<PAGE>

                                                                    Exhibit 10.4

[LOGO] NatWest

                                                        Legal Charge
                                                        Secs 3 Commercial (7/95)

THIS IS AN IMPORTANT DOCUMENT. YOU SHOULD TAKE INDEPENDENT LEGAL ADVICE BEFORE
SIGNING AND SIGN ONLY IF YOU WANT TO BE LEGALLY BOUND. IF YOU SIGN AND THE BANK
IS NOT PAID YOU MAY LOSE THE ASSET(S) CHARGED.

Date: 17th December 2001

Definitions

Mortgagor:               Bottomline Technologies Europe Limited
                                                        Company Number: 01911956

Bank:                    National Westminster Bank Plc

Interest:                Interest at the rate(s) charged to the Mortgagor by the
                         Bank for time to time

Property:                Administrative Area :      Reading

                         Description         :      115 Chatham Street

                         Tenure              :      Freehold

                         Title Number        :      BK110384

Charged Assets:          The assets charged by Clause 1.2

Goodwill:                The present and future goodwill of any business carried
                         on at the Property by or on behalf of the Mortgagor

Mortgagor's              Obligations: All the Mortgagor's liabilities to the
                         Bank of any kind and in any currency (whether present
                         or future actual or contingent and whether incurred
                         alone or jointly with another) together with the Bank's
                         charges and commission Interest and Expenses

Expenses:                All expenses (on a full indemnity basis) incurred by
                         the Bank or any Receiver at any time in connection with
                         the Property the Charged Assets the Goodwill or the
                         Mortgagor's Obligations or in taking or perfecting this
                         deed or in preserving defending or enforcing the
                         security created by this deed or in exercising any
                         power under this deed or otherwise with Interest from
                         the date they are incurred.

Required Currency:       The currency or currencies in which the Mortgagor's
                         Obligations are expressed from time to time

Charge

1       The Mortgagor covenants to discharge on demand the Mortgagor's
        Obligations and as a continuing security for such discharge and with
        full title guarantee charges to the Bank:-

1.1     By way of legal mortgage of all legal interests and otherwise by way of
        fixed charge the Property (to the full extent of the Mortgagor's
        interest in the Property or its proceeds of sale)

1.2     By way of fixed charge if the Mortgagor is a company:-

1.2.1   All the plant machinery and fixtures and fittings of the Mortgagor now
        and in the future at the Property

1.2.2   All furniture furnishings equipment tools and other chattels of the
        Mortgagor now and in the future at the Property and not regularly
        disposed of in the ordinary course of business

1.3     By way of fixed charge the Goodwill and the proceeds of any insurance
        from time to time affecting the Property or the Charged Asset

<PAGE>

Repair Alteration and Insurance

2.1     The Mortgagor will keep the Property and the Charged Assets in good
        condition and comprehensively insured to the Bank's reasonable
        satisfaction for their full reinstatement cost and in default the Bank
        (without becoming liable to account as mortgagee in possession) may
        enter and repair or insure the Property and the Charged Assets. The
        Mortgagor will deposit with the Bank the insurance policy or where the
        Bank agrees a copy of it

2.2     The Mortgagor will not without the prior written consent of the Bank
        make any alteration to the Property which would require Planning
        Permission or approval under any Building Regulations

2.3     The Mortgagor will hold in trust for the Bank all money received under
        any insurance of the Property or the Charged Assets and at the Bank's
        option will apply the same in making good the relevant loss or damage or
        in or towards discharge of the Mortgagor's Obligations

Restrictions on Charging Leasing Disposing and Parting with possession

3.1     The mortgagor will not without the Bank's prior written consent:-

3.1.1   Create or permit to arise any mortgage charge or lien on the Property
        the Charged Assets or the Goodwill

3.1.2   Grant or accept a surrender of any lease or licence of the Property the
        Charged Assets or the Goodwill

3.1.3   Dispose of or part with or share possession or occupation of the
        Property the Charged Assets or the Goodwill

3.2     The Mortgagor requests the Chief Land Registrar to enter a restriction
        on the Register of any Registered Land that except under an order of the
        Registrar no disposition by the proprietor(s) of the land is to be
        registered without the consent of the registered proprietor of this deed

Powers of the Bank

4.1     The Bank may without restriction grant or accept surrenders of leases of
        the Property and the Charged Assets

4.2     Section 103 of the Law of Property Act 1925 shall not apply and the Bank
        may exercise its power of sale and other powers under that or any other
        Act or this deed at any time after the date of this deed

4.3     The Bank may under the hand of any official or manager or by deed
        appoint or remove a Receiver or Receivers of the Property the Charged
        Assets and the Goodwill and may fix and pay the fees of a Receiver but
        any Receiver shall be deemed to be the agent of the Mortgagor and the
        Mortgagor shall be solely responsible for the Receiver's acts defaults
        and remuneration

4.4     All or any of the powers conferred on a Receiver by Clause 5 may be
        exercised by the Bank without first appointing a Receiver or
        notwithstanding any appointment

4.5     The Bank will not be liable to account to the Mortgagor as mortgagee in
        possession for any money not actually received by the Bank

4.6     Section 93(1) of the Law of Property Act 1925 shall not apply to this
        deed

4.7     In addition to any lien or right to which the Bank may be entitled by
        law the Bank may from time to time without notice and both before and
        after demand set off the whole or any part of the Mortgagor's
        Obligations against any deposit or credit balance on any account of the
        Mortgagor with the Bank (whether or not that deposit or balance is due
        to the Mortgagor)

4.8     Despite any term to the contrary in relation to any deposit or credit
        balance on any account of the Mortgagor with the Bank that deposit or
        balance will not be capable of being assigned dealt with mortgaged or
        charged and will not be repayable to the Mortgagor before all the
        Mortgagor's Obligations have been discharged but the Bank may without
        prejudice to this deed permit the Mortgagor to make withdrawals from
        time to time

4.9     The Bank may exchange or convert to the Required Currency any currency
        held or received

Receivers

5.1     Any Receiver appointed by the Bank shall (in addition to all powers
        conferred on him by law) have the following powers which in the case of
        Joint Receivers may be exercised jointly or severally:-


<PAGE>

5.1.1   To take possession of and generally manage the Property and the Charged
        Assets and any business carried on at the Property

5.1.2   To carry out on the Property any new works or complete any unfinished
        works of building reconstruction maintenance furnishing or equipment

5.1.3   To purchase or acquire any land or other property and purchase acquire
        grant or release any interest in or right over land or the benefit of
        any covenants (positive or restrictive) affecting land

5.1.4   To sell lease surrender or accept surrenders of leases charge or
        otherwise deal with and dispose of the Property the Charged Assets and
        the Goodwill without restriction including (without limitation) power to
        dispose of any fixtures separately from the Property

5.1.5   To carry into effect and complete any transaction by executing deeds or
        documents in the name of or on behalf of the Mortgagor

5.1.6   To take continue or defend any proceedings and enter into any
        arrangement or compromise

5.1.7   To insure the Property and the Charged Assets and any works and effect
        indemnity insurance or other similar insurance and obtain bonds and give
        indemnities and security to any bondsmen

5.1.8   To employ advisers consultants managers agents workmen and others and
        purchase or acquire materials tools equipment goods or supplies

5.1.9   To borrow any money and secure the payment of any money in priority to
        the Mortgagor's Obligations for the purpose of the exercise of any of
        his powers

5.1.10  To do any other acts which the Receiver may consider to be incidental or
        conductive to any of his powers or to the realization of the Property
        the Charge Assets and the Goodwill

5.2     If the Mortgagor is not a company the Mortgagor grants to such Receiver
        an irrevocable licence and power to use in connection with any business
        carried on at the Property all property of the Mortgagor at the Property
        when the Receiver is appointed and to remove store sell and/or dispose
        of any such property. The Receiver will account to the Bank for the
        proceeds of any sale of such property after deducting all costs and
        expenses incurred in the sale and that amount shall be a debt due from
        the Bank to the Mortgagor

5.3     A Receiver shall apply all money he receives first in repayment of all
        money borrowed by him and his expenses and liabilities and in payment of
        his fees and secondly towards the remaining matters specified in Section
        109(8) of the Law of Property Act 1925

Power of Attorney

6       The Mortgagor irrevocably appoints the Bank and any Receiver severally
        to be the Attorney of the Mortgagor (with full power of substitution and
        delegation) in the Mortgagor's name and on the Mortgagor's behalf and as
        the Mortgagor's act and deed to sign or execute all deeds instruments
        and documents or take continue or defend any proceedings which may be
        required by the Bank or any Receiver pursuant to this deed or the
        exercise of any of their powers

Appropriation

7.1     Subject to Clause 7.2 the Bank may appropriate all payments received for
        the account of the Mortgagor in reduction of any part of the Mortgagor's
        Obligations as the Bank decides

7.2     The Bank may open a new account or accounts upon the Bank receiving
        actual or constructive notice of any charge or interest affecting the
        Property the Charged Assets or the Goodwill. Whether or not the Bank
        opens any such account no payment received by the Bank after receiving
        such notice shall (if followed by any payment out of or debit to the
        relevant account) be appropriated towards or have the effect of
        discharging any part of the Mortgagor's Obligations outstanding at the
        time of receiving such notice

Preservation of other Security and Rights and Further Assurance

8.1     This deed is in addition to any other security present or future held by
        the Bank for the Mortgagor's Obligations and shall not merge with or
        prejudice such other security or any contractual or legal rights of the
        Bank

<PAGE>

8.2   The Mortgagor will at the Mortgagor's own cost at the Bank's request
      execute any deed or document and take any action required by the Bank to
      perfect this security or further to secure the Mortgagor's Obligations on
      the Property the Charged Assets and the Goodwill

Memorandum and Articles of Association

9     If the Mortgagor is a company the Mortgagor certifies that this deed does
      not contravene the Mortgagor's Memorandum and Articles of Association

Notices

10.1  Any notice or demand by the Bank may be sent by post or fax or delivered
      to the Mortgagor at the Mortgagor's address last known to the Bank or if
      the Mortgagor is a company may be served personally on any director or the
      secretary of the Mortgagor

10.2  A notice or demand by the Bank by post shall be deemed served on the day
      after posting

10.3  A notice or demand by the Bank by fax shall be deemed served at the time
      of sending

Governing Law

11    This deed shall be governed by and construed in accordance with English
      law

Interpretation

12.1  The expressions "Mortgagor" and "Bank" where the context admits include
      their respective successors in title and assigns

12.2  If two or more persons are included in the expression "Mortgagor" then the
      use in this deed of the word "Mortgagor" shall be deemed to refer to such
      persons both together and separately and the Mortgagor's Obligations shall
      be their joint and several obligations and each of them shall be primarily
      liable by way of indemnity for the liabilities to the Bank of the other or
      others of them

12.3  References to the "Property" and the "Charged Assets" include any part of
      it or them and the "Property" includes all covenants and rights affecting
      or concerning the same. The "Property" also includes any share from time
      to time held by the Mortgagor in any landlord or management company of the
      Property

12.4  Interest will be calculated both before and after demand or judgment on a
      daily basis and compounded according to agreement or in the absence of
      agreement monthly on such days as the Bank may select

12.5  Each of the provisions of this deed shall be severable and distinct from
      one another and if one or more of such provisions is invalid or
      unenforceable the remaining provisions shall not in any way be affected

In Witness of which this deed has been duly executed


         /s/ P. Fortune
         ---------------
         Director

         /s/ S.J. Cutler
         ---------------
         Secretary/Director

         (Please ensure this document is dated)

Signed and Delivered as a deed by the Mortgagor acting by a director and its
secretary or two directors