<PAGE>   1
                                                                   EXHIBIT 10.27

                      Dated the ___ day of __________ 2000

                          DERAMORE HOLDINGS LIMITED (1)

                                       and

                      PIVOTAL CORPORATION (NI) LIMITED (2)

                                       and

                             PIVOTAL CORPORATION (3)

                                      LEASE
                                       of

                           Third Floor, Capital House,
                         3 Upper Queen Street, Belfast.


                                 KEARNEY SEFTON
                                   Solicitors,
                              12 Brunswick Street,
                                    BELFAST,
                                    BT2 7GE


<PAGE>   2

                    LEASE: Dated    day of             2000

<TABLE>
<S>     <C>     <C>                         <C>
1.      PARTICULARS

        1.1.1   The Landlord                DERAMORE HOLDINGS LIMITED
                                            having its registered office at
                                            160 Brompton Road, Knightsbridge,
                                            London SW3 1RP

        1.1.2   The Tenant                  PIVOTAL CORPORATION (NI) LIMITED
                                            having its registered office at
                                            50 Bedford Street, Belfast, BT2 7FU

        1.1.3   The Guarantor               PIVOTAL CORPORATION having its
                                            registered office at
                                            224 West Esplanade, Suite 300 North,
                                            Vancouver, British Columbia,
                                            VYM 3M6, Canada

        1.2     The Building                The building (including the car
                                            park and yard to the rear thereof)
                                            known as Capital House,
                                            3 Upper Queen Street, Belfast shown
                                            (for the purposes of identification
                                            only) edged [blue] on the Plan

        1.3     The Premises                The third floor of the Building as
                                            the same is more particularly
                                            defined in the First Schedule

        1.4     Total Lettable Area         9,648 square feet
                of the Premises

        1.5     Term                        10 years from and including the
                                            17th day of April 2000 subject to
                                            clause 10.16

        1.6.1   First Rent Commencement     17th day of May 2000
                Date
</TABLE>

                                      -1-
<PAGE>   3


<TABLE>
<S>     <C>     <C>                         <C>
        1.6.2   Second Rent Commencement    17th day of October 2000
                Date

        1.7     Initial Rent                Pound Sterling 115,776.00 per annum.

        1.8     Review Date                 17th day of April 2005

        1.9     Interest Rate               4% per cent per annum above
                                            the Base Rate of the Bank of
                                            Ireland (or some other bank
                                            nominated in writing from time
                                            to time by the Landlord)

        1.10    Permitted Hours             7am to 7pm Monday to Friday
                                            inclusive

        1.11    Decorating Year             2005

        1.12    Service Charge              the amount referred to in clause 7.4

        1.13    Insurance Rent              a reasonable proportion (as
                                            determined by the Surveyor) of
                                            the sums which the Landlord
                                            shall from time to time reasonably
                                            pay by way of premiums for
                                            insuring the Building against the
                                            risks set out in clauses 8.3(a), (b)
                                            and (d),

                                            (b) all of any increased premium
                                            payable by any act or omission of
                                            the Tenant or by the user carried
                                            out by the Tenant on the Premises,
                                            and

                                            (c) all the reasonable premium
                                            that the Landlord shall from time
                                            to time pay (or where such
                                            insurance includes other premises,
                                            a reasonable proportion of such
                                            premium to be determined by the

</TABLE>


                                      -2-
<PAGE>   4
<TABLE>
<S>     <C>     <C>                         <C>
                                            Surveyor acting as an expert and not
                                            as an arbitrator) for insuring
                                            against the loss of Rent and Service
                                            Charge in accordance with
                                            clause 8.3(c).

</TABLE>

2.      DEFINITIONS

        2.1     The terms defined in this clause and in the Particulars shall
                for all purposes of this Lease have the meanings specified.

        2.2     'the Plan' means the plan and drawings referred to in the First
                Schedule and annexed to this Lease.

        2.3     'Rent' means the Initial Rent and the rents ascertained in
                accordance with the Fourth Schedule and such term includes
                neither the Service Charge nor the Insurance Rent but the term
                'rents' includes Rent, the Service Charge, and the Insurance
                Rent.

        2.4     'Pipes' means pipes, sewers, drains, mains, ducts, conduits,
                gutters, watercourses, wire cables, channels, subways, flues and
                all other conducting media, including any fixings, louvres,
                cowls and other covers.

        2.5     'the Services' mean the services set out in the Sixth Schedule.

        2.6     'the Annual Expenditure' means:

                (a)     all reasonable costs expenses and outgoings whatsoever
                        reasonably incurred by the Landlord in providing all or
                        any of the Services; and

                (b)     all sums reasonably incurred by the Landlord in relation
                        to the items set out in the Seventh Schedule;

                and any VAT payable thereon ('the Costs') (including any of the
                Costs incurred by a third party such as (without prejudice to
                the generality of the foregoing) the Surveyor or the managing
                agents where the Costs have been incurred for and on behalf of
                the Landlord and where the Landlord is liable to re-imburse the
                third party for the Costs) Provided that the Annual Expenditure
                shall not include any costs for the Building with respect to the
                employment of security staff at the main entrance to the
                Building outside the hours from 6.30a.m. to 7.30p.m.



                                      -3-
<PAGE>   5



                Monday to Friday inclusive save where the Landlord reasonably
                incurs such security costs outside the aforesaid hours acting in
                accordance with the principles of good estate management.

        2.7     'the Common Parts' mean the entrance halls, landings, lift
                shafts, staircases, passages, service yard, car park and any
                other areas which are from time to time during the Term provided
                by the Landlord for common use and enjoyment by the tenants and
                occupiers of the Building and all persons expressly or by
                implication authorised by them.

        2.8     'the Retained Parts' mean all parts of the Building not let or
                intended to be let to a tenant including (but without prejudice
                to the generality of the foregoing):

                (a)     the Common Parts;

                (b)     office accommodation for security and any ancillary
                        staff;

                (c)     all Pipes in on or serving the Building except any that
                        are within and solely serve premises let or intended to
                        be let;

                (d)     such parts of the Building including (again without
                        prejudice to the generality of the foregoing) those
                        parts of the walls foundations and roofs not let or
                        intended to be let to a tenant;

                (e)     the windows and window frames serving the Premises.

        2.9     'Interest' means interest during the period from the date on
                which the payment is due to the date of payment, both before and
                after any judgment, at the Interest Rate then prevailing or
                should the Base Rate referred to in clause 1.9 cease to exist,
                such other rate of interest as is most closely comparable with
                the Interest Rate to be agreed between the parties or in default
                of agreement to be determined by the Accountant acting as an
                expert and not as an arbitrator.

        2.10    'the Planning Acts' means the Planning (Northern Ireland) Order
                1991 and all statutes regulations and orders included by virtue
                of clause 3.14.

        2.11    'Insured Risk' means any risk against which the Landlord shall
                at the time of the damage or destruction in question have
                effected insurance.



                                      -4-
<PAGE>   6


        2.12    'the Office Covenants' mean the covenants set out in the Fifth
                Schedule.

        2.13    'the Surveyor' means any suitably qualified person or firm
                appointed by or acting for the Landlord (including an employee
                of the Landlord or a Group Company and including the person or
                firm appointed by the Landlord to collect the rents and manage
                the Building) to perform the function of a surveyor for any
                purpose of this Lease.

        2.14    'the Accountant' means any suitably qualified person or firm
                appointed by or acting for the Landlord (including an employee
                of the Landlord or a Group Company and including the person or
                firm appointed by the Landlord to collect the rents and manage
                the Building) to perform the function of an accountant for the
                purpose of this Lease.

        2.15    'Adjoining Property' means any neighbouring or adjoining land or
                property in which the Landlord or a Group Company has a freehold
                or leasehold interest or in which during the Term the Landlord
                (or a Group Company) shall have acquired a freehold or leasehold
                interest.

        2.16    'the Other Buildings' shall mean all buildings now or at any
                time during the Term erected on the Adjoining Property.

        2.17    'the 1996 Order' means the Business Tenancies (Northern Ireland)
                Order 1996.

        2.18    'Group Company' means a company that is a member of the same
                Group as the Landlord within the meaning of article 31 of the
                1996 Order.

3.      INTERPRETATION

        3.1     The expressions 'the Landlord' and 'the Tenant' wherever the
                context so admits include their reactive successors in title.

        3.2     Where the Landlord the Tenant or the Guarantor for the time
                being are two or more individuals the terms 'the Landlord', 'the
                Tenant' and 'the Guarantor' include the plural number and
                obligations expressed or implied to be made by or with such
                party are deemed to be made by or with such individuals jointly
                and severally.



                                       -5-

<PAGE>   7


        3.3     Words importing the one gender include all other genders and
                words importing the singular include the plural and vice versa.

        3.4     The expression 'the Guarantor' includes any person who enters
                into covenants with the Landlord pursuant to clause 5.21.

        3.5     The expression 'the Term' in relation to clause 9 includes any
                period of holding over or extension or continuance thereof
                whether by statute or common law and elsewhere in this Lease the
                said expression includes such period where the context so
                admits.

        3.6     References to 'the last year of the Term' include the last year
                of the Term if the same shall determine otherwise than by
                effluxion of time and to 'the expiration of the Term' include
                such sooner determination of the Term

        3.7     References to any right of the Landlord to have access to the
                Premises shall be construed as extending to all persons properly
                authorised by the Landlord (including agents, professional
                advisers, contractors, workmen and others).

        3.8     References to 'the Premises' in the absence of any provision to
                the contrary include any part thereof.

        3.9     Any covenant by the Tenant not to do an act or thing shall be
                deemed to include an obligation not to permit such act or thing
                to be done and to use all reasonable endeavours to prevent such
                act or thing being done by a third party.

        3.10    Whenever the consent or approval of the Landlord is required or
                requested in relation to this Lease, such provisions shall be
                construed as also requiring the consent or approval of any
                mortgagee of the Premises where the same shall be required
                except that nothing in this Lease shall be construed as implying
                that any obligation is imposed upon any mortgagee not
                unreasonably to refuse any such consent.

        3.11    References to 'consent of the Landlord' or words to similar
                effect mean a consent in writing signed by or on behalf of the
                Landlord and to 'approved' and 'authorised' or words to similar
                effect mean (as the case may be) approved or authorised in
                writing by or on behalf of the Landlord.



                                      -6-
<PAGE>   8

        3.12    The terms 'the parties' or 'party' shall mean the Landlord
                and/or the Tenant but except where there is an express
                indication to the contrary shall exclude the Guarantor.

        3.13    'Development' has the meaning given by Article 11 of the
                Planning (Northern Ireland) Order 1991.

        3.14    Any reference to a specific statute includes any statute which
                that statute has directly or indirectly replaced (with or
                without modification) and any statutory extension or
                modification or re-enactment of such statute and any regulations
                or orders made thereunder and any general reference to 'statute'
                or 'statutes' includes any regulations or orders made
                thereunder.

        3.15    The paragraph headings do not form part of this Lease and shall
                not be taken into account in its construction or interpretation.

4.      DEMISE

        The Landlord DEMISES to the Tenant the Premises TOGETHER WITH the rights
        specified in the Second Schedule but EXCEPTING AND RESERVING to the
        Landlord the rights specified in the Third Schedule TO HOLD the Premises
        to the Tenant for the Term SUBJECT TO all rights easements privileges
        restrictions covenants and stipulations of whatever nature affecting the
        Premises YIELDING AND PAYING to the Landlord:

        (a)     the Rent, payable without any deduction by equal quarterly
                payments in advance on the first days of February, May, August
                and November in every year, and proportionately for any period
                of less than a year, a proportionate sum in respect of the
                period from and including the Second Rent Commencement Date to
                and including the day before the quarter day next thereafter to
                be paid on the Second Rent Commencement Date Provided Always
                that the Tenant shall pay an abated Rent at the rate of Pounds
                Sterling 54,996.00 per annum for the period from and including
                the First Rent Commencement Date to the day immediately prior to
                the Second Rent Commencement Date, such abated Rent to be
                payable without any deduction by equal quarterly payments in
                advance on the aforesaid quarter days, and proportionately for
                any period of less than a year, the first such payment being a
                proportionate sum in respect of the period from and including
                the First Rent Commencement Date to and including the day



                                      -7-
<PAGE>   9

                before the quarter day next thereafter to be paid on the First
                Rent Commencement Date hereof, and

        (b)     by way of further rent, the Service Charge payable on demand in
                accordance with clause 7 and the Insurance Rent payable on
                demand in accordance with clause 8.

5.      The Tenant COVENANTS with the Landlord:

        Rent

        5.1     To pay the rents on the days and in the manner set out in clause
                4.

        Outgoings and VAT

        5.2     To pay and to indemnify the Landlord against:

                (a)     all rates, taxes, assessments, duties, charges,
                        impositions and outgoings which are now or during the
                        Term shall be, charged, assessed or imposed upon the
                        Premises or upon the owner or occupier of them save
                        taxes arising from the receipt of rents or from dealings
                        with the Landlord's reversionary interest in the
                        Premises or the Building;

                (b)     Value Added Tax (or any tax of a similar nature that may
                        be substituted for it, or levied in addition to it)
                        chargeable in respect of any payment made by the Tenant
                        under any of the provisions of or in connection with
                        this Lease, or paid by the Landlord on any payment made
                        by the Landlord where the Tenant agrees in this Lease to
                        reimburse the Landlord for such payment.

        Electricity, Gas and Other Services Consumed

        5.3     To pay to the suppliers and to indemnify the Landlord against
                all charges for electricity, gas and other services consumed or
                used at or in relation to the Premises (including meter rents)
                where a separate supply is provided for the Premises.

        Repair

        5.4     To repair and keep in repair the Premises (damage caused by an
                inherent or latent structural defect in the Building or Insured
                Risk



                                      -8-
<PAGE>   10


                excepted other than to the extent that the insurance monies are
                irrecoverable in consequence of any act or default of the Tenant
                or anyone at the Premises expressly or by implication with the
                Tenant's authority) and to replace from time to time the
                Landlord's fixtures, fittings and appurtenances in the Premises
                which may be or become beyond repair at any time during or at
                the expiration of the Term.

        Alterations and Additions

        5.5.1   Not to:

                (a)     commit or permit waste, on or at the Premises;

                (b)     build, erect, construct or place any new or additional
                        building or structure on the Premises, including
                        (without prejudice to the generality of the foregoing)
                        any hut, shed, garage, cycle shelter, store, caravan,
                        house on wheels, or any temporary or moveable building
                        or structure;

                (c)     make any alterations, additions or improvements to the
                        Premises provided that:

                        (i)     internal non-structural alterations by the
                                Tenant in the Premises of a design and of
                                materials approved in writing by the Landlord
                                (such approval not to be unreasonably withheld
                                or delayed) shall not be deemed to be a breach
                                of this covenant; and

                        (ii)    the Tenant may with the consent of the Landlord
                                (such consent not to be unreasonably withheld or
                                delayed) install and alter internal partitions
                                from time to time and install new partitions.

        5.5.2   To remove any additional buildings, additions, alterations or
                improvements made to the Premises at the expiration of the Term
                if so requested by the Landlord and to make good any part or
                parts of the Premises which may be damaged by such removal.

        5.5.3   Not to cut injure or remove nor, except in accordance with
                clause 5.5.4, make any connection with the Pipes serving the
                Premises either exclusively or in conjunction with other
                premises.


                                      -9-

<PAGE>   11
5.5.4       To make connection with those Pipes that exclusively serve the
            Premises only in accordance with plans and specifications approved
            by the Landlord (such approval not to be unreasonably withheld or
            delayed).

Statutory Obligations

5.6.1       At the Tenant's own expense, to execute all works and provide and
            maintain all arrangements upon or in respect of the Premises or the
            use to which the Premises are being put that are required (whether
            by the lessor, the lessee or the occupier) in order to comply with
            the requirements of any statute (already or in the future to be
            passed) or any government department, local authority, other public
            or competent authority, or court of competent jurisdiction.

5.6.2       Not to do in or near the Premises any act or thing by reason of
            which the Landlord may under any enactment incur, have imposed upon
            it, or become liable to pay any penalty, damages, compensation,
            costs, charges or expenses.

5.6.3       Without prejudice to the generality of the foregoing, to comply in
            all respects with the provisions of any statutes and any other
            obligations imposed by law or by any byelaws applicable to the
            Premises or in regard to carrying on the trade or business for the
            time being carried on by the Tenant on the Premises.

Access of Landlord and Notice to Repair

5.7.1       To permit the Landlord:

            (a)   to enter upon the Premises for the purpose of ascertaining
                  that the covenants and conditions of this Lease have been
                  observed and performed;

            (b)   to view (and to open up floors and ceiling where the same is
                  reasonably required in order to view) the state of repair and
                  condition of the Premises; and

            (c)   to give to the Tenant (or leave upon the Premises) a notice
                  specifying any repairs, cleaning, maintenance and painting
                  that the Tenant has failed to execute in breach of the terms
                  hereof and to request the Tenant forthwith to execute the same
                  including the making good of the said opening-up (if any)



                                     - 10 -
<PAGE>   12
                  provided that any such opening-up shall be made good by and at
                  the cost of the Landlord where the same reveals no breaches of
                  the terms hereof which justified such opening up.

5.7.2       Forthwith to repair, cleanse, maintain and paint the Premises as
            required by such notice.

5.7.3       If within one month of the service of such a notice, the Tenant
            shall not have commenced and be proceeding diligently with the
            execution of the work referred to in the notice, or shall fail to
            complete the work within a reasonable time or if in the Landlord's
            Surveyor's reasonable opinion the Tenant is unlikely to have
            completed the work by the date upon which the work has to be
            completed to permit the Landlord to enter the Premises to execute
            such work as may be necessary to comply with the notice, and to pay
            to the Landlord the cost of so doing and all expenses incurred by
            the Landlord (including legal. costs and surveyor's fees) within
            fourteen days of a written demand.

Alienation

5.8.1       Not to hold on trust for another, part with or share the possession
            or occupation of the whole of the Premises except as permitted under
            clause 5.8.2 hereof.

5.8.2       Not to assign, underlet (save as permitted under clause 5.8.4
            hereof), charge, hold on trust for another, part with nor share
            possession or occupation of part only of the Premises save that the
            Tenant may share occupation of the Premises or part or parts thereof
            with other group companies of the Tenant as defined by Article 31 of
            the Business Tenancies (Northern Ireland) Order 1996.

5.8.3       Not to assign nor charge the whole of the Premises without the prior
            written consent of the Landlord, such consent not to be unreasonably
            withheld or delayed, provided that the proposed assignee is of good
            financial standing and proved to be such to the reasonable
            satisfaction of the Landlord

5.8.4       Not to underlet the whole or part of the Premises without the prior
            written consent of the Landlord (such consent not to be unreasonably
            withheld or delayed) provided that the proposed sub-tenant is of
            good financial standing and proved to be such to the reasonable
            satisfaction of the Landlord PROVIDED ALWAYS that each such
            underletting of part of the Premises must comprise the entire part
            of the third floor


                                      -11-
<PAGE>   13
            hereby demised which is located on either side of the lifts/main
            stairs/toilet area on the said floors.

5.8.5       Prior to any permitted assignment, to procure that the assignee
            enters into direct covenants with the Landlord to perform and
            observe all the Tenant's covenants and all other provisions during
            the residue of the Term.

5.8.6       Prior to any permitted underletting, to procure that the underlessee
            enters into direct covenants with the Landlord as follows:

            (a)   to observe and perform all the Tenant's covenants and all
                  other provisions of this Lease (other than the payment of
                  rents) during the residue of the Term;

            (b)   an unqualified covenant by the underlessee that the
                  underlessee will not assign, underlet, charge, hold on trust
                  for another, part with nor share the possession or occupation
                  of part only of the underlet premises or underlet, charge,
                  hold on trust for another, part with nor share the possession
                  or occupation of the whole of the underlet premises; and

            (c)   a covenant by the underlessee that the underlessee will not
                  assign the whole of the premises demised by the said
                  underlessee without obtaining the prior written consent (which
                  shall not be unreasonably withheld) of the Landlord under this
                  Lease.

5.8.7       That each and every permitted underlease shall be granted without
            any fine or premium, at a rent equal to the then open market rental
            value of the Premises or the proportionate part thereof where part
            of the Premises is underlet (such rental value to be assessed in
            accordance with the provisions of the Fourth Schedule of this Lease)
            or if greater the Rent then being paid or the proportionate part of
            the Rent then being paid where only part of the Premises is underlet
            such rent being payable in advance on the days on which Rent is
            payable under this Lease, and shall contain provisions approved by
            the Landlord:

            (a)   for the upwards only review of the rent thereby reserved on
                  the basis and on the dates on which the rent is to be reviewed
                  in this Lease;



                                      -12-
<PAGE>   14

            (b)   prohibiting the underlessee from doing or allowing any act or
                  thing in relation to the underlet premises inconsistent with
                  or in breach of the provisions of this Lease;

            (c)   a condition for re-entry by the underlessor on breach of any
                  covenant by the underlessee, and

            (d)   an absolute covenant against underletting and the same
                  restrictions on assignment charging holding on trust for
                  another parting with or sharing with another possession
                  occupation of the underlet premises and the same provisions
                  for direct covenants and registration as in this Lease.

5.8.8       To enforce the performance and observance by every such underlessee
            of the provisions of the underlease and not at any time either
            expressly or by implication to waive any breach of the covenants or
            conditions on the part of any underlessee or assignee of any
            underlease nor (without the consent of the Landlord such consent not
            to be unreasonably withheld) vary the terms or accept a surrender of
            any permitted underlease.

Nuisance etc and Residential Restrictions

5.9.1       Not to do (or permit or suffer to remain upon the Premises) anything
            which may be or become or cause a nuisance, injury or damage to the
            Landlord or its tenants or the occupiers of adjacent or neighboring
            premises.

5.9.2       Not to use the Premises for a sale by auction or for any dangerous,
            noxious, noisy or offensive trade or business, nor for any illegal
            or immoral act or purpose.

5.9.3       Not to sleep or allow any person to sleep on the Premises and not to
            use the Premises for residential purposes nor keep any animal, fish,
            reptile or bird on the Premises.

Landlord's Costs

5.10        To pay to the Landlord all reasonable costs, fees, charges,
            disbursements and expenses (including without prejudice to the
            generality of the foregoing those payable to Counsel, Solicitors,
            Surveyors and bailiffs) incurred by the Landlord in relation or
            incidental to:

                                      -13-


<PAGE>   15

            (a)   every application made by the Tenant for a consent or license
                  required or made necessary by the provisions of this Lease
                  whether the same be granted or refused or proffered subject to
                  any lawful qualification or condition or whether the
                  application be withdrawn;

            (b)   the preparation and service of notices under the 1996 Order;

            (c)   the recovery or attempted recovery of arrears of rent or other
                  sums due from the Tenant; and

            (d)   any steps taken in contemplation of or in connection with the
                  preparation and service of a Schedule of Dilapidations during
                  or after the expiration of the Term.

Planning Acts

5.11.1      To comply with the provisions and requirements of the Planning
            Acts, whether as to the Permitted User or otherwise, and to
            indemnify (both during or following the expiration of the Term) and
            keep the Landlord indemnified against all liability whatsoever
            including costs and expenses in respect of any contravention.

5.11.2      At the expense of the Tenant, to obtain all planning permissions
            and to serve all such notices as may be required for the carrying
            out of any operations or user on the Premises which may constitute
            Development, provided that no application for planning permission
            shall be made without the previous consent of the Landlord (such
            consent not to be unreasonably withheld or delayed).

5.11.3      Subject only to any statutory direction to the contrary, to pay and
            satisfy any charge or levy that may hereafter be imposed under the
            Planning Acts in respect of the carrying out or maintenance of any
            such operations, or the commencement or continuance of any such
            user.

5.11.4      Notwithstanding any consent which may be granted by the Landlord
            under this Lease, not to carry out or make any alteration or
            addition to the Premises, or any change of use until:

            (a)   all necessary notices under the Planning Acts have been served
                  and copies produced to the Landlord;


                                      -14-

<PAGE>   16

            (b)   all necessary permissions under the Planning Acts have been
                  obtained and produced to the Landlord; and

            (c)   the Landlord has acknowledged that every necessary planning
                  permission is acceptable to it (such acknowledgement not to be
                  unreasonably withheld or delayed);


            the Landlord being entitled to refuse to acknowledge its acceptance
            of a planning permission on the grounds that any condition contained
            in it, or anything omitted from it, or the period referred to in it,
            would in the reasonable opinion of the Surveyor) be (or be likely to
            be) prejudicial to the Landlord's interest in the Premises, the
            Building, or any Adjoining Property whether during or following the
            expiration of the Term.

5.11.5      Unless the Landlord shall otherwise direct, to carry out and
            complete before the expiration of the Term:

            (a)   any works stipulated to be carried out to the Premises by a
                  date subsequent to such expiration as a condition of any
                  planning permission granted for any Development begun before
                  the expiration of the Term; and

            (b)   any Development begun upon the Premises in respect of which
                  the Landlord shall or may be or become liable for any charge
                  or levy under the Planning Acts.

5.11.6      In any case where a planning permission is granted subject to
            conditions, and if the Landlord so requires, to provide security for
            the compliance with such conditions, and not to implement the
            planning permission until security has been provided.

5.11.7      If reasonably required by the Landlord, but at the cost of the
            Tenant, to appeal against any refusal of planning permission or the
            imposition of any conditions on a planning permission relating to
            the Premises following an application by the Tenant.

Plans Documents and Information

5.12.1      If called upon so to do, to produce to the Landlord or the Surveyor
            all plans, documents and other evidence as the Landlord may
            reasonably


                                      -15-
<PAGE>   17

            require in order to satisfy itself that the provisions of this Lease
            have been complied with.

5.12.2      If called upon so to do, to furnish to the Landlord, the Surveyor,
            any other surveyor acting for the Landlord, or any person acting as
            the Arbitrator under the Fourth Schedule, such information as may be
            reasonably requested in writing in relation to any pending or
            intended step under the 1996 Order or the implementation of the
            provisions of the Fourth Schedule.

Indemnities

5.13        To be responsible for, and to keep the Landlord fully indemnified
            against, all damage, damages, losses, costs, expenses, actions,
            demands, proceedings, claims and liabilities made against or
            suffered or incurred by the Landlord arising directly or indirectly
            out of:

            (a)   any act omission or negligence of the Tenant or its sub-
                  tenants or any persons at the Premises expressly or impliedly
                  with its or their Tenant's authority; or

            (b)   any breach or non observance by the Tenant or its sub-tenants
                  of the covenants, conditions or other provisions of this
                  Lease.

Re-letting Boards

5.14        To permit the Landlord at any time during the last six months of the
            Term to enter upon the Premises and affix and retain upon such part
            of the Premises as may be reasonable a notice for re-letting the
            same and during such period to permit persons with written
            authority of the Landlord or its agent at reasonable times of the
            day to view the Premises.

Rights of Light and Encroachments

5.15.1      Not to stop-up, darken or obstruct any windows or light belonging
            to the Building.

5.15.2      Not to permit any new window, light, opening, doorway, path
            passage, drain or other encroachment or easement to be made or
            acquired in against out of or upon the Premises and if any such


                                      -16-
<PAGE>   18
            window light opening path passage drain or other encroachment or
            easement shall be made or acquired, or attempted to be made or
            acquired, to give immediate notice to the Landlord and at the
            request and cost of the Landlord to adopt such means as may be
            reasonably required or deemed proper for preventing any such
            encroachment or the acquisition of any such easement.

Yield Up

5.16.1      At the expiration of the Term, to yield up the Premises in repair
            as required by this Lease and otherwise in accordance with the terms
            of this Lease, to give up all keys of the Premises to the Landlord,
            and to remove all lettering and signs erected by the Tenant in upon
            or near the Premises and forthwith to make good any damage caused by
            such removal.

5.16.2      If at the expiration of the Term, the Premises are not in the state
            of repair and decoration in which they should be having regard to
            the Tenant's covenants and conditions contained in this Lease, the
            Tenant shall (if so required by the Landlord) pay to the Landlord on
            demand by way of liquidated damages:

            (a)   such sum as shall be reasonably certified by the Surveyor to
                  represent in his professional opinion:

                  (i)   the cost of putting the Premises into the state of
                        repair and decoration in which they should have been had
                        the Tenant complied with the terms of this Lease; and

                  (ii)  the Rent at the rate prevailing at the expiration of the
                        Term that would have been payable under this Lease if
                        the Term had been extended for such period as is
                        necessary to put the Premises into the state of repair
                        and decoration in which they should have been; and

            (b)   the reasonable fees of the Surveyor for the preparation and
                  service of a schedule of dilapidations and the preparation and
                  issue of the said certificate.

Interest on Arrears

5.17.1      If the Tenant shall fail to pay the Rent within 14 days of the due
            date or Service Charge and/or Insurance Rent within 14 days of
            formal



                                      -17-
<PAGE>   19
            demand or any other sum due under this Lease within 14 days of
            formal demand the Tenant shall pay the Landlord Interest on the
            rents or other sum from the date when it was due to the date on
            which it is paid (and such Interest shall be deemed to be rent due
            to the Landlord).

5.17.2      Nothing in the preceding clause shall entitle the Tenant to
            withhold or delay any payment of the rents or any other sum due
            under this Lease after the date upon which it falls due, or in any
            way prejudice affect or derogate from the rights of the Landlord in
            relation to the said non-payment, including (but without prejudice
            to the generality of the foregoing) under the proviso for re-entry
            contained in this Lease.

Registration of Documents, Rent Reviews, Notices and Keys

5.18.1      Within twenty eight days of any assignment, charge, underlease or
            sub-underlease or any transmission or other devolution relating to
            the Premises, to produce for registration with the Landlord's
            Solicitor the said deed or document (or a certified copy thereof)
            and to pay the Landlord's Solicitor's charges for the registration
            of every such document.

5.18.2      Where there has been an underletting of all or part of the
            Premises, to give notice of the details of the determination of
            every rent review to the Landlord within 28 days of the
            determination.

5.18.3      To give full particulars to the Landlord of any notice direction
            order or proposal for the same made given or issued to the Tenant by
            any local or public authority within seven days of receipt, and if
            so required by the Landlord to produce it to the Landlord and (where
            such notice direction order or proposal relates to the Tenant's
            obligations under this Lease) without delay to take all necessary
            steps to comply with the notice direction or order, and at the
            request of the Landlord and at the equal joint cost of the Landlord
            and of the Tenant to make or join with the Landlord in making such
            objection or representation against or in respect of any proposal
            for a notice direction or order as the Landlord shall deem
            expedient.

5.18.4      To ensure that at all times the Landlord has written notice of the
            name, home address and home telephone number of at least one
            keyholder of the Premises.

                                      -18-

<PAGE>   20
Sale of Reversion etc

5.19        To permit upon reasonable notice at any time during the Term
            prospective purchasers of or dealers in or agents instructed in
            connection with the sale of the Landlord's reversion or of any
            interest superior to the Term to view the Premises without
            interruption providing the same are authorised in writing by the
            Landlord or its agents.

Defective Premises

5.20        To give notice to the Landlord of any defect in the Premises which
            might give rise to an obligation on the Landlord to do or refrain
            from doing any act or thing in order to comply with the provisions
            of this Lease or the duty of care imposed on the Landlord pursuant
            to the Defective Premises (NI) Order 1975 or otherwise, and at all
            times to display and maintain all notices which the Landlord may
            from time to time reasonably require to be displayed at the
            Premises.

New Guarantor

5.21        Within fourteen days of the death during the Term of any Guarantor
            or of such person becoming bankrupt or having a Receiving Order made
            against him or being a Company passing a Resolution to wind up, or
            entering into liquidation or having a receiver appointed, to give
            notice of this to the Landlord and if so required by the Landlord at
            the expense of the Tenant within twenty eight days to procure some
            other person acceptable to the Landlord (such acceptance not to be
            unreasonably withheld) to execute a guarantee in respect of the
            Tenant's obligations contained in this Lease in the form set out in
            clause 9.

Landlord's Rights

5.22        To permit the Landlord at all times during the Term to exercise
            without interruption or interference any of the rights granted to it
            by virtue of the provisions of this Lease.

Office Covenants

5.23        To observe and perform the Office Covenants.


                                      -19-


<PAGE>   21
Criminal Damage

5.24        If the Premises or any part thereof should be damaged or destroyed
            by an event for which compensation is payable under the provisions
            of the Criminal Damage (Compensation) (Northern Ireland) Order 1977
            to immediately give notice thereof to the Landlord and forthwith to
            institute a claim under the said Order and to pursue such claim
            expeditiously AND EITHER to apply all compensation paid relating to
            the Premises in rebuilding and reinstating the same pursuant to the
            Tenant's covenants herein contained making good any deficiency out
            of the Tenant's own monies OR if the Landlord so reasonably requires
            to assign its rights under any such claim and all monies payable
            thereunder and to pay to the Landlord any deficiency and if the
            amount of compensation awarded should be reduced or excluded as the
            result of the general conduct or act or neglect of the Tenant or its
            sub-tenants (if any) or anyone at or near the Premises expressly or
            by implication with its or their authority the Tenant shall pay to
            the Landlord any amount by which any compensation recoverable by the
            Landlord shall be reduced by reason of such conduct, act or neglect.

Stamp Duty and other expenses

5.25        To pay the Stamp Duty payable on this Lease and a counterpart
            thereof, the cost of registering this Lease in the Registry of Deeds
            (if applicable).

6.    LANDLORD'S COVENANTS

The Landlord COVENANTS with the Tenant:

6.1         To permit the Tenant to peaceably and quietly hold and enjoy the
            Premises without any lawful interruption or disturbance from or by
            the Landlord or any person claiming under or in trust for the
            Landlord.


6.2         So long as Pivotal Corporation (NI) Limited or any Group Company of
            Pivotal Corporation (NI) Limited is the Tenant to give to the Tenant
            immediate notice of receipt by the Landlord from the then tenant of
            the 1st and 2nd floors of the Building written notice of such
            tenant's intention to exercise any option to terminate its Lease of
            the said 1st and 2nd floors.

6.3         Subject to the Tenant paying any relevant costs under clause 7.9 to
            ensure that the Tenant may use the Premises and have access thereto
            at all times


                                      -20-
<PAGE>   22
so far as same lies within the Landlord's control such access to include access
through the main entrance from Upper Queen Street.

7.      SERVICES

        7.1     The Landlord covenants with the Tenant to perform the Services
                throughout the Term provided that the Landlord shall not be
                liable to the Tenant in respect of:

                (a)     any failure or interruption in any of the Services by
                        reason of necessary repair, replacement, maintenance of
                        any installations or apparatus, or their damage or
                        destruction, or by reason of mechanical or other defect
                        or breakdown, or frost or other inclement conditions, or
                        shortage of fuel, materials, water or labour, or any
                        other cause beyond the Landlord's control; and

                (b)     any act, omission, or negligence of any porter,
                        attendant or other person undertaking the Services or
                        any of them on behalf of the Landlord.

        7.2     For the purposes of this clause:

                (a)     'Computing Date' means the 31st January in every year
                        of the Term or such other date as the Landlord may from
                        time to time nominate; and

                (b)     'Financial Year' means the period;

                        (i)     from the commencement of the term to (and
                                including) the first Computing Date and
                                thereafter;

                        (ii)    between two consecutive Computing Dates
                                (excluding the first but including the second
                                Computing Date in the period).

                (c)     'Due Proportion' means the due proportion (subject to
                        clause 7.7) of the Annual Expenditure payable by the
                        Tenant equivalent to the same proportion pro rata as the
                        Total Lettable Area of the Premises bears to the total
                        lettable area of the Building (excluding any ground
                        floor premises) provided that in calculating the Due
                        Proportion the Tenant shall not be



                                      -21-
<PAGE>   23

                        responsible to contribute towards costs incurred as a
                        result of inherent or latent structural defects in the
                        Building.

        7.3     The Landlord or its surveyor or other nominated agent shall as
                soon as convenient after each Computing Date prepare an account
                showing the Annual Expenditure for that Financial Year, and
                containing a fair summary of the expenditure referred to
                therein, and same shall (in the absence of manifest error) be
                conclusive evidence for the purposes of this Lease of all
                matters of fact referred to in the said account.

        7.4     The Tenant shall pay for the period from the commencement date
                of the Term to the next Computing Date an initial provisional
                Service Charge in respect of the Due Proportion (calculated upon
                an estimate by the Surveyor acting as an expert and not as an
                arbitrator of what the Annual Expenditure is likely to be for
                the current Financial Year), the first payment being a
                proportionate sum in respect of the period from and including
                the commencement date of the Term to and including the day
                before the next quarter day to be paid on the date hereof, the
                subsequent payments to be made in advance on the usual quarter
                days in respect of the said quarters.

        7.5     The Tenant shall pay for the next and each subsequent Financial
                Year a provisional sum in respect of the Due Proportion
                (calculated upon an estimate by the Surveyor acting as an expert
                and not as an arbitrator of the Annual Expenditure is likely to
                be for that Financial Year) by four equal quarterly payments on
                the usual quarter days.

        7.6     If the Service Charge for any Financial Year shall:

                (a)     exceed the provisional sum for that Financial Year the
                        excess shall be due to the Landlord on demand; or

                (b)     be less than the said provisional sum the overpayment
                        shall be credited to the Tenant against the next
                        quarterly payment of the Rent and Service Charge.

        7.7     If at any time during the Term the total property enjoying or
                capable of enjoying the benefit of any of the Services be
                increased or decreased on a permanent basis, or the benefit of
                any of the Services be extended on like basis to any adjoining
                or neighbouring property, the Due Proportion shall be varied
                with effect from the Computing Date following such event by
                agreement between the parties, or in default of agreement within
                three months of the first proposal for variation



                                      -22-
<PAGE>   24

                made by either party as shall be determined to be a fair and
                reasonable variation reflecting the event in question by the
                Surveyor (acting as an expert and not as an arbitrator) except
                that nothing herein contained shall imply an obligation on the
                part of the Landlord to provide the Services to any adjoining or
                neighbouring property.

        7.8     The Landlord may withhold, add to, extend, vary or make any
                alteration in the rendering of the Services, or any of them,
                from time to time if the Landlord at its discretion deems it
                desirable to do so the Landlord acting at all times in the
                interests of good estates management.

        7.9     In the event that following a request by the Tenant and
                agreement to such request by the Landlord (such request not to
                be unreasonably refused provided that the Landlord shall not
                refuse the Tenant's request for Services outside the Permitted
                Hours which are reasonably required for the use of the Premises
                outside the Permitted Hours including (without prejudice to the
                generality of the foregoing) lifts) (and as the case may be
                following any request by and agreement with any other tenant(s)
                in the Building (excluding any ground floor premises)) the
                Landlord provides any Services or incurs any Additional Items of
                Expenditure outside the Permitted Hours then the Tenant shall be
                responsible and liable to pay for all extra Costs (including any
                VAT payable thereon) to the Annual Expenditure as a result of
                the use of the Premises outside the Permitted Hours or a
                reasonable proportion (to be decided by the Surveyor acting as
                an expert and not as an arbitrator) of such extra Costs where
                any other tenant(s) in the Building (excluding any ground floor
                premises) also use their premises outside the Permitted Hours.

8.      INSURANCE

        8.1     The Tenant warrants that prior to the execution of this Lease it
                has disclosed to the Landlord in writing any conviction,
                judgment, or finding of any court or tribunal relating to the
                Tenant (or any director, other officer, or major shareholder of
                the Tenant) of such a nature as to be likely to affect the
                decision of any insurer or underwriter to grant or to continue
                insurance of any of the risks appearing in this clause.

        8.2     Subject to the Tenant paying the Insurance Rent, the Landlord
                covenants to insure the Building subject to such excesses
                exclusions or limitations as the Landlord's insurers may
                require;



                                      -23-
<PAGE>   25

                in such insurance office or with such underwriters and through
                such agency and for such amount as in the reasonable opinion of
                the Landlord from time to time represents the full cost of
                rebuilding or reinstatement including architects', surveyors'
                and other professional fees, the cost of debris removal,
                demolition, site clearance, any works that may be required by
                statute and incidental expenses.

        8.3     Such insurance shall be against:

                (a)     loss or damage by fire, accidental explosion, storm,
                        lightning, subsidence, tempest, flood, burst pipes and
                        tanks, impact and (in peacetime) aircraft and articles
                        dropped therefrom, and such other risks insurance
                        against which the Landlord may from time to time
                        reasonably deem necessary;

                (b)     the liability of the Landlord arising out of or in
                        connection with any matter involving or relating to the
                        Building;

                (c)     the loss of Rent and Service Charge payable under this
                        Lease from time to time (having regard to any review of
                        rent which may become due under this Lease) for three
                        years or such longer period as the Landlord may from
                        time to time reasonably consider to be sufficient for
                        the purposes of planning and carrying out rebuilding or
                        reinstatement; and

                (d)     (if available) any reduction in the amount of
                        compensation payable to the Landlord with respect to
                        repair or reinstatement of the Building following any
                        successful claim under the Criminal Damage
                        (Compensation) (Northern Ireland) Order 1977 due to
                        betterment.

        8.4     The Tenant shall pay the Insurance Rent on the date hereof for
                the period from and including the commencement date of the Term
                to the day before the next policy renewal date and thereafter
                the Tenant shall pay the Insurance Rent on demand and (if
                demanded) in advance of the policy renewal date.

        8.5     If and whenever during the Term:

                (a)     the Premises or any part of them or access to them are
                        destroyed or damaged by an Insured Risk so that the
                        Premises or any part of them are unfit for occupation or
                        use; and



                                      -24-
<PAGE>   26

                (b)     except to the extent that the insurance of the Premises
                        has been vitiated by the act, neglect, default or
                        omission of the Tenant or its sub-tenants or anyone at
                        the Premises expressly or by implication with its or
                        their authority;

                the Rent and the Service Charge or a fair proportion of the Rent
                and the Service Charge according to the nature and the extent of
                the damage sustained (the amount of such proportion to be
                reasonably determined by the Surveyor) shall be suspended and
                cease to be payable until the Premises, the damaged part, or the
                access shall have been reinstated so that the Premises or the
                damaged part are made fit for occupation or use or until the
                expiration of three years from the destruction or damage
                whichever is the shorter.

        8.6     If and whenever during the Term:

                (a)     the Premises and/or the Building are damaged or
                        destroyed by an Insured Risk; and

                (b)     except to the extent that the payment of the insurance
                        monies is refused by reason of any act or default of the
                        Tenant or anyone at or near the Premises expressly or by
                        implication with the Tenant's authority;

                the Landlord will subject to clause 8.7 with all convenient
                speed take such steps as may be requisite and proper to obtain
                any planning permissions or other permits and consents that may
                be required under the Planning Acts or other Statute for the
                time being in force to enable the Landlord to rebuild and
                reinstate the Premises and/or the Building, and will as soon as
                these have been obtained spend and lay out all monies received
                in respect of such insurance (except sums in respect of loss of
                rent) in rebuilding or reinstating the Premises and/or the
                Building so destroyed or damaged making good any deficiency in
                such insurance monies out of the Landlord's own monies (save to
                the extent that such deficiency arises from the act neglect or
                default of the Tenant or its sub-tenants (if any) or anyone at
                or near the Premises with its or their authority) provided that
                the Landlord shall not be liable to rebuild or reinstate the
                Premises if the Landlord is unable (having used all reasonable
                endeavours) to obtain all planning permissions, permits and
                consents necessary to execute such rebuilding and reinstating,
                or if this Lease shall be frustrated (or if the rebuilding or
                reinstating is prevented for any other reason beyond the



                                      -25-
<PAGE>   27

                control of the Landlord) in which event the Landlord shall be
                entitled to retain all the insurance monies received by the
                Landlord.

        8.7     If after three years from the date of damage or destruction of
                the Premises and/or the Building by an Insured Risk or by any
                event giving rise to a claim under the Criminal Damage
                (Compensation) (Northern Ireland) Order 1977 the Premises and/or
                the Building remain completely unfit for occupation and use, the
                Landlord or the Tenant may by not less than three month's notice
                given to expire at any time prior to the Premises and/or the
                Building being reinstated or repaired and made fit for
                occupation and use determine this Lease ('the Determination
                Notice') and upon the expiry of the Determination Notice this
                Lease shall determine without prejudice to any rights or
                remedies which may then have accrued to either party against the
                other in respect of any breach of any of the covenants and
                conditions contained in this Lease and the Landlord shall be
                entitled to retain the insurance moneys received by the
                Landlord.

        8.8     The Tenant COVENANTS with the Landlord:

                        (a)     to comply with all the reasonable and/or normal
                                requirements and recommendations of the
                                insurers;

                        (b)     not to do or omit anything that could cause any
                                policy of insurance on the Premises to become
                                void or voidable wholly or in part nor (unless
                                the Tenant shall have previously notified the
                                Landlord and have agreed to pay the increased
                                premium) anything whereby additional insurance
                                premiums may become payable;

                        (c)     to keep the Premises supplied with such fire
                                fighting equipment as the insurers and the fire
                                authority may require and to maintain the same
                                to their satisfaction;

                        (d)     not to store or bring onto the Premises any
                                article, substance or liquid of a specially
                                combustible, inflammable or explosive nature and
                                to comply with the requirements and
                                recommendations of the fire authority (and the
                                reasonable requirements of the Landlord) as to
                                fire precautions relating to the Premises;

                        (e)     not to obstruct the access to any fire equipment
                                or the means of escape from the Premises;



                                      -26-
<PAGE>   28

                (f)     to give notice to the Landlord forthwith upon the
                        happening of any event which might affect any insurance
                        policy relating to the Premises;

                (g)     if and whenever during the Term the Premises or any part
                        thereof are damaged or destroyed by an Insured Risk, and
                        the insurance money under the policy of insurance is by
                        reason of any act or default of the Tenant or its
                        sub-tenants or anyone at the Premises expressly or by
                        implication with its or their Tenant's authority wholly
                        or partially irrecoverable, forthwith in every such case
                        to pay to the Landlord on demand with Interest the
                        amount of such insurance money so irrecoverable in which
                        event the provisions of clauses 8.5 and 8.6 shall apply;

                (h)     forthwith to inform the Landlord in writing of any
                        conviction judgment or finding of any court or tribunal
                        relating to the Tenant (or any director other officer or
                        major shareholder of the Tenant) of such a nature as to
                        be likely to affect the decision of any insurer or
                        underwriter to grant or to continue insurance of any of
                        the above mentioned risks; and

                (i)     if at any time the Tenant shall be entitled to the
                        benefit of any insurance on the Premises (which is not
                        affected or maintained in pursuance of any obligation
                        herein contained), to apply all monies received by
                        virtue of such insurance in making good the loss or
                        damage in respect of which the same shall have been
                        received.

        8.9     If at any time during the Term the total property of which the
                Premises are a part shall be increased or decreased on a
                permanent basis the percentage referred to in clause 1.13 shall
                be varied in the manner set out in clause 7.7.

9.      The Guarantor COVENANTS with the Landlord:

        9.1     If at any time during the Term the Tenant shall make any default
                in payment of the rents or in observing or performing any of the
                material covenants, conditions or other terms of this Lease the
                Guarantor will pay the rents and observe or perform the
                covenants, conditions or terms in respect of which the Tenant
                shall be in default notwithstanding:



                                      -27-
<PAGE>   29

                (a)     any time or indulgence granted by the Landlord to the
                        Tenant, or any neglect or forbearance of the Landlord in
                        enforcing the payment of rent or the observance or
                        performance of the Tenant's covenants, or any refusal by
                        the Landlord to accept rent tendered by or on behalf of
                        the Tenant at a time when the Landlord was entitled to
                        re-enter the Premises;

                (b)     that the terms of this Lease may have been varied by
                        agreement between the parties;

                (c)     that the Tenant shall have surrendered part of the
                        Premises, in which event the liability of the Guarantor
                        hereunder shall continue in respect of the part of the
                        Premises;

                (d)     any other act or thing whereby but for this provision
                        the Guarantor would have been released.

        9.2     If at any time during the Term the Tenant (being an individual)
                shall become bankrupt or (being a company) shall enter into
                liquidation and the trustee-in-bankruptcy or liquidator shall
                disclaim this Lease, the Guarantor will if the Landlord shall by
                notice within sixty (60) days after such disclaimer so require
                take from the Landlord a lease of the Premises for the residue
                of the Term which would have remained had there been no
                disclaimer at the Rent then being paid hereunder and subject to
                the same covenants and conditions as in the Lease with the
                exception of this clause, such new lease to take effect from the
                date of the said disclaimer and in such case the Guarantor shall
                pay the costs of such new lease and execute and deliver to the
                Landlord a counterpart thereof.

10.     PROVISOES

        Re-entry

        10.1    If at any time during the Term:

                (a)     the rents (or any of them or any part thereof) shall be
                        in arrear and unpaid for 14 days after becoming payable
                        (whether formally demanded or not) or shall be unpaid
                        within 14 days of demand in the case of Service Charge
                        and Insurance Rent; or



                                      -28-
<PAGE>   30

                (b)     there shall be any breach, non-performance or
                        non-observance by the Tenant of any of the covenants and
                        conditions contained in this Lease; or

                (c)     the Tenant (being an individual) becomes bankrupt or
                        (being a company) enters into liquidation whether
                        compulsory or voluntary (save for the purpose of
                        amalgamation or reconstruction of a solvent company) or
                        has a receiver appointed of its undertaking or (in
                        either case) enters into an arrangement or composition
                        for the benefit of its creditors or suffers any distress
                        or execution to be levied on its goods;

                the Landlord may at any time thereafter (and notwithstanding the
                waiver of any previous right of re-entry) re-enter the Premises
                or any part thereof in the name of the whole and thereupon the
                Term shall absolutely cease and determine but without prejudice
                to any rights or remedies which may then have accrued to the
                Landlord against the Tenant in respect of any antecedent breach
                (including the breach in relation to which re-entry is made) of
                any of the covenants and conditions contained in this Lease.

        Covenants Relating to Adjoining Land

        10.2    Nothing contained in or implied by this Lease shall give the
                Tenant the benefit of or the right to enforce or to prevent the
                release or modification of any covenant agreement or condition
                entered into by any tenant of the Landlord in respect of any
                property not comprised in this Lease.

        Disputes with Adjoining Occupiers

        10.3    If any dispute arises between the Tenant and the lessees tenants
                or occupiers of adjoining or neighbouring property belonging to
                the Landlord as to any easement, right or privilege in
                connection with the use of the Premises and the adjoining
                property, or as to the amount of any contribution towards the
                expenses or services used in common with any other property it
                shall be decided by the Landlord or in such manner as the
                Landlord shall direct.

        Floor Area

        10.4    Save in the case of manifest error, the figure set out in clause
                1.4 shall for all purposes in relation to this Lease be taken as
                representing the



                                      -29-
<PAGE>   31

                Total Lettable Area of the Premises unless and until any
                alteration shall be carried out to the Premises with the
                Landlord's consent the effect of which is to increase or
                decrease the said area.

        Effect of Waiver

        10.5    Each of the Tenant's covenants shall remain in full force both
                at law and in equity notwithstanding that the Landlord shall
                have waived or released temporarily any such covenant, or waived
                or released temporarily or permanently revocably or irrevocably
                a similar covenant or similar covenants affecting other
                adjoining or neighbouring premises belonging to the Landlord.

        Rights Easements etc

        10.6    The operation of Section 6 of the Conveyancing and Law of
                Property Act 1881 shall be excluded from this Lease and the only
                rights granted to the Tenant are those expressly set out in this
                Lease and the Tenant shall not by virtue of this Lease be deemed
                to have acquired, or be entitled to, and the Tenant shall not
                during the Term acquire or become entitled by any means
                whatsoever to, any right or easement from or over or affecting
                any other land or premises now or at any time hereafter
                belonging to the Landlord and not comprised in this Lease.

        Party Walls

        10.7    The internal division walls that divide the Premises from the
                adjoining units in the Building shall be deemed to be party
                walls and shall be maintained at the equally shared expense of
                the Tenant and the other respective estate owners.

        Exclusion of Use Warranty

        10.8    Nothing in this Lease or in any consent granted by the Landlord
                under this Lease shall imply or warrant that the Premises may be
                used for the purpose herein authorised (or any purpose
                subsequently authorised) under the Planning Acts.

        Accidents

        10.9    The Landlord shall not be responsible to the Tenant or its
                sub-tenants or to anyone at the Premises expressly or by
                implication with its or



                                      -30-

<PAGE>   32
                their authority for any accident happening or injury suffered or
                for any damage to or loss of any chattel sustained in the
                Premises or the Building save and to the extent of the
                Landlord's insurance cover therefor.

        Entire Understanding

        10.10   This Lease embodies the entire understanding of the parties
                relating to the Premises or to any of the matters dealt with by
                any of the provisions of this Lease save for pre-lease
                enquiries.

        Representations

        10.11   The Tenant acknowledges that this Lease has not been entered
                into in reliance wholly or partly on any statement or
                representation made by or on behalf of the Landlord except any
                such statement or representation that is expressly set out in
                this Lease save for pre-lease enquiries.

        Licences etc Under Hand

        10.12   Whilst the Landlord is a limited company or other corporation,
                all licences, consents, approvals and notices required or
                permitted to be given by the Landlord shall be sufficiently
                given if given under the hand of a Director, the Secretary or
                other duly authorised officer of the Landlord (or the Surveyor
                on behalf of the Landlord).

        Tenant's Property

        10.13   If after the Tenant has vacated the Premises on the expiry of
                the Term any property of the Tenant remains in or on the
                Premises, and the Tenant fails to remove it within seven days
                after being requested in writing by the Landlord so to do, or if
                after using reasonable endeavours the Landlord is unable to make
                such a request to the Tenant within fourteen days from the first
                attempt so made by the Landlord:

                (a)     the Landlord may as the agent of the Tenant sell such
                        property, 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 belonged to the Tenant;



                                      -31-
<PAGE>   33

                (b)     if the Landlord having made reasonable efforts is unable
                        to locate the Tenant the Landlord shall be entitled to
                        retain the said proceeds of sale absolutely unless the
                        Tenant shall claim the same within six months of the
                        date upon which the Tenant vacated the Premises; and

                (c)     the Tenant shall indemnify the Landlord against any
                        damage occasioned to the Premises or the Building or any
                        adjacent or neighbouring premises of the Landlord and
                        any actions, claims, proceedings, costs, expenses and
                        demands made against the Landlord caused by or related
                        to the presence of the property in or on the Premises.

        Service of Notices

        10.14   The provisions of Section 67 of the Conveyancing and Law of
                Property Act 1881 as amended by the Recorded Delivery Service
                Act (Northern Ireland) 1963 shall apply to the giving and
                service of all notices and documents under or in connection with
                this Lease except that Section 67 shall be deemed to be amended
                as follows:

                In Section 67(4) the words "and that service shall be deemed to
                be made at the time at which the registered letter would in the
                ordinary course be delivered" shall be deleted and there shall
                be substituted the words "and that service shall be deemed to be
                made on the third Working Day after the registered letter has
                been posted, "Working Day" meaning any day from Monday to Friday
                (inclusive) other than Christmas Day, Good Friday and any
                statutory bank holiday".

        Tenant's Option to Determine

        10.15   Subject to the Tenant having paid the rents and all other sums
                due to the Landlord under this Lease as at the seventh
                anniversary of the commencement date of the Term the Tenant
                shall have the option to determine this Lease on the seventh
                anniversary of the commencement date of the Term on giving
                either at least twelve months prior written notice to the
                Landlord or at least six months prior written notice to the
                Landlord (time to be of the essence) and on the said seventh
                anniversary of the commencement date of the Term this Lease
                shall absolutely cease and determine without prejudice to any
                rights or remedies which may then have accrued to either party
                against the other in respect of any breach of covenant or other
                term of this Lease



                                      -32-
<PAGE>   34

                PROVIDED THAT in the event that the Tenant gives to the Landlord
                at least six months prior written notice but less than twelve
                months prior written notice the Tenant shall on the seventh
                anniversary of the commencement date of the Term pay to the
                Landlord a sum equal to 6 months Rent then payable together with
                Value Added Tax thereon.

        THE PARTIES HERETO HEREBY CERTIFY that there is no Agreement for Lease
        to which this Lease gives effect.

        IN WITNESS whereof this Lease has been executed by the parties hereto
        the day and year first herein written.



                                      -33-
<PAGE>   35

                                 FIRST SCHEDULE

                                  The Premises

`the Premises' mean all that part of the Building referred to in clause 1.3 for
the purposes of identification only shown edged red on the Plan including:

(a)     the paint, paper and other decorative finishes applied to the interior
        of the exterior walls of the Building but not any other part of the
        exterior walls;

(b)     the floor finishes so that the lower limit of the Premises includes such
        finishes but does not extend to anything below them;

(c)     the ceiling finishes so that the upper limit of the Premises shall
        include such finishes but shall not extend to anything above them;

(d)     the entirety of any non loadbearing internal walls within the Premises;

(e)     the inner half severed medially of the internal non loadbearing walls
        dividing the Premises from other parts of the Building;

(f)     all additions and improvements to the Premises;

(g)     all the Landlord's fixtures and fittings and fixtures of every kind
        which shall from time to time be in or upon the Premises whether
        originally affixed or fastened to or upon the same or otherwise except
        any such fixture installed by the Tenant and that can be removed from
        the Premises without defacing the same; and

(h)     any Pipes that exclusively serve the Premises.



                                       34
<PAGE>   36

                                SECOND SCHEDULE

                                 Rights Granted

1.      Common Parts

        The right for the Tenant and all persons expressly or by implication
        authorised by it (in common with the Landlord and all other persons
        having a like right) to use the Common Parts for all proper purposes in
        connection with the use and enjoyment of the Premises.

2.      Toilets

        The right for the Tenant as aforesaid (in common with the Landlord and
        all other persons having a like right) to use such toilets in the
        Building as shall be reasonably designated from time to time by the
        Landlord.

3.      Pipes

        The free passage and running (subject to temporary interruption for
        repair alteration or replacement) of water, soil, gas, electricity and
        other supplies to and from the Premises in and through the Pipes that
        now or hereafter serve the Premises presently or hereafter laid in on
        through or under other parts of the Building, and (if any) the Adjoining
        Property.

4.      Support

        The right of support and protection for the benefit of the Premises as
        is now enjoyed from all other parts of the Building.

5.      Car Park Spaces

        The right to use two car park spaces as designated from time to time by
        the Landlord or the Surveyor in the car park of the Building.

6.      Rear Gantry

        The right to place air conditioning and other equipment on the gantry
        area shown edged green on the map annexed hereto (the specifications and
        positioning of such equipment requiring the prior written approval of
        the Landlord such approval not to be unreasonably withheld or delayed).



                                       35
<PAGE>   37

                                 THIRD SCHEDULE

                                Rights Reserved

1.      Pipes

        The free and uninterrupted passage and running of water, soil, gas,
        electricity, telephone and other services or supply from and to other
        parts of the Building or any Adjoining Property in and through the Pipes
        which now are or may hereafter during the Term be in upon through under
        or over the Premises.

2.      Construct Easements

        The right to construct and to maintain in upon through under or over the
        Premises at any time during the Term any easements or services for the
        benefit of any part of the Building or any Adjoining Property.

3.1     Access

        The right at any time during the Term (at reasonable times and upon
        reasonable notice except in cases of emergency) to enter (or in cases of
        emergency to break and enter) the Premises to:

        (a)     inspect, cleanse, connect, lay, repair, remove, relay, replace
                with others alter or execute any works whatever to or in
                connection with, the Pipes, easements or services referred to in
                paragraphs 1 and 2 of this Schedule;

        (b)     view the state and condition of and repair and maintain the
                Building (and if any the Other Buildings) where such viewing or
                work would not otherwise be reasonably practicable;

        (c)     carry out work or do anything whatsoever comprised within the
                Landlord's obligations in this Lease whether or not the Tenant
                is liable to make a contribution;

        (d)     take schedules or inventories of fixtures and other items to be
                yielded-up on the expiry of the Term; and

        (e)     exercise any of the rights granted to the Landlord by this
                Lease.



                                       36
<PAGE>   38

3.2     The right with the Surveyor or any other surveyor acting for Landlord
        and any person acting as the Arbitrator under the Fourth Schedule at
        convenient hours and on reasonable prior notice to enter and to inspect
        and measure the Premises for all purposes connected with any pending or
        intended step under the 1996 Order or the implementation of the
        provisions of the Fourth Schedule.

4.      Scaffolding

        The right to erect scaffolding for the purpose of altering repairing
        maintaining or cleaning the Building (and (if any) the Other Buildings)
        and any buildings now or hereafter during the Term on the Adjoining
        Property notwithstanding that such scaffolding may temporarily restrict
        the access to or enjoyment and use of the Premises.

5.      Support etc

        The rights of light, air, support, shelter and all other easements and
        rights now or hereafter belonging to or enjoyed by other parts of the
        Building.

6.      Light

        Full right and liberty at any time hereafter:

        (a)     to alter raise the height of or re-build the Building or any
                part thereof or any of the Other Buildings;

        (b)     to erect the Other Buildings of any height; or

        (c)     to erect install or alter any structure erections fixtures
                fittings or equipment in on or to the Building or any part
                thereof or any of the other Buildings;

        in such manner as the Landlord shall think fit notwithstanding the fact
        that the same may obstruct, affect or interfere with the amenity of or
        access to the Premises, or the passage of light and air to the Premises
        Provided Always that there is provided at all times (save for any
        necessary temporary introduction thereto) adequate means of access to
        the Premises.



                                       37
<PAGE>   39

                                 FOURTH SCHEDULE

                                   Rent Review

1.1     The terms defined in this paragraph shall for all purposes of this
        Schedule have the meanings specified.

1.2     `Review Period' means the period between the Review Date and the expiry
        of the Term.

1.3     `the Assumptions' mean the following assumptions at the relevant Review
        Date:

        (a)     that the Premises are fit for and fitted out and equipped for
                immediate occupation and use (but disregarding the fit-out works
                themselves), and that no work has been carried out on the
                Premises by the Tenant its sub-tenants or their predecessors in
                title during the Term which has diminished the rental value of
                the Premises, and if the Premises have been destroyed or damaged
                they have been fully restored;

        (b)     that the Premises are available to let by a willing landlord to
                a willing tenant as a whole, without a premium, but with vacant
                possession, and subject to the provisions of this Lease (other
                than the amount of the Rent but including the provisions for
                rent review), for a term equal to the Term, and that the said
                letting would be renewed at the expiry of the term thereof under
                the provisions of the 1996 Order;

        (c)     that the covenants contained in this Lease on the part of the
                Landlord and the Tenant have been fully performed and observed;

        (d)     that the Tenant and tenants in the market generally are
                registered for Value Added Tax ("VAT") and will be able to set
                off in full by way of input tax any VAT payable in respect of
                any payment of rents against the output tax payable by them; and

        (e)     in case the Premises or the access thereto or any other part of
                the Building have been destroyed or damaged that they have been
                fully reinstated.



                                       38
<PAGE>   40

1.4     'the Disregarded Matters' mean:

        (a)     any effect on rent arising from the fact that the Tenant, its
                sub-tenants or their respective predecessors in title have been
                in occupation of the Premises;

        (b)     any goodwill attached to the Premises by reason of the carrying
                on at the Premises of the business of the Tenant its
                sub-tenants, or their predecessors in title in their respective
                businesses;

        (c)     any increase in rental value of the Premises attributable to the
                existence at the Review Date of any improvement to the Premises
                and carried out with consent where required otherwise than in
                pursuance of an obligation to the Landlord or its predecessors
                in title either:

                (i)     by the Tenant, its sub-tenants, or their respective
                        predecessors in title during the Term, or during any
                        period of occupation prior thereto arising out of an
                        agreement to grant such term; or

                (ii)    by any tenant or sub-tenant of the Premises before the
                        commencement of the Term, so long as the Landlord or its
                        predecessors in title have not since the improvement was
                        carried out had vacant possession of the relevant part
                        of the Premises.

        (d)     any obligation on the part of the Tenant to reinstate the
                Premises at the end or sooner determination of the Term or at
                any other time in pursuance of any obligation to the Landlord
                whether under this Lease or any other deed or document executed
                after the date of this Lease.

        (e)     any discount or rebate of the market rent to allow for any
                customary concessionary rent, rent free period or other
                inducement which a willing landlord would customarily grant to a
                willing tenant upon such a letting for tenant's fit-out works.

        (f)     all fit-out works carried out by occupiers of the Premises.

1.5     'the Arbitrator' means a person appointed by agreement between the
        parties, or in default of agreement within fourteen days of one party
        giving notice to the other of its nomination or nominations nominated by
        the Chairman on the



                                       39
<PAGE>   41

        application either party made not earlier than six months before the
        relevant Review Date or at any time thereafter.

1.6     'the Chairman' means the Chairman for the time being of the Northern
        Ireland branch of the Royal Institution of Chartered Surveyors, the duly
        appointed deputy of the Chairman, or any person authorised by the
        Chairman to make appointments on his behalf.

2.      The Rent shall be:

        (a)     until the Review Date the Initial Rent, and

        (b)     during the Review Period, a rent equal to the Rent previously
                payable under this Lease immediately prior to the Review Date or
                such revised rent as may be ascertained in accordance with this
                Schedule whichever shall be the greater.

3.      Such revised rent for the Review Period may be agreed in writing at any
        time between the parties or (in the absence of agreement) determined
        (not earlier than the relevant Review Date) by the Arbitrator.

4.      The revised rent to be determined by the Arbitrator shall be such as he
        shall decide should be the rent at which the Premises might reasonably
        be expected to be let on the open market after the expiry of a rent free
        period of such length as would be negotiated in the open market between
        a willing landlord and a willing tenant at the relevant Review Date for
        the Premises making the Assumptions but disregarding the Disregarded
        Matters and having regard to open market rental values current at the
        Review Date.

5.      The arbitration shall be conducted in accordance with the Arbitration
        Act 1996.

6.      When the Rent shall have been ascertained in accordance with this
        Schedule, memoranda thereof shall be signed by or on behalf of the
        parties and annexed to this Lease and its counterpart and the parties
        shall bear their own costs in respect of this.

7.      If the revised rent payable on and from any Review Date has not been
        ascertained by that Review Date, Rent shall continue to be payable at
        the rate previously payable (such payments being on account of the Rent
        for that Review Period), and forthwith upon the revised rent being
        ascertained (that is to say the date when the same has been agreed
        between the parties or the date of the Arbitrator's award), the Tenant
        shall pay to the Landlord any shortfall between what would have been
        paid on the Review Date and on any subsequent rent





                                       40

<PAGE>   42
        days, had the revised rent been determined, and the payment made by the
        Tenant on account together with Interest (interest at the Base Rate of
        the Bank referred to in or nominated pursuant to clause 1.9 prevailing
        on the day upon which the shortfall is paid) on each instalment of Rent
        due on or after the Review Date on the difference between what would
        have been paid on that rent day, had the revised rent been determined,
        and the amount paid on account the interest being payable for the period
        from that date upon which the instalment was due up to the date of
        payment of the shortfall.

8.      If at any of the Review Dates there shall be in force a statute which
        shall prevent restrict or modify the Landlord's right to review the Rent
        in accordance with this Lease and/or to recover any increase in the
        Rent, the Landlord shall when such restriction or modification is
        removed, relaxed or modified be entitled (but without prejudice to its
        rights - if any - to recover any rent the payment of which has only been
        deferred by law) on giving not less than one month's notice in writing
        to the Tenant (at any time within 6 months (time being of the essence in
        this regard) of the restriction or modification being removed relaxed or
        modified) to proceed with any review of the Rent which may have been
        prevented or further to review the Rent in respect of any review where
        the Landlord's right was restricted or modified and the date specified
        in the said notice shall be deemed for the purposes hereof to be a
        Review Date (providing that nothing herein shall be construed as
        varying any subsequent Review Dates except any Review Dates where such a
        statute shall be in force in which event the provisions of this
        paragraph shall apply) and the Landlord shall be entitled to recover any
        resulting increase in Rent with effect from the earliest date as shall
        be permitted by law.



                                       41
<PAGE>   43

                                 FIFTH SCHEDULE

                              The Office Covenants

1.      Repair etc and Decoration

        1.1     Not to cut injure alter or remove any of the Building.

        1.2     In every Decorating Year and in the last year of the Term to
                redecorate the Premises in good and workmanlike manner and with
                appropriate materials of good quality (to the reasonable
                satisfaction of the Surveyor) all tints colours and patterns to
                be approved by or on behalf of the Landlord in writing (such
                approval not to be unreasonably withheld or delayed).

        1.3     To clean the inside of all windows (and the inside of all window
                frames) in the Premises at least once in every month.

        1.4     To employ for the cleaning of the Premises only such firm or
                company as shall be approved by the Landlord (such approval not
                to be unreasonably withheld or delayed).

2.      User

        2.1     Not to use the Premises for any purpose other than as offices
                within Classes 2 or 3 of the Schedule to the Planning (Use
                Classes) Order (Northern Ireland) 1989 and/or for the use of a
                software company.

        2.2     Not to play or use any musical instrument loudspeaker tap
                recorder gramophone radio or other equipment or apparatus that
                produces sound in the Premises so as to be heard in nearby
                premises or outside the Premises.

        2.3     Not to cease to carry on business in the Premises or have them
                vacant for longer than 14 days without:

                (a)     notifying the Landlord; and

                (b)     providing such caretaking or security arrangements as
                        the Landlord shall reasonably require in order to
                        protect the Premises from vandalism theft damage or
                        unlawful occupation.



                                       42
<PAGE>   44

3.      Aerials, Signs and Advertisements

        3.1     Not without the prior written consent of the Landlord (such
                consent not to be unreasonably withheld or delayed) to erect any
                pole mast or wire (whether in connection with telegraphic,
                telephonic, radio or television communication or otherwise) upon
                any part of the outside of the Building.

        3.2     Not to affix or to exhibit on the outside of the Building or to
                or through any window of the Premises or Building any placard
                sign notice fascia board or advertisement except the approved
                sign referred to in paragraph 3.3 of this Schedule.

        3.3     At all times to display and maintain a suitable sign showing the
                Tenant's trading name and business of a size and kind first
                approved by the Surveyor (such approval not to be unreasonably
                withheld or delayed) and at a point with the Building to be
                reasonably specified in writing by him.

4.      Common Parts

        4.1     Not to cause the Common Parts (or any other land roads or
                pavements adjoining on the Premises) to become untidy or in a
                dirty condition but at all times to keep the Common Parts and
                other land, roads or pavements free from deposits of materials
                and refuse.

        4.2     Not to place deposit or expose outside any part of the Premises
                any goods materials articles or things whatsoever for display or
                sale or for any other purpose nor cause any obstruction of the
                Common Parts.

5.      Pollution

        Not to permit to be discharged into the Pipes any oil or grease, or any
        deleterious, objectionable, dangerous, poisonous or explosive matter or
        substance, and to take all reasonable measures to ensure that effluent
        discharged into the Pipes will not be corrosive or otherwise harmful to
        the Pipes or cause obstruction to them.

6.      Roof and Floor Weighting

        6.1     Not without the consent in writing of the Landlord to:



                                       43
<PAGE>   45

                (a)     suspend any undue weight from the walls or ceilings of
                        the Building or use the same for the storage of goods or
                        place any undue weight on them; or

                (b)     have on the Premises any safes, machinery, goods or
                        other articles which may unduly strain or damage the
                        Premises.

        6.2     On any application by the Tenant for the Landlord's consent
                under paragraph 6.1, the Landlord shall be entitled to consult
                and obtain the advice of an engineer or other person in relation
                to the roof or floor loading proposed by the Tenant and the
                Tenant shall repay to the Landlord on demand the fees of such
                engineer or other person.

7.      Machinery

        7.1     Not to install or use in or upon the Premises any machinery or
                apparatus which will cause noise or vibration which can be heard
                or felt in nearby premises or outside the Premises or which may
                cause structural damage.

        7.2     To keep all machinery and equipment upon the Premises properly
                maintained and in good working order, and for that purpose to
                employ reputable contractors for the regular periodic inspection
                and maintenance of them, to renew all working and other parts as
                and when necessary or when recommended by such contractors, to
                ensure by directions to the Tenant's staff and otherwise that
                such plant, apparatus and machinery is properly operated, and to
                avoid damage to the Premises by vibration or otherwise.

8.      Unloading and Parking

                Not to load or unload any goods or materials onto or from
                vehicles and convey the same into the Building and the Premises
                except through the entrances designated as service entrances
                from time to time by the Landlord or the Surveyor (and by means
                of any lift designated for such purposes).

9.      Heating and Cooling Ventilation

        9.1     Not to do anything which interferes with the heating cooling or
                ventilation of the Common Parts or which imposes an additional
                load on the heating cooling or ventilation plant and equipment.



                                       44
<PAGE>   46

        9.2     During the Permitted Hours to operate the ventilation equipment
                in the Premises which comprises part of the system for the air
                conditioning of the Common Parts in accordance with the
                regulations for such purpose made by the Landlord from time to
                time.

10.     Regulations

                To comply with all reasonable regulations made by the Landlord
                from time to time for the management of the Building provided
                that in the event of conflict between such regulations and the
                terms of this Lease then the terms of this Lease shall apply.



                                       45
<PAGE>   47

                                 SIXTH SCHEDULE

                                  The Services

        Maintaining etc Retained Parts

1.      Maintaining, repairing, (and where beyond economic repair or necessary
        to comply with statutory requirements) renewing and replacing and, where
        appropriate, painting and decorating (to such standard as the Landlord
        may reasonably from time to time consider adequate) the Retained Parts.

        Lift

2.      Providing a lift service during the Permitted Hours by the operation of
        the lifts now installed in the Building or (where the existing lifts are
        beyond economic repair or necessary to comply with statutory
        requirements) by such substituted lifts as the Landlord may from time to
        time decide to install.

3.      Hot and Cold Water

        Maintaining during the Permitted Hours an adequate supply of hot and
        cold water and supplying necessary washing and toilet requisites in the
        toilet accommodation situate in the Retained Parts.

4.      Central Heating

        Supplying during the Permitted Hours central heating to the Premises and
        the Common Parts.

5.      Maintaining etc Apparatus, Plant, Machinery etc

        Inspecting, servicing, maintaining, repairing, amending, overhauling,
        (and where beyond economic repair or necessary to comply with statutory
        requirements renewing and replacing, and insuring (save in so far as
        insured under other provisions of this Lease) all apparatus, plant,
        machinery and equipment within the Retained Parts from time to time
        including (without prejudice to the generality of the foregoing) lifts,
        lift shafts, stand-by generators and boilers and items relating to
        mechanical ventilation, heating, cooling, public address, closed circuit
        television (if any).



                                       46
<PAGE>   48

6.      Maintaining etc Pipes

        Maintaining, repairing, cleansing, emptying, draining, amending and
        renewing all Pipes in or serving the Building except those that are
        within and solely serve the Premises or any part of the Building that is
        let or intended for letting.

7.      Maintaining etc Fire Alarms etc

        Maintaining, repairing, replacing and renewing any fire alarms and
        ancillary apparatus, fire prevention and fire fighting equipment, and
        other apparatus in the Retained Parts.

8.      Cleaning etc Retained Parts

        Cleaning, treating, polishing, heating, ventilating and lighting the
        Retained Parts to such standard as the Landlord may from time to time
        consider adequate.

9.      Fixtures Fittings etc

        Supplying, providing, purchasing, hiring, maintaining, renewing,
        replacing, repairing, servicing, overhauling and keeping in good and
        serviceable order and condition all appurtenances, fixtures, fittings,
        bins, receptacles, tools, appliances, materials, equipment and other
        things which the Landlord may deem desirable or necessary for the
        maintenance, appearance, upkeep or cleanliness of the Building or any
        part of it.

10.     Windows

        Cleaning as frequently as the Landlord shall in its reasonable
        discretion consider adequate the exterior of all windows in the Building
        and interior and exterior of all windows and window frames in the
        Retained Parts.

11.     Refuse

        Collecting and disposing of refuse from the Building and the provision,
        repair, maintenance, and renewal of plant and equipment for the
        collection, treatment, packaging, or disposal of refuse.

12.     Additional

        Such other services relating to the Building as the Landlord shall from
        time to time reasonably deem necessary or desirable and not expressly
        mentioned herein.



                                       47
<PAGE>   49

        Provided Always that all services shall be provided by the Landlord in
        accordance with the principles of good estate management.




























                                       48
<PAGE>   50

                                SEVENTH SCHEDULE

                         Additional items of Expenditure

1.1     Fee

        The reasonable fees and disbursements (and any VAT payable thereon) of:

        (a)     the Surveyor and any other individual firm or company employed
                or retained by the Landlord for (or in connection with) such
                surveying or accounting functions, or the management of the
                Building;,

        (b)     the managing agents whether or not the Surveyor for (or in
                connection with):

                (i)     the management of the Building;

                (ii)    the collection of the rents and all other sums due to
                        the Landlord from the tenants of the Building;

                (iii)   the performance of the Services and any other duties in
                        and about the Building or any part of it relating to
                        (without prejudice to the generality of the foregoing)
                        the general management, administration, security,
                        maintenance, protection, cleanliness of the Building;

        (c)     any other individual firm or company employed or retained by the
                Landlord to perform (or in connection with) any of the Services
                or any of the functions or duties referred to in this paragraph.

1.2     The reasonable fees of the Landlord or a Group Company for any of the
        Services or the other functions and duties referred to in paragraph 1.1
        above that shall be undertaken by the Landlord or a Group Company and
        not by a third Party.

2.      Staff etc

        The reasonable cost of employing (whether by the Landlord, a Group
        Company, the managing agents or any other individual firm or company)
        such staff as the Landlord may reasonably deem necessary for the
        performance of the Services and the other functions and duties referred
        to in paragraph 1.1 above and all other incidental expenditure in
        relation to such employment or the termination thereof.



                                       49
<PAGE>   51

3.      Outgoings

        All existing and future rates, water rates, charges, duties,
        assessments, impositions and other outgoings payable by the Landlord in
        respect of the Building or any part of it (excluding the Premises and
        any other part of the Building that is let or intended for letting)
        including (but without prejudice to the generality of the foregoing)
        residential accommodation for caretakers engineers and other staff
        employed in connection with the Building.

4.      Electricity and Gas etc

        The cost of the supply of electricity gas oil or other fuel for the
        provision of the Services and for all purposes in connection with the
        Retained Parts.

S.      Road etc Charges

        The amount which the Landlord shall be called upon to pay as a
        contribution towards the expense of making, repairing, maintaining,
        rebuilding and cleansing any ways roads pavements or structures Pipes
        party fences walls or anything which may belong to or be used for the
        Building or any part of it exclusively or in common with other premises
        near or adjoining the Building.

6.      Regulations

        The costs charges and expenses of preparing and supplying to the tenants
        copies of any Regulations made by the Landlord relating to the Building
        or the use of it.

7.      Statutory etc Requirements

        The cost of taking all steps deemed desirable or expedient by the
        Landlord for complying with, making representations against, or
        otherwise contesting the incidence of the provisions of any regulation,
        byelaw notice, legislation, order or statutory requirements concerning
        town planning, public health, highways, streets, drainage or other
        matters relating or alleged to relate to the Building or any part of it
        for which any tenant is not directly liable.

8.      Nuisance

        The cost to the Landlord of abating a nuisance in respect of the
        Building or any part of it in so far as the same is not the liability of
        any individual tenant.

9.      Anticipated Expenditure



                                       50

<PAGE>   52

Such provision (if any) for anticipated expenditure in respect of any of the
Services or the above mentioned matters as the Landlord shall in its reasonable
discretion consider appropriate.

SEALED with the COMMON SEAL
of DERAMORE HOLDINGS LIMITED
in the presence of:-

SEALED with the COMMON SEAL of
PIVOTAL CORPORATION (NI) LIMITED
in the presence of:-

SEALED with the COMMON SEAL of
PIVOTAL CORPORATION
in the presence of:-


                                      -51-


<PAGE>   53


We, THE GOVERNOR AND COMPANY OF THE BANK OF IRELAND, as Mortgagee hereby consent
to the within Lease.

Dated     day of              2000




-----------------------------------
Authorised Signatory


                                       52
<PAGE>   54



                         [DERAMORE PROPERTY GROUP LOGO]

14th April 2000

Pivotal Corporation Limited,
Hamilton House,
111 Marlowes,
Hemel Hempstead,
Hertfordshire.
HP1 1BD.

Dear Sirs,

THIRD FLOOR CAPITAL HOUSE, 3 UPPER QUEEN STREET, BELFAST

In consideration of you agreeing to take a lease of the above premises on the
agreed terms, we confirm that we shall permit you to take occupation of the
whole of the premises at 9 am on 17 April 2000 and we shall grant to you a lease
in the form annexed hereto and shall complete the same within 28 days.

We further agree as follows:

1. We shall, at our own expense, install a 24-hour card access system at the
   main door of the building to a specification notified to you. The system
   shall be installed within 21 days of you taking occupation of the premises
   and the cost of installation shall be added to the Service Charge.

2. As regards the Service Charge, we confirm as follows:

   2.1 No major capital expenditure is currently planned for the building.

   2.2 During the term of the Lease we shall give you reasonable prior notice of
       any individual item of capital expenditure under the Service Charge which
       is likely to exceed (pound) 100,000.00 and shall consult with you
       thereon.

   2.3 We confirm that the present Service Charge estimates are based on
       (pound)3 per square foot.


                                 41 ROYAL AVENUE
                                 BELFAST BT1 1FB
                      TEL: 028 90 244030 FAX: 028 90243652
                              Email@deramore.co.uk


<PAGE>   55


   2.4 We confirm that the cost of the presently anticipated restructuring and
       refurbishment of the ground floor area shall not be added to Service
       Charge and Service Charge shall not include any other building costs
       which arise as a result of such works.

3. We approve the drawings and specifications of your fit out, subject to same
   meeting statutory requirements.

On any future disposal of our interest in Capital House, we shall procure that
the relevant purchaser shall provide you with a side-letter incorporating points
2.1 and 2.4 (in so far as same relates to the present refurbishment programme at
the date hereof) of this letter.



Signed on behalf of
Deramore Holdings Limited


/s/ [SIGNATURE ILLEGIBLE]
--------------------------------------

We accept and confirm the foregoing conditions

Dated day of 2000

Signed on Behalf of Pivotal Corporation Limited


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

Signed on Behalf of Pivotal Corporation

Dated day of 2000

<PAGE>   56
                                                       Deramore Holdings Limited
                                                       160 Brompton Road
                                                       Knightsbridge
                                                       London
                                                       SW3 1RP

                                                       14 April 2000

Pivotal Corporation Limited
Hamilton House
111 Marlowes
Hemel Hempstead
Hertfordshire
HP1 1BD

BY POST & FAX

Dear Sirs

THIRD FLOOR CAPITAL HOUSE 3 UPPER QUEEN STREET BELFAST

In consideration of you agreeing to take a lease of the above premises on the
agreed terms, we confirm that we shall permit you to take occupation of the
whole of the premises at 9 am on 17 April 2000 and we shall grant to you a
lease in the form annexed hereto and shall complete the same within 28 days.

We further agree as follows:

1    We shall, at our own expense, install a 24-hour card access system at the
     main door of the building to a specification notified to you. The system
     shall be installed within 21 days of you taking occupation of the premises
     and the cost of installation shall not be added to the Service Charge.

2    As regards the Service Charge, we confirm as follows:

     2.1  No major capital expenditure is currently planned for the building.

     2.2  During the term of the Lease we shall give you reasonable prior notice
          of any individual item of capital expenditure under the Service Charge
          which is likely to exceed (pound sterling)100,000.00 and shall
          consult with you thereon.


<PAGE>   57

     2.3  We confirm that the present Service Charge estimates are based on
          (pound sterling)3 per square foot.

     2.4  We confirm that the cost of the presently anticipated restructuring
          and refurbishment of the ground floor area shall not be added to
          Service Charge and Service Charge shall not include any other
          building costs which arise as a result of such works.

3    We approve the drawings and specifications of your fit out, subject to
     same meeting statutory requirements.

     On any future disposal of our interest in Capital House, we shall procure
     that the relevant purchaser shall provide you with a side-letter
     incorporating points 2.1 and 2.4 (in so far as same relates to the present
     refurbishment programme at the date hereof) of this letter.

Signed on behalf of
Deramore Holdings Limited

We accept and confirm the foregoing conditions

Dated 14 day of April 2000

Signed on Behalf of Pivotal Corporation Limited


 /s/ VINCENT MIFSUD                 VINCENT MIFSUD
-----------------------------

/s/ VINCENT MIFSUD                  VINCENT MIFSUD

Signed on Behalf of Pivotal Corporation

Dated 14 day of April 2000

<PAGE>   58
                                  [STREET MAP]

<PAGE>   59
                               [THIRD FLOOR PLAN]