shall peaceably hold and enjoy the Demised Premises during
           the Term without any interruption by the Landlord or any person
           lawfully claiming through under or in trust for it or by title
           paramount

      (b)  the Landlord will indemnify the Tenant against any action taken or
           claims made by any superior lessor of the Demised Premises due to the
           breach of any obligations on the part of the Landlord to perform the
           lessee's covenants contained in any superior lease (so far as the
           Tenant is not liable for such performance under the Tenant's
           covenants herein contained) and to keep the Tenant indemnified
           against all actions proceedings costs claims and demands in any way
           relating thereto and not to omit or suffer anything to be done
           whereby the Superior Lease may be avoided or forfeited

4.2   (a)  To provide services: unless prevented by circumstances beyond its
           control and so that the Landlord shall be entitled on giving
           reasonable notice to the Tenant (and in the case of electrical
           installations or any works which may affect the power supply the
           notice period shall not be less than two working days (save in case
           of emergency)) to interrupt temporarily the Services referred to in
           Clause 3.4 hereof for such length of time as shall be necessary to
           enable inspections maintenance repairs and replacements to be carried
           out such time or times to be notified (except in the case of
           emergency) in advance to the Tenant the Landlord will use all
           reasonable endeavours to furnish or procure those services and carry
           out or procure the functions referred to in the Fourth Schedule

      (b) To pay the proportion of the Service Charge in respect of the other
           premises comprised in the Superior Lease and the Lease dated 27 March
           1990 and registered under Title Number CB 121575 whilst the Landlord
           is the registered proprietor of that Title Number which is not paid
           by any occupational tenant as a result of there being no occupational
           lease of such property

                                       31
<PAGE>

      (c)  To maintain and repair in good and substantial condition the
           Irrigation System (and to make good forthwith to the reasonable
           satisfaction of the Tenant any damage caused to the demised premises
           by virtue of leading or bursting of the Irrigation System in the
           event that this should no longer be an Insured Risks)

4.3   Superior Lease: to pay the rent reserved by the Superior Lease and to
      perform so far as the Tenant is not liable for such performance under the
      covenants on its part contained in this Lease the lessee's covenants and
      conditions contained in the Superior Lease and to indemnify and keep
      indemnified the Tenant against all actions claims proceedings costs
      expenses and demands in any way relating thereto; and

5.    INSURANCE

      The Landlord and the Tenant hereby mutually covenant with each other and
      agree as follows:

5.1   Landlord to Insure: that the Landlord will at all times during the Term
      (unless such insurance shall have been avoided or vitiated by virtue
      (wholly or in part) of any act neglect default or omission of the Tenant
      or any sub-tenant or their respective personnel) insure and keep insured
      the Demised Premises (excluding the Tenant's fixtures and fittings and
      Tenant's stock) for a sum which is not less than the Full Reinstatement
      Cost with the Insurers against the Insured Risks and against the Loss of
      Rent and that the Landlord will if required produce to the Tenant a copy
      of the policy and a copy of the receipt for the current premium and in
      case of destruction or damage by any of the Insured Risks (unless the
      insurance moneys become or shall have become irrecoverable by virtue
      (wholly or in part) of any act or default of the Tenant the Landlord will
      with all reasonable speed and subject to all necessary consents being
      obtained cause all moneys received in respect of such insurance (other
      than in respect of the Loss of Rent and fees) to be forthwith laid out in
      or incidental to Reinstatement of the Demised Premises and the access
      thereto (excluding the Tenant's fixtures and fittings and the Tenant's
      stock) PROVIDED THAT if the option for determination contained in Clause
      5.7 shall be exercised or the rebuilding or reinstatement of the Demised
      Premises shall be prevented

                                       32
<PAGE>

      or frustrated the Landlord shall be relieved from the obligation
      hereinbefore contained to cause to be laid out the said net proceeds of
      such insurance as aforesaid and the proceeds of such insurance shall
      belong to the Landlord

5.2   Insurance Money being irrecoverable: that if any insurance money under any
      insurance policy effected by the Landlord shall be wholly or partly
      irrecoverable by reason solely or in part of any act or default of the
      Tenant or the Tenant's Personnel then and in every such case the Tenant
      will forthwith pay to the Landlord the whole of the insurance moneys which
      are so irrecoverable by reason of the Tenant's (or the Tenant's Personnel)
      act or default

5.3   Cesser of Rent: that if the Demised Premises or any part thereof or any
      essential access thereto shall be destroyed or so damaged by any of the
      Insured Risks as to render the Demised Premises unfit for occupation or
      use or inaccessible and provided that the policy or policies of insurance
      for the time being in force shall not have been vitiated or payment of the
      policy moneys withheld or refused in whole or in part in consequence of
      any act neglect or default of the Tenant or the Tenant's Personnel then
      the Principal Rent and the Service Charge or a fair proportion thereof
      according to the nature and extent of the damage sustained shall be
      suspended until the earlier of (i) the date when the Demised Premises or
      the destroyed or damaged portion thereof or essential access thereto shall
      be again rendered fit for occupation or use (or rendered accessible as the
      case may be) and (ii) the date of expiry of the Loss of Rent period and
      any dispute as to the proportion or ascertainment of rent to be suspended
      or the period of suspension shall be referred to the decision of a single
      arbitrator to be appointed (in the absence of agreement between the
      parties) upon the written application of either party by the President or
      Secretary for the time being of the Royal Institution of Chartered
      Surveyors (or by the Court if such an appointment has not been made within
      two months of application) pursuant to the provisions of the Arbitration
      Act 1996

5.4   Insurance becoming Void: that the Tenant will not do or omit to do any act
      matter or thing whatsoever the doing or omission of which would or might
      make void voidable or vitiate any policy or policies of insurance for the
      time being in force in respect of or including or covering the Demised
      Premises or any adjoining or neighbouring premises

                                       33
<PAGE>

      or whereby the rate of premium thereon may be increased or the renewal
      thereof may be refused and forthwith will repay on demand to the Landlord
      all sums paid by way of increased premiums and all expenses incurred by
      the Landlord in or about the renewal of such policy or policies rendered
      necessary by a breach of this covenant

5.5   Requirements of Insurance:  that the Tenant will at all times comply with
      all the requirements and recommendations of the Insurers

5.6   Notice by Tenant: that forthwith upon the happening of any event or thing
      against which insurance shall have been effected by the Landlord the
      Tenant will give notice thereof to the Landlord

5.7   Determination following Destruction: that if any destruction or damage
      shall render the Demised Premises wholly or substantially unfit for
      occupation and the same shall not have been rebuilt and/or reinstated as
      aforesaid within three years from the date the said destruction or damage
      occurs then either the Landlord or the Tenant may at any time thereafter
      determine this Lease by giving to the other not less than one months'
      notice in writing to that effect whereupon this Lease and everything in it
      shall cease and be determined but such determination shall be without
      prejudice to any claim by either party against the other in respect of any
      antecedent breach of covenant

5.8   Tenant not to Insure: that subject to the provisions of Clause 3.38 above
      the Tenant will not effect any insurance against any of the Insured Risks
      in respect of or relating to the Demised Premises except that the Tenant
      may if it wishes insure against explosion of boilers not being domestic
      boilers if these are not covered by the Landlord's Insurance as a matter
      of fact

6.    RENT REVIEWS

6.1   In this Clause the following words and expressions shall have the
      following meanings:

      "Market Rental Value": means the yearly rack rent which would reasonably
      be expected to become payable in respect of the Demised Premises after the
      expiry of a rent

                                       34
<PAGE>

      free period for fitting out purposes and/or after the giving of such
      inducements in lieu thereof as would (in either such case) be negotiated
      in the open market between a willing lessor and a willing lessee upon a
      letting of the same as a whole by a willing landlord to a willing tenant
      in the open market at the relevant Review Date for a term of ten years
      commencing on the relevant Review Date with vacant possession without fine
      or premium or other capital sum and on the following further assumptions:

      (a)  the Demised Premises are to be let subject to the provisions of this
           Lease (other than the amount of Principal Rent but including these
           provisions for rent review)

      (b)  all parts of the Demised Premises are fit and available for immediate
           occupation and are ready to suit the requirements of the tenant

      (c)  the covenants and provisions contained in this Lease have been fully
           performed and observed (but without prejudice to any rights of any
           party in regard thereto)

      (d)  no work has been carried out on or about the Demised Premises which
           has diminished the rental value thereof

      (e)  in case the Demised Premises or any part thereof shall have been
           destroyed or damaged by any of the Insured Risks so as to render the
           Demised Premises unfit for occupation and use or unaccessible they
           have been rendered fit for occupation and use (or accessible (as the
           case may be))

      (f)  any rent free period for fitting out purposes has expired (or that an
           inducement in lieu thereof has been paid)

      (g)  the benefit of any planning or other consent current at the relevant
           Review Date is available also for such willing tenant

      (h)  the Demised Premises may be lawfully used for the use permitted by
           the Lease and taking no account of any effect on rent of:

      (i)  the fact that the Tenant or its predecessors in title or subtenant
           have been in occupation of the Demised Premises

                                       35
<PAGE>

      (ii)  any goodwill attached to the Demised Premises by reason of the
            carrying on the Demised Premises of any business by the Tenant or
            its predecessors in title and/or subtenants

      (iii) the existence at the relevant Review Date of any improvement to the
            Demised Premises carried out during the Term by the Tenant and/or
            any subtenants or prior thereto pursuant to any agreement for lease
            by the Tenant or its predecessors in title with the Landlord's prior
            consent (if required) other than an improvement effected at the
            Landlord's expense or pursuant to an obligation to the Landlord or
            its predecessors in title whether under this Lease or otherwise

      (iv)  any premium paid by the Landlord to the Tenant as an inducement to
            the Tenant to enter into this Lease

      (v)   any premium paid by the Tenant to the Landlord as a condition of the
            Tenant entering into this Lease

      (vi)  (so far as may be permitted by law) all statutory restrictions
            relating to the assessment and recovery of rent

      (vii) the Landlord's or the Tenant's estimate of the increased Principal
            Rent for any purpose

      "the President": the President (or if he is unable so to act then the Vice
      President or other duly authorised officer) for the time being of the
      Royal Institution of Chartered Surveyors

      "Review Dates": 25 March 2006 25 March 2011 and 25 March 2016 and such
      other date specified by the Landlord in accordance with Clause 6.5 and the
      expression the "relevant Review Date" shall be construed accordingly

                                       36
<PAGE>

6.2   The Principal Rent shall be reviewed on each Review Date and shall from
      the relevant Review Date be whichever is the higher of:

      (a)  the Market Rental Value as at that Review Date;

      (b)  the Principal Rent immediately before that Review Date; and

6.3   The Landlord and the Tenant shall endeavour to agree the Market Rental
      Value as at the relevant Review Date but if they fail to agree in writing
      by the date which is three months immediately before that relevant Review
      Date the Market Rental Value may be determined by a valuer to be appointed
      on the request of either the Landlord or the Tenant by the President
      PROVIDED ALWAYS THAT:

      (a)  the valuer shall be a Chartered Surveyor who shall have not less than
           ten years experience in valuing property similar to the Demised
           Premises in and shall be a partner or director of a reputable firm or
           company of Chartered Surveyors

      (b)  the valuer shall act as an arbitrator (unless the parties agree prior
           to the date of appointment that the valuer shall act as an expert)

      (c)  in the case of the valuer acting as arbitrator

           (i)  the arbitration shall be conducted in accordance with the
                Arbitration Act

           (ii) if any person appointed as the valuer shall die or become
                unwilling or incapable of acting or if for any other reason he
                is unable to act then the Landlord or the Tenant may request the
                President to appoint another valuer to act as an arbitrator in
                his place

                                       37
<PAGE>

      (d)  in the case of the valuer acting as expert

           (i)   the costs of the valuer shall be in his determination and
                 failing such determination such costs shall be borne by the
                 parties in equal shares

           (ii)  the valuer shall afford to the Landlord and the Tenant or their
                 representatives reasonable opportunity to make representations
                 (which he will exchange between the parties) and cross
                 representations to him; and

           (iii) if the person appointed as the valuer shall die or become
                 unwilling or incapable of acting or if for any other reason he
                 is unable to act then the Landlord or the Tenant may request
                 the President to appoint another valuer in his place to act as
                 an expert which procedure may be repeated as many times as
                 necessary

6.4  Such increased Principal Rent (if any) shall be payable on and from the
     relevant Review Date for the residue of the Term or until a greater rent is
     substituted therefor under this Clause but in the event of the Market
     Rental Value not having been agreed or determined at the relevant Review
     Date then the Principal Rent payable immediately prior to that Review Date
     shall continue to be payable until such agreement or determination and
     within fourteen days after such agreement or determination the Tenant shall
     pay the balance due (being the difference between the Principal Rent
     actually paid from that Review Date and the increased Principal Rent as
     agreed or determined payable from that Review Date up to and including the
     day preceding the next ensuing Quarter Day) together with interest at four
     per centum below the Prescribed Rate on such balance payable from the
     relevant Review Date until actual payment

6.5  If at any Review Date the Landlord must comply with any Enactment which
     restricts or modifies the Landlord's right herein to revise the Principal
     Rent or which shall restrict the Landlord's right to demand or accept
     payment of the full amount of the Principal Rent for the time being payable
     under this Lease then on each time that any such Enactment is removed
     relaxed or modified the Landlord may on giving at least one month's notice

                                       38
<PAGE>

     to the Tenant expiring after the date of each such removal relaxation or
     modification review the Principal Rent on the date of such notice expiring
     and the Principal Rent from such date to the next succeeding Review Date
     shall be determined in accordance with this Clause

6.6  Any variation of the Principal Rent pursuant to this Clause shall when
     agreed or determined be recorded by a memorandum endorsed upon or annexed
     to this Lease and counterpart hereof signed on behalf of the Landlord and
     the Tenant

6.7  Any delay in the seeking an appointment of a valuer shall in no way
     prejudice the right to review the Principal Rent and time shall not be of
     the essence in respect of any dates or periods mentioned in this Clause

7.   PROVISOS
     PROVIDED ALWAYS AND IT IS HEREBY AGREED AND DECLARED as follows:

7.1  Forfeiture: if the rents hereby reserved or any part thereof shall be
     unpaid for twenty one days after becoming payable (whether formally
     demanded or not) or if any of the covenants on the part of the Tenant
     herein contained shall not be materially performed or observed or if the
     Tenant (or if the Tenant is more than one person any of them) shall be
     adjudged a bankrupt or (being a company) shall go into liquidation (other
     than a voluntary liquidation for the purposes of amalgamation or
     reconstruction of a solvent company in respect of which the Landlord's
     consent has first been obtained such consent not to be unreasonably
     withheld or delayed) or if a Receiver Administrator Administrative Receiver
     or other encumbrancer takes possession of or shall be appointed in respect
     of the whole or any part of the Tenant's assets or if the Tenant shall make
     any arrangement with creditors for the liquidation of the debts of the
     Tenant by composition or otherwise or any voluntary arrangement as defined
     in the Insolvency Act 1986 or ceases to carry on its business as a whole or
     becomes unable to pay its debts within the meaning of Section 123 of the
     Insolvency Act 1986 then and in any of the said cases it shall be lawful
     for the Landlord or any person duly authorised by the Landlord in that

                                       39
<PAGE>

      behalf at any time thereafter to re-enter the Demised Premises or any part
      thereof in the name of the whole and thereupon this demise shall
      absolutely cease and determine but without prejudice to any right of
      action or remedy of any party hereto in respect of any antecedent breach
      of any of the covenants by any party hereto

7.2   Distress: if any part of the Rents sums or other payments hereby reserved
      or any part thereof shall be in arrears for twenty one days (whether
      legally demanded or not) it shall be lawful for the Landlord to enter upon
      the Demised Premises or any part thereof and to distrain and to dispose of
      in due course of law the distress or distresses then and there found and
      to apply the proceeds thereof in or towards payments so in arrear and all
      interest reserved as rent

7.3   No implied easements: nothing herein contained shall by implication of law
      or otherwise operate to confer upon the Tenant any easement right or
      privilege whatsoever over or against any adjoining or neighbouring
      property which would or might restrict or prejudicially affect the future
      rebuilding alteration development or user of such adjoining or
      neighbouring property and the Landlord shall have the right at any time to
      make such alterations to or to pull down and rebuild or redevelop any such
      adjoining or neighbouring property as it may deem fit without obtaining
      any consent from or making any compensation to the Tenant

7.4   No restrictions on adjoining property: nothing herein contained or implied
      shall impose or be deemed to impose any restriction on the use or
      development of any land or buildings not comprised in this Lease or give
      the Tenant the benefit of or the right to enforce or to have enforced or
      to prevent the release or modification of any covenant agreement or
      condition entered into by any purchaser from or by any tenant or occupier
      of the Landlord in respect of property not comprised in this Lease or
      shall operate to prevent or restrict in any way the use or development of
      any land not comprised in this Lease whether the same shall be subject to
      or free from covenants agreements declarations and stipulations similar to
      those herein contained and the Landlord shall have no obligation to ensure
      that any person granted or exercising any right shall exercise such rights
      in a manner permitting the Tenant to exercise any rights without
      interference

                                       40
<PAGE>

7.5  Exclusion of Landlord's liability:

     (a)  the Landlord shall not in any event be liable to the Tenant in respect
          of any failure of the Landlord to perform any of its obligations to
          the Tenant hereunder whether expressed or implied (except for the
          Landlord's covenant to insure) unless and until the Tenant has
          notified the Landlord of the facts giving rise to the failure and the
          Landlord has failed within a reasonable length of time to remedy the
          same and then in such case the Landlord shall be liable to compensate
          the Tenant only for loss or damage sustained by the Tenant after such
          reasonable time shall have elapsed

     (b)  no liability shall attach in respect of any breach of any positive
          covenant (other than covenants for the payment of money) on the part
          of the Landlord herein contained or implied so long as the Landlord
          shall be prevented from performing the same by statutory restrictions
          non-availability of labour or materials or matters beyond its control
          except that if such breach shall occur as aforesaid the Landlord shall
          immediately conditions permit remedy such breach

     (c)  the Landlord shall not in any circumstances incur any liability in
          respect of damage to person or property or otherwise by reason of any
          accidental damage which may be done to the Demised Premises or to any
          of the goods persons or property of the Tenant or any other person
          other than may be caused by the act neglect default or misfeasance of
          the Landlord its servants employees or agents and any services
          rendered to or for the Tenant on the Tenant's request by a servant or
          agent of the Landlord shall be deemed to have been rendered by that
          person as servant of the Tenant

7.6  No warranty as to permitted use: nothing in this Lease contained shall
     imply or warrant or be deemed to imply or warrant that the Demised Premises
     may under the provisions of the Planning Acts be used for the purpose
     herein authorised and the Tenant hereby acknowledges and admits that the
     Landlord has not given or made at any time any representation or warranty
     that any such use is or will be or will remain a permitted use under the
     Planning Acts and that notwithstanding that any such use as aforesaid might
     not be a permitted use within such provisions as aforesaid the Tenant shall
     remain fully

                                       41
<PAGE>

     bound and liable to the Landlord in respect of the obligations undertaken
     by the Tenant by virtue of this Lease without any compensation recompense
     or relief of any kind whatsoever

7.7  Notices:

     (a)  any notice to be given under this Lease shall be in writing and may be
          delivered to the relevant party or sent by registered first class
          prepaid letter or facsimile to the registered office of that party or
          to such other address or number as may be notified hereunder by that
          party from time to time for this purpose and shall be effectual
          notwithstanding any change of address or facsimile number not so
          notified and a copy of all notices given by the Landlord to Virata
          Limited shall be sent to the Tenant's Solicitors Taylor Vinters of
          Merlin Place Milton Road Cambridge (Reference SB/TLF) or such other
          firm of solicitors in England and Wales as the Tenant may notify to
          the Landlord in writing from time to time) provided that this
          requirement shall not in any way affect the effective service of any
          notice on Virata Limited

     (b)  each such notice shall be deemed to have been given or delivered if by
          letter twenty four hours after posting it if by delivery when left at
          the relevant address and if by facsimile when transmitted

7.8  Disputes: any dispute arising between the Tenant and any owner or occupier
     of any adjoining or neighbouring land or premises as to any easement quasi-
     easement right or privilege in connection with the Demised Premises and any
     adjoining and neighbouring land or premises or as to any party or other
     wall shall be determined by the Landlord's Surveyor for the time being
     (acting reasonably) whose decision shall (save as to points of law or
     manifest error) be final and binding on the Tenant

7.9  Removal of Tenant's Goods: if at such time as the Tenant has vacated the
     Demised Premises after the determination of the Term either by effluxion of
     time or otherwise any property of the Tenant shall remain in or on the
     Demised Premises and the Tenant shall fail to remove the same within seven
     days after being requested by the Landlord so to do by a notice in that
     behalf then and in such a case the Landlord may as the agent of the

                                       42
<PAGE>

     Tenant (and the Landlord is hereby appointed by the Tenant to act in that
     behalf) sell such property and shall then hold the proceeds of sale after
     deducting the costs and expenses of removal storage and sale reasonably and
     properly incurred by it to the order of the Tenant PROVIDED THAT the Tenant
     will indemnify the Landlord against any liability incurred by it to any
     third party whose property shall have been sold by the Landlord in the bona
     fide mistaken belief (which shall be presumed unless the contrary be
     proved) that such property belongs to the Tenant and was liable to be dealt
     with as such pursuant to this sub-clause

7.10 Waiver of Breach: no demand for or receipt of rent or other payment whether
     paid by direct debit standing order or otherwise by the Landlord after
     notice or knowledge by the Landlord or its personnel of any breach of any
     of the Tenant's covenants shall operate as a waiver wholly or partially of
     such breach and the Tenant shall not be entitled to set up such demand or
     receipt as a defence in any action or proceeding by the Landlord

7.11 Occupation after Expiry: if and so long as the Tenant shall remain in
     occupation of the Demised Premises or any part thereof after the expiry of
     the Term (howsoever occurring) the Tenant shall pay to the Landlord on the
     usual quarter days a sum equal to the rent and any other monies which would
     have been due had the term subsisted but no new Lease or extension of the
     Term thereof shall be created or implied thereby

7.12 Governing law and submission to jurisdiction : This Lease shall be governed
     by and construed in accordance in all respects with the laws of England and
     Wales and the Landlord the Tenant hereby irrevocably submits to the non-
     exclusive jurisdiction of the English Courts and consent to service of
     process by post or in any other manner permitted by English law

7.13 Superior Landlord: any approval or consent required of the Landlord and any
     easement right power or discretion excepted reserved or available to the
     Landlord by this Lease shall be deemed in addition to require the consent
     of and to except reserve and make the same available to any mortgagee and
     any superior landlord and any costs and expenses of the Landlord payable by
     the Tenant by virtue of this Lease shall include all costs and expenses
     that any superior landlord or mortgagee can recover from the Landlord
     PROVIDED THAT in the case of any such superior landlord there shall not be
     implied

                                       43
<PAGE>

     any obligation to act reasonably in giving its consent unless the superior
     landlord is required to do so under the terms of the Superior Lease

7.14 Exclusion of Compensation:

     (a)  Unless any statutory provision prohibits or modifies the Tenant's
          right to compensation being excluded or reduced by agreement neither
          the Tenant nor any undertenant (whether immediate or derivative) shall
          be entitled to claim any compensation from the Landlord under the
          Landlord and Tenant Act 1954 on quitting the Demised Premises or any
          part thereof

     (b)  The Tenant shall not be entitled to claim any compensation from the
          Landlord arising from the reasonable exercise of its rights of entry
          onto the Demised Premises in accordance with the provisions of this
          Lease

7.15 Release of Reversioner: On receipt of any application from any person who
     at any time prior to the date of such application was entitled to the
     reversion immediately expectant upon the term granted by this Lease for the
     release of any covenant in respect of the whole or any part of the Property
     the Tenant shall consent (and shall not serve any notice objecting to) such
     release

7.16 Commencement: For the avoidance of doubt the provisions of this deed (other
     than those contained in this Clause) shall not have any effect until this
     deed has been dated

7.17 Tenancy: This Lease granted in pursuance of an Agreement dated 19th day of
     December 2000 is a new tenancy for the purposes of Section 1 of the
     Landlord and Tenant (Covenants) Act 1995

7.18 Contracts (Rights of Third Parties) Act 1999: It is hereby agreed and
     declared that no person who is not a party to this Lease (other than an
     assignee of the Tenant) shall be entitled to enforce in its own right any
     term of this Lease pursuant to the Contracts (Rights of Third Parties) Act
     1999

8.   SERVICE CHARGE

                                       44
<PAGE>

     The Landlord and the Tenant covenant one with the other AND IT IS HEREBY
     AGREED as follows:

8.1  The Tenant shall pay to the Landlord without any deduction by way of
     further and additional rent the Service Charge

8.2  The Landlord shall be entitled to include as part of the costs of the
     Landlord's services a reasonable proportion of all such costs expenses and
     outgoings which are of a periodically recurring nature whenever disbursed
     incurred or made and which relate to any period of occupation by the Tenant
     or any undertenant including a sum or sums of money to provide for
     reasonable anticipated expenditure as the Landlord may reasonably allocate
     to the year in question as being fair and reasonable in the circumstances
     and to collect a sum or sums of money for expenditure which is
     unanticipated at the commencement of the Accounting Year

8.3  The Tenant shall on each of the quarter days for payment of the rent first
     hereby reserved pay by equal quarterly payments in advance to the Landlord
     such sum in advance and on account of the Service Charge as the Landlord
     shall specify at the commencement of the Landlord's Accounting Year at its
     discretion to be a fair and reasonable interim payment in accordance with
     the principles of good estate management

8.4  As soon as practicable after the end of the Landlord's Accounting Year or
     part of a year the Landlord shall supply the Tenant with a copy of a
     Schedule certified by the Landlord's accountant or managing agent
     containing a summary of the costs of the Landlord's services in respect of
     the Landlord's Accounting year or part of a year and showing the Service
     Charge payable by the Tenant for the year in question (due credit being
     given for all interim payments made by the Tenant during the year or part
     of a year in question) and there shall be paid by the Tenant to the
     Landlord within 14 days of demand the amount of the Service Charge as
     aforesaid then owing (if any) or any balance then found due and payable or
     (as the case may require) there shall be allowed by the Landlord to the
     Tenant against the Tenant's liability for service charge for the next year
     any amount which may have been overpaid by way of interim payments (and at
     the end of the Term (howsoever determined) the Landlord shall account and
     pay to the Tenant

                                       45
<PAGE>

     any sums paid by way of interim payments on account of Service Charge owing
     to the Tenant in respect of the final service charge year

8.5  Every certificate of the Landlord's accountant or managing agent as to the
     cost of the Landlord's services or as to any sum payable by the Tenant
     hereunder shall (save as to points of law and manifest error) be final and
     binding on the Landlord and the Tenant and every such certificate shall be
     in writing

8.6  Any omission by the Landlord to include in any year a sum expended or a
     liability incurred in that year shall not preclude the Landlord from
     including such sum or the amount of such liability in any subsequent year
     or years as the Landlord shall deem fit

8.7  The provision of this Clause shall continue to apply notwithstanding the
     expiration or sooner determination of the Term (though only in respect of
     the period up to such expiration or sooner determination)

8.8  The Landlord may withhold and extend or vary the Landlord's services or any
     of them from time to time if the Landlord deems it necessary so to do in
     the interests of good estate management

9.   SURETY COVENANTS

     In consideration of the demise contained in this Lease having been made at
     the Surety's request the Surety hereby covenants with the Landlord in the
     terms of the Seventh Schedule


IN WITNESS whereof the parties to this Deed being companies have caused their
respective Common Seals to be hereunto affixed and being individuals have
hereunto set their hands and seals the day and year first before written

                                       46
<PAGE>

                              THE FIRST SCHEDULE
                            (The Demised Premises)

All those premises comprising the building known or to be known as Unit 230
Cambridge Science Park  Milton Road  Cambridge as the same are shown for
identification on Plan 1 and thereon edged red being part of the land registered
under Title Number CB 121576 and are shown by way of further identification on
Plans 2 and 3

                              THE SECOND SCHEDULE
                     (Easements and other rights granted)

Subject to compliance with any existing or future regulations relating thereto
promulgated by the Landlord from time to time and in common with the Landlord
and all other persons having similar rights:

1.   The right (so far as the Landlord has power to grant the same) of passage
     and running of the Services from and to the Demised Premises through the
     Conduits in or through the Estate provided that the Landlord may at any
     time alter the route of any such Conduits on not less than two weeks prior
     notice (save in case of emergency) and the minimum disturbance is caused to
     the Tenant

2.   The right to pass and repass at all times with or without vehicles from and
     to the public highway and the loading areas and the waste compactor which
     the Tenant is entitled to use from and to the Demised Premises over and
     along the roads and accessways of the Common Parts of the Estate provided
     that the Tenant shall not cause or permit any vehicles or trailers to be
     parked thereon

3.   The right to keep a waste compactor in such area as the Landlord may
     designate and in the manner to be approved by the Landlord

4.   The right to exclusive use of 123 car parking spaces shown edged yellow on
     Plan 1

                                       47
<PAGE>

5.   The right to provide a sheltered bike rack of a design to be first approved
     in writing by the Landlord (such approval not to be unreasonably withheld
     or delayed) in the area shown edged yellow on Plan 1 (or such other area as
     the Landlord shall have first approved in writing (such approval not to be
     unreasonably withheld and delayed)) for up to a maximum of 50 bicycles

6.   The right on prior written notice (except in an emergency) to enter on to
     other parts of the Estate together with work people and materials to
     connect into and repair the Conduits serving the Demised Premises and for
     the proper performance of the Tenant's covenants herein contained the
     person or persons exercising such right making good all physical damage to
     the Estate thereby occasioned

7.   The benefit of rights granted by or referred to in the deeds and documents
     mentioned in the Fifth Schedule insofar as the same are still subsisting
     and capable of taking effect and affect the Demised Premises

8.   Subject to the prior written approval of the Landlord under the Superior
     Lease the right to have the name or trading name of the Tenant displayed on
     any common signboard for the Estate

                              THE THIRD SCHEDULE
                         (Exceptions and Reservations)
                  In favour of the Landlord and its personnel
                   and all other persons authorised by it or
                who now have or may hereafter be granted by the
                            Landlord similar rights

1.   The full free and uninterrupted passage and running of the Services to and
     from any adjoining or neighbouring property and the buildings now or
     hereafter to be erected thereon and for the benefit of the respective
     owners lessees or occupiers for the time being thereof through the Conduits
     which now are or may hereafter be in upon over or under the Demised
     Premises

                                       48
<PAGE>

2.   The full and free right and liberty to enter after giving not less than two
     working days prior written notice (except in an emergency when no notice
     shall be required) upon the Demised Premises at all times for the purpose
     of connecting laying inspecting repairing cleansing maintaining amending
     altering replacing relaying or renewing the Conduits referred to in
     Paragraph 1 of this Schedule the person or persons exercising such right
     making good all physical damage to the Demised Premises thereby occasioned
     to the reasonable satisfaction of the Tenant but without any liability to
     pay any compensation

3.   The full right and liberty to rebuild or execute alterations repairs and
     other works upon or to any adjoining or neighbouring property in such
     manner as the Landlord or the person or persons exercising such right may
     think fit notwithstanding any interferences with or reasonable damage
     caused thereby to the Demised Premises or to the access or enjoyment of
     light or air to or in respect of the Demised Premises or that such
     rebuilding or alterations repairs and other works shall temporarily
     interfere with the use or occupation of the Demised Premises the person or
     persons exercising such right making good all physical damage to the
     Demised Premises thereby occasioned to the reasonable satisfaction of the
     Tenant but without any liability to pay any compensation

4.   The full and free right and liberty accompanied by a member of the Tenant's
     staff to enter (after not less than two working days prior notice (except
     in an emergency when no notice shall be required) and then without having
     to be attended by a member of the Tenant's staff) upon the Demised Premises
     at all times:

     (a)  in order to clean decorate repair alter or rebuild any adjoining or
          neighbouring premises and/or to repair maintain or renew the
          Irrigation System

     (b)  for any other purpose in connection with the performance of the
          Landlord's rights and obligations under the Lease

     on completion of any of such works the person or persons exercising such
     right or rights making good all physical damage to the Demised Premises
     thereby occasioned to the

                                       49
<PAGE>

     reasonable satisfaction of the Tenant and causing as little inconvenience
     as possible but without any liability to pay compensation

5.   The full and free right and liberty to use the Irrigation System

6.   The full and free right of support shelter and protection and all other
     easements and rights now or hereafter belonging to or enjoyed by any
     adjoining or neighbouring property

7.   All rights of light and air and all other easements and rights now or
     hereafter belonging to or enjoyed by any adjoining or neighbouring property
     over the Demised Premises

8.   Right in the case of fire or other emergency to enter upon the Demised
     Premises with or without all necessary workmen equipment and materials to
     execute and take all necessary or desirable measures and precautions the
     person or persons exercising such right or rights making good all physical
     damage to the Demised Premises thereby occasioned to the reasonable
     satisfaction of the Tenant and causing as little inconvenience as possible
     but without any liability to pay any compensation

9.   The rights granted by or referred to in the deeds and documents mentioned
     in the Fifth Schedule insofar as these are still subsisting and relate to
     the Demised Premises

PROVIDED ALWAYS AND IT IS HEREBY AGREED AND DECLARED that (as appropriate) all
the foregoing provisions of this Schedule as regards anything not in being at
the date hereof shall apply and be effective only during the shorter of the
following periods namely the duration of the Term or eighty years from the date
hereof

                              THE FOURTH SCHEDULE
                  (Particulars of the Landlord's services and
                                 other matters
                 in respect of which the Tenant is to pay the
                                Service Charge)

1.   The Common Parts

                                       50
<PAGE>

     Inspecting repairing decorating renewing rebuilding replacing cleansing
     lighting and maintaining the Common Parts and the party structures of the
     Estate

2.   Common Facilities

     Making repairing maintaining decorating and cleansing and (where necessary)
     rebuilding or renewing all areas party structures conduits or other items
     whatsoever which may belong to or be capable of  being used or enjoyed by
     the Estate in common with any other property or properties

3.   Staff

3.1  Providing staff for the day to day running of the Estate and the
     installations therein including (but without prejudice to the generality of
     the foregoing) cleaning and maintenance and for the general management and
     security of the Estate

3.2  Providing repairing maintaining decorating heating and lighting any
     accommodation and facilities for the Estate management staff within the
     Estate

3.3  Providing repairing and replacing all tools appliances materials and
     equipment for the proper performance of the duties of any such staff
     including uniforms and other working clothes

4.   Insurance

     Insuring and keeping insured the Common Parts of the Estate in accordance
     with the Landlord's covenant hereinbefore contained against the Insured
     Risks (including any insurance valuation fees) and effecting or maintaining
     insurance in respect of any public third party and employers' liability of
     the Landlord arising out of or in connection with any matter involving or
     relating to the Estate and any other insurance properly maintained by the
     Landlord in respect of the Estate

                                       51
<PAGE>

5.   Open Areas and Waste Disposal

5.1  Keeping any parts of the Estate which are unbuilt upon clear of all rubbish
     and free from weeds and in a neat and tidy condition and (as may be
     appropriate) the cost of keeping all grassed areas regularly mown all
     borders properly stocked and tended and all trees properly lopped topped
     and pruned

5.2  Providing maintaining repairing and renewing any compacting equipment
     dustbins or similar receptacles and equipment for refuse for the Estate and
     removal and disposal of refuse from the Estate

5.3  Providing maintaining repairing and renewing such seats benches trees
     shrubs flowers grass and other plants and landscaped areas water equipment
     flags flag poles or other like amenities as the Landlord shall at its
     discretion provide for the benefit of the tenants on the Estate and the
     amenity of the Common Parts

6.   Rates and Services

6.1  Paying all general and water rates and all other existing and future rates
     taxes duties charges assessments and outgoings whatsoever (whether
     parliamentary parochial local or of any other description) for the time
     being payable in respect of the Common Parts of the Estate

6.2  Paying the costs for the provision of the services in respect of the Common
     Parts of the Estate

7.   Statutory Requirements

7.1  Paying the costs of and incidental to the compliance by the Landlord with
     every notice regulation or order of any competent or local or other
     authority in relation to the Common Parts of the Estate

                                       52
<PAGE>

7.2  Paying the proper costs of taking all or any steps deemed by the Landlord
     to be desirable or expedient for complying with making representations
     against or otherwise contesting the incidence of the provisions of any
     legislation or orders or statutory requirements thereunder concerning town
     planning public health public highways streets drainage or other matters
     relating or alleged to relate to the Estate for which the Tenant or other
     tenants of the Estate are not directly liable under the terms of the demise
     to them

8.   Signs

8.1  Providing and maintaining advertisements directional signs and other
     hoardings (if any) relating to the Estate as a whole or any part whether
     inside or outside the boundaries of the Estate

8.2  Providing and maintaining (at the Landlord's discretion) a signboard for
     the Estate giving the names and positions of occupiers of units within the
     Estate

9.   Security

     Providing (at the discretion of the Landlord) maintaining repairing and
     replacing such security measures and devices (including burglar alarms
     close circuit television and surveillance systems)  for the Estate as the
     Landlord may deem to be necessary or desirable in the interests of good
     estate management

10.  Car Parking

     Managing and maintaining the car parking areas within the Estate including
     installation repair and renewal of all barriers and other installations
     therein and keeping the same open for use by those visiting the Estate

                                       53
<PAGE>

11.  Lighting to Roadways and Pathways

     Lighting those parts of the roadways and pathways forming part of the
     Common Parts which it is appropriate to light between such times as the
     Landlord shall properly determine including insurance maintenance servicing
     repair and decoration of the lighting system

12.  Management Charges

     All proper fees charges expenses and commissions of any accountants
     surveyors and all proper fees of architects solicitors or any professional
     advisors whom the Landlord may from time to time employ to manage and/or
     supervise the Estate on its behalf together with the fees and expenses
     incurred in preparing accounts and certificates of the costs of the
     Landlord's services.  In the event of the Landlord deciding in its absolute
     discretion at any time or from time to time not to employ agents to manage
     and/or supervise the Estate as aforesaid then the Landlord shall be
     entitled instead to include as part of the costs of the Landlord's services
     a management fee to cover the costs of the Landlord (to include a sum for
     overheads) in the management and supervision of the Estate generally
     including (but without prejudice to the generality of the foregoing) the
     carrying out of the matters referred to in this Schedule and the
     ascertainment of the amount of the costs of the Landlord's services and
     their apportionment between the tenants of units in the Estate and for the
     avoidance of doubt (but without prejudice to the Landlord's right to
     recover the costs of recovering rent pursuant to the terms of this Lease)
     the Tenant shall not be obliged to pay any fees levied for the collection
     of rent by way of service charge

13.  The Estate

     A fair and proper proportion to be determined by the Landlord's Surveyor
     (whose decision shall be final and binding) of all costs incurred by or
     payable by the Landlord in connection with services or supplies insofar as
     they relate to the Estate and/or any other services or supplies in
     connection with the Estate whether relating to the Common Parts or
     otherwise

                                       54
<PAGE>

14.  Superior Lease

     A fair and proper proportionate part of the rents specified in the Second
     Part of the Third Schedule to the Superior Lease paid by the Landlord to
     the Superior Landlord (other than the moneys referred to in paragraph (3)
     of the Second Part of the Third Schedule to the Superior Lease)

15.  General

     Any other services supplies and works as the Landlord may deem desirable or
     necessary in the interests of good estate management for the benefit of the
     Estate or any part thereof or the lessees tenants or occupiers thereof or
     for securing or enhancing any amenity of or within the Estate

                              THE FIFTH SCHEDULE
                  (Deeds and Documents affecting the Demised
                                   Premises)

<TABLE>
<CAPTION>

Date               Description of Document          Parties
<S>                <C>                              <C>

27.03.90           Lease (hereinbefore defined as   (1) The Master Fellows and Scholars of
                   the "Superior Lease") (Phase         the College of the Holy and Undivided
                   II) as varied by                     Trinity within the Town and University
                                                        of Cambridge of King Henry VIII's
                                                        Foundation
                                                    (2) The General Electric Company plc

05.11.92           Deed of Variation                (1) The Masters Fellows and Scholars of
                                                        Trinity College Cambridge
                                                    (2) The Equitable Life Assurance Society

</TABLE>

                                       55
<PAGE>

<TABLE>
<S>                <C>                              <C>
26.06.84           Section 52 Agreement             (1) South Cambridgeshire District
                                                        Council
                                                    (2) The Master Fellows and Scholars of
                                                        the College of the Holy and Undivided
                                                        Trinity within the Town and University
                                                        of Cambridge of King Henry the VIII's
                                                        Foundation

                   Title Number CB121576
</TABLE>

                              THE SIXTH SCHEDULE
                            Covenants by the Surety

1.   The Surety  hereby irrevocably and unconditionally GUARANTEES to the
     Landlord as a continuing guarantee the payment when due of all sums due
     owing or outstanding from the Tenant to the Landlord under this Lease and
     the due performance by the Tenant of the Tenant's Covenants and  agrees to
     indemnify the Landlord from and against all loss damage costs and expenses
     which the Landlord may suffer through or arising from any failure by the
     Tenant to perform any of the Tenant's Covenants or any failure by the
     Tenant duly fully and punctually to pay any such sum or any other sum
     required to be paid by it in relation to or otherwise to perform its said
     obligations

2.   The Surety HEREBY FURTHER COVENANTS irrevocably and unconditionally with
     the Landlord that if the Tenant shall become Insolvent and/or this Lease is
     vested in the Crown as bona vacantia and/or this Lease is disclaimed and/or
     forfeited and/or the Term is otherwise determined prior to its contractual
     expiry the Surety will (if so required by the Landlord within six months of
     the Landlord learning of the relevant event) accept from and execute and
     deliver to the Landlord a counterpart of a new lease of the Demised
     Premises for a term commencing on the date of such disclaimer or other
     event putting an end to the effect of this Lease as aforesaid and
     continuing for the residue then remaining unexpired of the Term the Surety
     to be responsible for the costs of both parties in

                                       56
<PAGE>

     connection with such new lease (together with any Value Added Tax payable
     thereon) and to reserve the same rents and other sums as are then reserved
     and made payable by this Lease and to be subject to the same covenants
     conditions and provisions (including the provisions for the review of rent
     at the times and in manner contained in this Lease) as are contained in
     this Lease

3.   All sums payable hereunder by the Surety shall be paid immediately on
     demand by the Landlord in full without any deduction withholding counter-
     claim or set off and if the  Surety is compelled by law to make any
     deduction or withholding from any such sums or if any payment hereunder
     shall be or become subject to any tax duty levy or impost of any nature
     (whether before or after the same has been paid to the Landlord) excluding
     any tax (other than Value Added Tax) assessable on the Landlord in respect
     of any income from the Demised Premises the  Surety shall (insofar as
     permitted by law) immediately pay to the Landlord such additional amount or
     amounts as will result in payment to and retention by the Landlord of the
     full amount which would have been received and retained by the Landlord but
     for such deduction or withholding or the imposition of such tax duty levy
     or impost

4.   Without prejudice to the Landlord's rights against the Tenant as between
     the Landlord and the Surety the Surety shall be liable hereunder as if it
     were solely and principally liable and not merely a surety and its
     liability hereunder shall not be released discharged or diminished by:

     (a)  any legal limitation lack of capacity or authorisation or defect in
          the actions of the Tenant in relation to any invalidity or
          unenforceability of or any variation (whether or not agreed by the
          Surety) of any of the terms of this Lease the insolvency (or in the
          case of an individual Tenant death) of the Tenant or any change in the
          Tenant's identity constitution status or control; or

     (b)  any forbearance neglect or delay in seeking performance of the
          obligations of the Tenant  any granting of time indulgence or other
          relief to the Tenant in relation

                                       57
<PAGE>

          to such performance or any composition with discharge waiver or
          release of the Tenant; or

     (c)  any other act omission fact or circumstance which might otherwise
          release discharge or diminish the liability of a guarantor

5.   Any release settlement or discharge between the Landlord and the Surety
     shall be conditional upon no security or payment made or given to the
     Landlord being avoided reduced set aside or rendered unenforceable by
     virtue of any provision or enactment now or hereafter in force relating to
     bankruptcy insolvency or liquidation and if any such security or payment
     shall be avoided reduced set aside or rendered unenforceable the Landlord
     shall be entitled to recover the full amount or value of any such security
     or payment from the Surety and otherwise to enforce this Schedule as if
     such release settlement or discharge had not taken place

6.   This guarantee is given to the Landlord by the Surety under seal and shall
     enure for the avoidance of doubt not merely for the benefit of the Landlord
     but for the benefit of any successor in title (however such title devolves)
     of the Landlord

7.   The  Surety HEREBY FURTHER COVENANTS  with the Landlord

     (a)  to notify the Landlord from time to time in writing forthwith of any
          change (in the case of a company) to the registered office of the
          Surety or (in the case of an individual) to the address of the Surety
          and any notice request application consent approval or other
          notification served by the Landlord on the Surety shall be deemed to
          have been given or delivered  if by letter forty eight hours after
          posting it if by delivery when left at the relevant address and shall
          be effectual notwithstanding any change of address not so notified

     (b)  to submit to the jurisdiction of Courts in England and Wales and to
          accept service of document notice proceedings or otherwise at the
          address in England and Wales set out on page one of this Lease

                                       58
<PAGE>

     (c)  to keep the Landlord fully and effectually indemnified from and
          against all actions demands claims liabilities losses damages costs
          and expenses whatsoever (including all interest penalties legal and
          other costs and expenses together with Value Added Tax thereon if
          applicable) arising directly or indirectly through the failure or
          omission by the Surety  to comply with paragraphs 7(a) and 7(b) above

EXECUTED as a DEED by                       )
                     as the                 )
Attorney of The Equitable Life Assurance    )
Society (in exercise of a Power of Attorney )
executed as a Deed dated 6 March 2001) in   )
the presence of:                            )

NAME
ADDRESS

OCCUPATION

                                       59
<PAGE>

                              (THE COMMON SEAL of VIRATA
                              (LIMITED was hereunto affixed in the
                              (presence of:


                                  Director



                                  Secretary


                              (EXECUTED as a DEED by VIRATA
                              (CORPORATION

                                       60