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                                                                   EXHIBIT 10.21


                                    BARCLAYS


                                                    London Corporate Banking
                                                    PO Box 15162
                                                    50 Pall Mall
                                                    London SWIA 1QB
                                                    Tel     020 7441 4099
                                                    Fax     020 7441 4225

Independent Energy UK Limited (the COMPANY")

and

Independent Energy Holdings PLC

both of

Radcliffe House
6th Floor
Blenheim Court
Solihull
West Midlands
B91 2AA

Dear Sirs                                                        6th March, 2000

We refer to the facility letter (the "ORIGINAL ANCILLARY FACILITY LETTER") dated
21st October, 1999 between the Company and us (the "BANK", which term includes
our successors, transferees and assigns and each and any branch through which
any part of the facilities contemplated by this letter and/or the Original
Ancillary Facility Letter is made available).

Please countersign this letter (or a copy of it) where marked below to confirm
your agreement that:

(a)      the Original Ancillary Facility Letter is amended as follows with
         immediate effect:

         (i)      the existing paragraph 1 (Facilities) is deleted and replaced
                  by the following:

                  "Overdraft and/or letter of credit lines of (pound)
                  102,000,000 in aggregate.

                  Business Master II Exposure limits:

                           For UK payment to suppliers:   (pound) 3,000,000

                           For UK payments re salaries:   (pound) 600,000

                  Company Barclaycard limit (pound)50,000.



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                  In addition, the existing status of the Company as Direct
                  Debit Originators is confirmed.";

         (ii)     a letter of credit, not exceeding (pound)60,000,000 in
                  aggregate, may be issued to Energy Pool Funds Administration
                  Limited in respect of the Company's obligations under the
                  Pooling and Settlement Agreement for the Electricity Industry
                  in England and Wales dated 30th March, 1990 (the "POOL LC")
                  and the balance of the facility shall be used only to pay
                  related fees and to guarantee contingent liabilities incurred
                  in the ordinary course of trading and for working capital
                  purposes (and the existing paragraph 2 (Purpose) is amended
                  accordingly);

         (iii)    in the existing paragraph 3 (Term) the words "12th January,
                  2000" are deleted and replaced by the following:

                  "the earlier of 6th June, 2000 or one business day after the
                  date on which the proceeds of any equity offering are received
                  by Independent Energy Holdings PLC".

         (iv)     the Company shall:

                  (a)      pay interest on any amount paid by the Bank under the
                           Pool LC issued on the date of this letter (and on any
                           advance made by the Bank to fund any such amount)
                           calculated at a rate of 10% per anum, on the daily
                           unreimbursed balance of that amount (or advance),
                           calculated and compounded on the Bank's usual basis
                           and payable on the last business day of each calendar
                           month; and

                  (b)      without limiting or affecting any of its obligations
                           to the Bank, comply with all of its obligations under
                           the counter-indemnity dated 16th February, 1996 in
                           favour of the Bank in respect of the Pool LC referred
                           to in paragraph (a) above and all other instruments,
                           obligations and liabilities to which that
                           counter-indemnity applies.

         (v)      the following new paragraphs 7 and 8 are inserted (and the
                  existing paragraphs 7 and 8 are renumbered accordingly):

                  "7.      PROCEEDS OF EQUITY OFFERINGS

                  The net cash proceeds of any equity offering by Independent
                  Energy Holdings PLC shall, on receipt thereof by Independent
                  Energy Holdings PLC, be utilised to either (i) subscribe and
                  pay for additional equity capital in the Company or (ii) lend
                  to the Company by way of subordinated loan on terms expressly
                  approved by the Bank in relation to the relevant loan. Upon
                  receipt of such funds by the Company, the proceeds shall:

                  (i)      firstly, be used to repay any amounts demanded by the
                           beneficiary under the Pool LC and paid by the Bank,
                           together with accrued interest thereon in accordance
                           with paragraph (iv) above;


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                  (ii)     secondly, be used to cash collateralise the Pool LC
                           up to the undrawn fact amount of the Pool LC; and

                  (iii)    thirdly, be used to repay any overdraft or other
                           letter of credit outstanding under the Ancillary
                           Facility.

                  8.       CASH COLLATERALISATION

                  The Bank may by notice to the Company at any time when an
                  Event of Default (as defined in the (pound)80,000,000 credit
                  agreement dated 8th July, 1999 to which the Company and the
                  Bank are party) is subsisting require the Company, in respect
                  of each (or any) letter or credit, to pay to the Bank for
                  crediting to such collateral account (held on such terms) as
                  the Bank may specify an amount equal to the face amount for
                  the time being of the relevant letter(s) of credit and the
                  Company shall immediately comply with such requirement, which
                  shall immediately constitute a liquidated and accrued debt due
                  and payable for the benefit of the Bank";

(b)      the Original Ancillary Facility Letter, as amended by paragraph (a)
         above, shall continue in full force and effect and this letter and the
         Original Ancillary Facility Letter shall be and construed together as a
         single document;

(c)      for the avoidance of doubt, the Original Ancillary Facility Letter as
         amended by this letter shall continue to constitute the Ancillary
         Facility Letter for the purposes of (and as defined in) the
         (pound)80,000,000 credit agreement dated 8th July, 1999 to which you
         and we (among others) are party, and accordingly all provisions of that
         credit agreement (and each of the other Finance Documents, as defined
         in it) (including, without limitation, Clauses 2.5 (Ancillary Facility)
         and 18 (Guarantee) shall continue to apply to the Original Ancillary
         Facility Letter as amended by this letter as they currently do the
         Ancillary Facility; and

(d)      this letter is governed by English law, is supplemental to the Original
         Facility Letter and is a Finance Document for the purposes of the
         credit agreement referred to in paragraph (c) above (subject only to
         its designation as such by the Agent (as defined in that credit
         agreement) to the extent (if any) such designation is required).

Yours faithfully



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For and on behalf of

BARCLAYS BANK PLC

We agree to the above:



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For and on behalf of                      Date

INDEPENDENT ENERGY UK LIMITED



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For and on behalf of                      Date

INDEPENDENT ENERGY HOLDINGS PLC