EASTERN
[LOGO]

                                                              Eastern Group plc
                                                              Wherstead Park
                                                              PO Box 40
                                                              Wherstead
                                                              Ipswich
                                                              Suffolk IP92AQ


To:            Barclays Bank PLC as Agent under the Guarantee and Indemnity.

Copied to:     the Banks (as defined in the Guarantee and Indemnity (as defined
               below)


                                                                   17 July 1998

Dear Sirs

EASTERN MERCHANT PROPERTIES LIMITED ("EMPL") RENT FACTORING TRANSACTION (THE
"RFT") DATED 28 OCTOBER 1996

We refer to the Guarantee and Indemnity dated 28 October 1996 (the "Guarantee
and Indemnity") relating to the RFT, and we are requesting the consent of the
Banks and the Participants to certain changes to the terms of the Guarantee and
Indemnity.

Eastern Group plc, EMPL, Eastern Electricity plc and Eastern Generation Limited
as signatories to this letter.

(a)  confirm their agreement to the terms of this letter; and

(b)  make the representations and warranties referred to in paragraph 4.


Capitalised terms not otherwise defined in this letter shall where the context
so permits have the meanings given to them in the Guarantee and Indemnity. In
this letter

     "EFFECTIVE DATE" means the date on which the Agent confirms to each Bank
     and EMPL that

     (a)  the Banks and Participants have agreed to the matters referred to in
          this letter (after taking into account any proposed transfers between
          Banks and/or between Participants); and

     (b)  the condition precedent under paragraph 3 below has been satisfied.


     "RELEVANT PARTICIPANT" means, in the case of each Bank, each Participant
     from time to time party to a Participation Agreement with that Bank.


1.   In  consideration of the fees referred to in paragraph 2 below, we request
     your consent to the amendments and waivers of the terms of the Guarantee
     and Indemnity set out in Schedule 1 to this letter with effect on and from
     the Effective Date.






2.   (a)  From and including the Effective Date, EMPL shall pay a waiver fee
          (the "WAIVER FEE") to the Agent for the account of each Bank and its
          Relevant Participants calculated in accordance with sub-paragraphs (b)
          and (c) below.

     (b)  The Waiver Fee shall accrue from day to day from the Effective Date on
          the basis of a 365 day  year, and the accrued Waiver Fee shall be
          payable on each Rent Day falling after the Effective Date.

     (c) (i)        The Waiver Fee payable on each Rent day shall be calculated
                    by the Agent at the rate of the Waiver Fee Percentage on the
                    National Principal (as at the preceding Rent Day) for the
                    period from (and including) the preceding Rent Day (or, if
                    later, the Effective Date) to (and excluding) the relevant
                    Rent Day on which that payment is made. The Waiver Fee
                    Percentage is defined under, and calculated in accordance
                    with, subparagraph (ii) below.

          (ii)      If the ratio of Total Consolidated Net Borrowings (as
                    defined in the Guarantee and Indemnity as amended by this
                    letter) to Adjusted Tangible Consolidated Net Worth (as so
                    defined and, subject to sub-paragraph (iii) below, each as
                    calculated by the Agent by reference to the accounts or
                    half-yearly accounts most recently delivered to the Agent
                    under Clause 4.1(a) and (b) of the Guarantee and Indemnity
                    on or prior to the Rent Day immediately preceding the Rent
                    Day on which the waiver fee is payable) is within a range
                    set out in column I below, the Waiver Fee Percentage shall
                    be the rate per annum set out in column II below opposite
                    that range:


                       I                                             II

               Greater than 125%                                0.50 per cent
               Greater than 100% but less than or               0.375 per cent
               equal to 125%
               100% or less                                     0.25 per cent


          (iii)     For the purposes of calculating the Waiver Fee, the ratio of
                    Total Consolidated Net Borrowings to Adjusted Tangible
                    Consolidated Net Worth shall be deemed to be greater than
                    100% at all times for a period of 6 months following the
                    Effective Date.

          (iv)      The Waiver Fee is exclusive of Value Added Tax or any other
                    tax which might be chargeable in connection with that fee.
                    If any Value Added Tax or other similar tax is so
                    chargeable, it shall (subject to receipt of a valid Value
                    Added Tax Invoice) be paid by EMPL at the same time as it
                    pays the relevant fee.


     (d)  Each Guarantor, jointly end severally, as principal obligor guarantees
          to each Bank that EMPL, shall make each payment of the Waiver Fee when
          due. Each Guarantor, jointly and severally, as principal obligor
          irrevocably and  unconditionally  indemnifies each Bank and each
          Participant against any loss or liability suffered by it if that
          payment obligation guaranteed by a Guarantor is or becomes
          unenforceable, invalid or illegal. The provisions of Schedule 3 shall
          apply to this paragraph 2(d).


                                       -2-




3.   The obligaions of each Bank under this letter are subject to the condition
     precedent that the Agent has confirmed to the Banks that it has received
     all of the documents set out in Schedule 2 to this letter in form and
     substance satisfactory to it.

4.   EMPL represents and warrants to each Bank in the terms set out in clauses
     7(a) to (c) of the Assignment (mutatis  mutandis) but as if a reference in
     those  clauses to the Deed was a reference to this letter.  Each Guarantor
     represents and warrants jointly and severally to each Bank in the Terms and
     subject to the limitations set out in clauses 3.1 and 3.2 of the Guarantee
     and Indemnity (mutatis mutandis) but as if a reference in those clauses to
     any Transaction Document were a reference to this letter.

5.   This letter is supplemental to the Guarantee and Indemnity and on and from
     the Effective Date the terms of this 1etter and the terms of the Guarantee
     and Indemnity shall be read and  construed as one  document. Except  as
     expressly amended or waived by this letter, the Guarantee and Indemnity and
     each of the other Transaction Documents  shall continue in full force and
     effect.

6.   Each of the Guarantors as principal obligor hereby jointly and severally
     agrees irrevocably and unconditionally to indemnify the Agent and each Bank
     and each of their Affiliates in full on receipt of a demand served upon
     each of them in writing, on an after tax basis against a11 liability,
     losses or claims which are suffered or properly incurred by it or a
     Relevant Participant or any of their Affiliates (a "loss") and any costs,
     charges and expenses to which it may be subject or which it may properly
     incur (a "charge") as a consequence of the operation of, or the
     transactions contemplated by, this letter including, without limitation,
     any loss or charge on account of funds borrowed, contracted for or utilised
     to fund any amount payable under any Transaction Document or Participation
     Agreement and any loss or charge incurred as a result of the termination,
     novation, or replacement of all or any part of its interest rate swaps or
     other hedging arrangements relating to the transactions contemplated by the
     Transaction Documents or Participation Agreements.

7.   The provisions of Clauses  21, 23, 25, 29, 30, 31, 32, 34, 35, 36, 37, 38
     and 41 of the Guarantee and Indemnity and Clause 2 of the Assignment shall
     apply to this letter as if set out in full in this letter  (mutatis
     mutandis) but as if references in those provisions to any  Transaction
     Document were references to this letter.

8.   EMPL  undertakes to deliver the  executed original of this letter and its
     counterparts to the Custodian for retention in accordance with the terms of
     the Custody Deed.

9.   This letter and the attached consent forms may be executed in any number of
     counterparts and this shall have the same effect as if all of the
     signatures were on a single copy of this letter.

10.  This letter is governed by English law.

If you agree to the above, please sign this letter and return a copy of it to
us.

Yours faithfully


/s/ E. J. Lean
- ----------------------
Eastern Group plc


                                       -3-




/s/ E. J. Lean
- -----------------------------------
Eastern Merchant Properties Limited


/s/ E. J. Lean
- -----------------------------------
Eastern Certification Limited


/s/ E. J. Lean
- -----------------------------------
Eastern Electricity plc

We accept the amendments and waivers  set out in this  letter (subject to the
terms and conditions set out in this letter) and confirm that we are authorised
to sign this letter as Agent on behalf of, and have  received to requisite
approvals from, the Banks and the Participants in accordance with Clause 31.1 of
the Guarantee and Indemnity.



/s/ L. Kenworthy
- --------------------------------   AS ATTORNEY
Barclays Bank PLC as Agent


                                      -4-





                                   SCHEDULE 1

The following amendments to and waivers of the provisions of the Guarantee and
Indemnity shall come into effect on the Effective Date:

     (a)  the  following new definitions are inserted into Clause 1.1, in
          alphabetical order:

          (i)  "ADJUSTED CONSOLIDATED TANGIBLE NET WORTH" means at any time the
               aggregate of:

               (a)  all amounts paid up or credited as paid up on the issued
                    share capital of Eastern Group plc (excluding Qualifying
                    Preference Shares);

               (b)  any credit balance on profit and loss account; and

               (c)  any other capital and revenue reserves (including those
                    resulting from an upward revaluation  included in the
                    Consolidated Management Accounts, dated 31st March, 1998);

               less the aggregate of:

               (d)  any debit balance on profit and loss account;

               (e)  any amount shown in respect of goodwill (including goodwill
                    arising only on consolidation) or intangible  assets or in
                    respect of minority interests;

               (f)  any reserves set aside for World Tax, deferred World Tax or
                    bad debts;

               (g)  any indebtedness owned by;


                    (i)       The Energy Group PLC;

                    (ii)      a T.U. Company; or

                    (iii)     Texas Utilities Company or any company,
                              partnership or person of which a T.U. Company is a
                              direct or indirect  Subsidiary  Undertaking or any
                              other direct or indirect Subsidiary Undertaking of
                              any such company, partnership or person,

               in each case, to any member of the Group; and

               (h)  the amount of any revaluation or reserve arising from any
                    upward revaluation occurring after 31st March, 1998

               (and so that no amount shall be included or excluded  more than
               once) all as determined from the most recently published audited
               consolidated and


                                       -5-



               interim unaudited consolidated financial statements of Eastern
               Group plc;";

          (ii)      ""CASH" means cash at hand or cash at bank, in each case to
                    the extent free of Encumbrances (other than Encumbrances
                    which secure only Borrowings) and readily remittable to the
                    United Kingdom, but excluding the proceeds of any
                    securitisation of the assets or revenues of any member of
                    the Group to the extent not included as Borrowings;";

          (iii)     ""CHANGE IN CONTROL" shall be deemed to have occurred if:

               (a)  any person or group of related persons (other than Texas
                    Utilities Company, any Subsidiary of Texas  Utilities
                    Company, or any pension,  savings or other employee benefit
                    plan for the benefit of employees of Texas Utilities Company
                    and/or any Subsidiary of Texas Utilities Company) shall have
                    accrued beneficial ownership of more than 30% of the
                    outstanding Voting Shares (within the meaning of section
                    13(d) or 14(d) of the Securities Exchange Act of 1934 of the
                    United  States of America, as amended, and the  applicable
                    rules and regulations thereunder); provided that a Change in
                    Control shall not be deemed to have occurred if such
                    acquisition has been approved, prior to the  Parent
                    Acquisition Date and the date on which any tender offer for
                    Voting Shares of Texas Utilities Company was commenced, by a
                    majority of the Disinterested Directors of Texas Utilities
                    Company; or

               (b)  during any period of 12 consecutive months, commencing
                    before or after 17 July 1998, individuals who on the first
                    day of such period were directors of Texas Utilities Company
                    (together with any replacement or additional directors who
                    were nominated or elected by a majority of directors then in
                    office) cease to constitute a majority of the board of
                    directors of Texas Utilities Company;";

          (iv)      ""DISINTERESTED DIRECTOR" shall mean any member of the Board
                    of Directors of Texas Utilities Company who:

               (a)  is not affiliated, directly or indirectly, with, or
                    appointed by, a person or group of related  persons (other
                    than Texas Utilities Company, any Subsidiary of Texas
                    Utilities Company or any pension, savings or other employee
                    benefit plan for the benefit of employees of Texas Utilities
                    Company  and/or any Subsidiary of Texas Utilities Company)
                    acquiring the beneficial ownership of more than 30% of the
                    outstanding Voting Shares of Texas Utilities Company (within
                    the meaning of section 13(d) or 14(d) of the Securities
                    Exchange Act of 1934 of the United States of America, as
                    amended, and the applicable rules and regulations
                    thereunder); and

               (b)  either was a member of the board of directors of Texas
                    Utilities  Company prior to the Parent Acquisition Date or
                    was recommended for election by a majority of the
                    Disinterested Directors in office prior to time Parent
                    Acquisition Date;";



                                       -6-




          (v)       ""LICENSEE"  means Eastern  Electricity  plc (company number
                    2366906)  or such other  member of the Group  which,  at any
                    time,  is the  licensee  under a PES  License or  Generation
                    License,  any license under section 7 of the Gas Act 1986 or
                    any  replacement  of any such  licence (or, if there is more
                    -than  one  replacement   licence,   the  most  recent  such
                    replacement),  in each  --case as such  licence  is  amended
                    and/or extended from time to time;";

          (vi)      ""PARENT ACQUISITION DATE" shall mean the date as of which a
                    person or group of related  persons first acquires more than
                    30% of the  outstanding  Voting  Share  of  Texas  Utilities
                    Company (within the meaning of section 13(d) or 14(d) of the
                    Securities  Exchange  Act of 1934 of the  United  Stares  of
                    America,   as  amended,   and  `clue  applicable  rules  and
                    regulations thereunder);":

          (vii)     ""TOTAL  CONSOLIDATED NET BORROWING" means, at any time, the
                    aggregate  principal  amount of all  Borrowings of the Group
                    less Cash;";

          (viii)    ""T.U.  COMPANY" means each of T.U.  Finance (No. 1) Limited
                    (company  number  3505836),  T.U.  Finance  (No.  2) Limited
                    (company number 3514100) and T.U.  Acquisitions PLC (company
                    number 3455523);"; and

          (ix)      ""VOTING SHARES" means  outstanding  shares of capital stock
                    of any class of Texas Utilities  Company entitled to vote in
                    the election of directors,  excluding  shares entitled so to
                    vote only upon the happening of some contingency;";

     (b)  Clause 4 1(b) is amended by adding to the end of that clause before
          the semicolon:

                    "and,  together  with such  accounts and the accounts  under
                    paragraph (a) above,  a certificate  signed by two directors
                    of  Eastern  Group  plc  setting  out in  reasonable  detail
                    computations establishing compliance with Clauses 4-1(q) and
                    4.1(t)";

     (c)  existing Clause 4.1(t) is deleted and replaced with:

          "procure that:

          (i)       the Adjusted  Consolidated Tangible Net Worth is not, at any
                    time, less than (pound)800,000,000; and

          (ii)      Total  Consolidated  Net  Borrowings  do not,  at any  time,
                    exceed 150% of Adjusted Consolidated Tangible Net Worth";

     (d)  Clause 4.1(w) is amended to read:

          "not, and shall procure that none of its Subsidiaries shall:

          (i)       give  any  guarantee,  indemnity  or other  legally  binding
                    assurance  against  loss to any  person  in  respect  of the
                    obligations of any Relevant Person; nor


                                      -7-



          (ii)      enter into any transaction  under which (or do anything as a
                    result of or by which) cash or other assets are  transferred
                    by or from it to any  Relevant  Person  provided  that  this
                    sub-paragraph (ii) shall not prohibit:

                    (aa)      the declaration or payment of any lawful dividends
                              or other  distributions or the provision of loans,
                              deposits or other credits but excluding guarantees
                              or  indemnities  entered  into in  favour of or in
                              respect of the indebtedness of the indebtedness of
                              any Relevant Person; or

                    (bb)      anything done  pursuant to a  transaction  entered
                              into on terms no more onerous to Eastern Group plc
                              (or the relevant  Subsidiary)  than a  transaction
                              entered  into on an arm's  length  basis on normal
                              commercial terms;";

     (e)  Clause 5(d) is deleted;

     (f)  the words  "any T.U.  Company"  are  inserted  into the first  line of
          Clause 17-1 (f) immediately after the word "Guarantors" and before the
          words "the Landlord";

     (g)  the words ", the Tenant or Eastern  Electricity plc (formerly  Eastern
          Group plc)" in Clause 17.1(p) are replaced by "or the Tenant";

     (h)  Clause 17.1(r) is deleted and replaced with:

          "(i)      T.U. Acquisitions PLC ceases to be a wholly owned Subsidiary
                    of T.U. Finance (No. 2) Limited; or

          (ii)      T.U.  Finance  (No. 2) Limited  ceased to be a wholly  owned
                    Subsidiary  of  Texas  Utilities   Company  (other  than  as
                    permitted by paragraph (iii) below) and at least a 90% owned
                    direct subsidiary of T.U. Finance (No. 1) Limited; or

          (iii)     less than 100%  (until  19th May,  1999) or 75% (until  19th
                    May, 2000) or 60%  (thereafter)  of the equity share capital
                    of T.U.  Finance (No. 1) Limited is held by Texas  Utilities
                    Company (directly or indirectly) at any time; or

          (iv)      Eastern  Electricity  plc  (company  number  2366906) or any
                    other  Licensee  ceases to be a  wholly-owned  Subsidiary of
                    Eastern Group plc; or

          (v)       Eastern  Group plc ceases to be a direct or indirect  wholly
                    owned Subsidiary of T.U. Acquisitions PLC or Texas Utilities
                    Company; or

          (vi)      there is a Change in Control of Texas Utilities Company";

     (i)  the  outstanding  Event of Default  arising under Clause  17.1(r) as a
          result of the acquisition of The Energy Group PLC by T.U. Acquisitions
          PLC is permanently waived.


                                       -8-



                                   SCHEDULE 2


     (a)  Memoranda and Articles of  Association  of each  Guarantor and EMPL in
          each case  certified  by the company  secretary  of such party to be a
          true copy of the original;

     (b)  a legal opinion from Allen & Overy addressed to the Agent,  the Banks,
          the Participation Agent and the Participants;

     (c)  a  certificate  copy of an  appropriate  resolution  of the  board  of
          directors of each Guarantor and EMPL;

     (d)  payment of all fees in connection  with this letter which are required
          to be paid by EMPL or its Affiliates on or before the Effective Date;

     (e)  a certificate of a director of Eastern Group plc confirming:

          (i)       that no Event of Default is  outstanding as at the Effective
                    Date (except as waived by this letter);

          (ii)      as at 3l March 1998:

                    (A)       that Adjusted  Consolidated  Tangible Net Worth is
                              not less than (pound)800,000,000; and

                    (B)       the ratio of Total  Consolidated Net Borrowings to
                              Adjusted Consolidated Tangible Net Worth; and

                    (C)       the ratio of Consolidated  Profits Before Interest
                              and Tax to  Consolidated  Interest  for the period
                              from 1st April, 1996 to 30th September, 1997,

                    together with calculations in reasonable detail;

          (iii)     that since 30th September,  1997 there has been no change in
                    the  business,  assets or  condition  of itself or any other
                    member of the Group having a Material Adverse Effect; and


     (f)  certified  copies of specimen  Guarantor  and EMPL  signatures of duly
          authorised signatories for each Guarantor and EMPL.


                                       -9-



                                   SCHEDULE 3



     (a)  The  guarantee  set  out in  paragraph  2(d)  (the  "Guarantee")  is a
          continuing  guarantee  and will extend to the ultimate  balance of all
          sums payable by EMPL under this letter, regardless of any intermediate
          payment or discharge in whole or in part.

     (b)  (i)       Where any discharge  (whether in respect of the  obligations
                    of EMPL, or any security for those obligations or otherwise)
                    is made in whole or in part or any  -arrangement  is made on
                    the  faith of any  payment,  security  or other  disposition
                    which  is  avoided  or  must  be  restored  on   insolvency,
                    liquidation or otherwise without  limitation,  the liability
                    of the Guarantors  under the Guarantee  shall continue as if
                    the discharge or arrangement had not occurred.

          (ii)      Each Bank and the Agent may concede or compromise  any claim
                    that any payment, security or other disposition is liable to
                    avoidance or restoration.

     (c)  The  obligations  of each  Guarantor  under the Guarantee  will not be
          affected by any act,  omission,  matter or thing  which,  but for this
          provision, would reduce, release or prejudice any of their obligations
          under the  Guarantee  or prejudice or diminish  those  obligations  in
          whole or in part,  including  (whether or not known to it or any Bank,
          the Agent or any other person):

          (i)       any time or waiver granted to, or composition  with, EMPL or
                    any other person;

          (ii)      the  taking,  variation,  compromise,  exchange,  renewal or
                    release  of, or refusal or  neglect to  perfect,  take up or
                    enforce,  any rights  against,  or security  over assets of,
                    EMPL  or  any  other  person  or  any   non-presentation  or
                    non-observance  of any  formality  or other  requirement  in
                    respect of any instrument or any failure to realise the full
                    value of any security;

          (iii)     any  incapacity  or  lack  of  powers,  authority  or  legal
                    personality  of or  dissolution  or change in the members or
                    status of EMPL or any other person;

          (iv)      any variation  (however  fundamental) or replacement of this
                    letter or any other document or security so that  references
                    to  that  document  in this  Guarantee  shall  include  each
                    variation or replacement;

            (v)     any  unenforceability,   illegality  or  invalidity  of  any
                    obligation of any person under any document or security,  to
                    the  intent  that each  Guarantor's  obligations  under this
                    Guarantee shall remain in full force and its guarantee shall
                    be   construed   accordingly,    as   if   there   were   no
                    unenforceability, illegality or invalidity;

          (vi)      any postponement,  discharge, reduction,  non-provability or
                    other similar circumstance  affecting any obligation of EMPL
                    under this letter resulting from any insolvency, liquidation
                    or dissolution  proceedings  or from any law,  regulation or
                    order so that each such obligation shall for the purposes of
                    each  Guarantor's   obligations   under  this  Guarantee  be
                    construed as if there were no such circumstance.


                                      -10-