EXHIBIT 4.2


                   YORKSHIRE POWER FINANCE LIMITED, as Issuer

                                       and

                   YORKSHIRE POWER GROUP LIMITED, as Guarantor

                                       and

                              THE BANK OF NEW YORK,

                       as Trustee, Principal Paying Agent,

                          Registrar and Transfer Agent

                                       and

                       BANQUE GENERALE DU LUXEMBOURG S.A.,

                       as Paying Agent and Transfer Agent

                                  $275,000,000

                  ___% Junior Subordinated Deferrable Interest
                     Debentures, Series A due ________, 2038

                          First Supplemental Indenture

                            Dated as of May __, 1998

 
     FIRST SUPPLEMENTAL INDENTURE, dated as of May __, 1998 (this "First
Supplemental Indenture"), among YORKSHIRE POWER FINANCE LIMITED, a limited
liability company organized under the laws of the Cayman Islands, as issuer (the
"Company"), YORKSHIRE POWER GROUP LIMITED, a private limited company
incorporated under the laws of England and Wales, as guarantor (the
"Guarantor"), THE BANK OF NEW YORK, as Trustee, Principal Paying Agent,
Registrar and Transfer Agent under the Original Indenture referred to below (the
"Trustee"), and BANQUE GENERALE DU LUXEMBOURG S.A., as Paying and Transfer Agent
under the Original Indenture.

                                   WITNESSETH:

     WHEREAS, each of the Company and the Guarantor has heretofore executed and
delivered to the Trustee an indenture dated as of May __, 1998 (hereinafter
called the "Original Indenture"), to provide for the issuance from time to time
of certain of its unsecured subordinated debentures, notes or other evidences of
indebtedness (herein called the "Securities"), the form and terms of which are
to be established as set forth in Sections 2.01 and 2.05 of the Original
Indenture;

     WHEREAS, Section 9.01 of the Original Indenture provides, among other
things, that the Company, the Guarantor and the Trustee may enter into
indentures supplemental to the Original Indenture for, among other things, the
purpose of establishing the form and terms of the Securities of any series as
permitted by Sections 2.01 and 2.05 of the Original Indenture and of appointing
an Authenticating Agent with respect to the Securities of any series;

     WHEREAS, the Company desires to create a series of the Securities in an
aggregate principal amount of $275,000,000 to be designated the "___% Junior
Subordinated Deferrable Interest Debentures, Series A due ________, 2038", and
all action on the part of the Company necessary to authorize the issuance of
these Securities under the Original Indenture and this First Supplemental
Indenture has been duly taken; and

     WHEREAS, all acts and things necessary to make such Securities, when
executed by the Company and authenticated and delivered by the Trustee as in the
Original Indenture provided, the valid and binding obligations of the Company
and to constitute these presents a valid and binding supplemental indenture and
agreement according to its terms, have been done and performed;

     NOW, THEREFORE, THIS FIRST SUPPLEMENTAL INDENTURE WITNESSETH:

     That in consideration of the premises and of the acceptance and purchase of
the Series A Debentures (hereinafter defined) by the holders thereof and of the
acceptance of this trust by the Trustee, each of the Company and the Guarantor
covenants and agrees with the Trustee, for the equal benefit of holders of the
Series A Debentures, as follows:

 
                                   ARTICLE ONE

                                   DEFINITIONS

     The use of the terms and expressions herein is in accordance with the
definitions, uses and constructions contained in the Original Indenture and the
forms of Securities attached hereto as Exhibits A and B, respectively. In
addition, for all purposes of this First Supplemental Indenture, except as
otherwise expressly provided or unless the context otherwise expressly requires,
the following terms shall have the respective meanings assigned to them as
follows and shall be construed as if defined in Article One of the Original
Indenture:

     "Book-Entry Depositary" means The Bank of New York as designated by the
Company in the Deposit Agreement until a successor shall have become such
pursuant to the applicable provisions of the Deposit Agreement, and thereafter
"Book-Entry Depositary" shall mean such successor Book-Entry Depositary or its
nominee or the custodian of either.

     "Corporate Trust Office" means the principal office of the Trustee in the
City of New York, at which at any particular time its corporate trust business
shall be administered, which at the date hereof is 101 Barclay Street, New York,
New York 10286.

     "Deferred Interest" means each installment of interest not paid during any
Extension Period and interest thereon. Deferred installments of interest shall
bear interest at the rate of ____% per annum from the applicable Interest
Payment Date to the date of payment, compounded quarterly, to the extent
permitted by applicable law.

     "Definitive Registered Series A Debentures" means Series A Debentures in
the form of Exhibit B to this First Supplemental Indenture.

     "Deposit Agreement" means the Deposit Agreement, dated as of May 1, 1998,
among the Company, the Book-Entry Depositary and the holders and beneficial
owners from time to time of interests in the Book-Entry Interests issued
thereunder.

     "DTC" means The Depository Trust Company, New York, New York, or its
successors.

     "Extension Period" means any period during which the Company has elected to
defer payments of interest, which deferral may be for a period of up to twenty
(20) consecutive quarters.

     "Global Series A Debentures" means Global Bearer Securities, evidencing the
Series A Debentures issued to the Book-Entry Depositary substantially in the
form of Exhibit A to this First Supplemental Indenture.



                                       2

 
     "Series A Debenture" means the Company's ____% Junior Subordinated
Deferrable Interest Debenture, Series A due _______, 2038, as authenticated and
issued under this Indenture.

     "Stated Maturity" means, with respect to the Series A Debentures, ________,
2038.

     "Trust" means Yorkshire Capital Trust I, a statutory business trust formed
under Delaware law to issue Trust Securities, the proceeds of which will be used
to purchases the Series A Debentures.

                                   ARTICLE TWO

                  TERMS AND ISSUANCE OF THE SERIES A DEBENTURES

     SECTION 201. Issue of Securities. A series of Securities which shall be
designated the ____% Junior Subordinated Deferrable Interest Debenture, Series A
due ________, 2038 shall be executed, authenticated and delivered in accordance
with the provisions of, and shall in all respects be subject to, the terms,
conditions and covenants of the Original Indenture and this First Supplemental
Indenture (including the forms of Series A Debentures set forth in Exhibits A
and B hereto). The aggregate principal amount of the Series A Debentures which
may be authenticated and delivered under the First Supplemental Indenture shall
not, except as permitted by the provisions of the Original Indenture, exceed
$275,000,000.

     SECTION 202. Form of Series A Debentures; Incorporation of Terms. The forms
of the Global Series A Debentures and the Definitive Registered Series A
Debentures shall be substantially in the forms of Exhibits A and B,
respectively, attached hereto, the terms of which are herein incorporated by
reference and which are part of this First Supplemental Indenture.

     SECTION 203. Additional Interest. So long as any Trust Securities issued by
the Trust remain outstanding, if the Trust shall be required to pay, with
respect to any income derived from payments of principal of or interest on the
Series A Debentures or pursuant to the Guarantee, any amount for or on an
account of any taxes, duties, assessments or governmental charges of whatever
nature imposed by a Taxing Jurisdiction or any other taxing authority, then, in
any such case, the Company or the Guarantor, as the case may be, will pay
Additional Interest on such Series A Debentures.

     SECTION 204. Deferral of Interest Payments. So long as no Event of Default
has occurred and is continuing, the Company has the right to extend the interest
payment period of the Series A Debentures, at any time and from time to time,
for up to twenty (20) consecutive quarters (each, an "Extension Period"), but
not beyond the Stated Maturity. Until all deferred payments of interest together
with interest thereon have been paid in full, interest will continue to accrue,
together with interest thereon at ____%, to the extent permitted by law. Prior
to the termination of any such Extension Period, the Company may further extend
the interest payment period, provided that such



                                       3

 
Extension Period, together with all such previous and further extensions of that
Extension Period, shall not exceed twenty (20) consecutive quarters.

     Upon the termination of any Extension Period, which termination shall be on
an Interest Payment Date, the Company shall pay all Deferred Interest on the
next succeeding Interest Payment Date (in the case of a Bearer Security) to the
bearer thereof and (in the case of a Registered Security) to the Person in whose
name the Series A Debentures are registered on the Regular Record Date for such
Interest Payment Date; provided, that Deferred Interest payable at Stated
Maturity or on any Redemption Date will be paid to the Person to whom principal
is payable.

     The Company shall give the Holder or Holders of the Series A Debentures and
the Trustee notice of its selection or extension of an Extension Period at least
one Business Day prior to the earlier of (i) the next succeeding Interest
Payment Date, or (ii) the date the Company is required to give notice to the New
York Stock Exchange or other applicable self-regulatory organization or to the
Holders of the Series A Debentures of the record date or Interest Payment Date,
but, in any event, not less than one Business Day prior to such record date. The
Company shall cause the Trust to give notice of the Company's selection of such
Extension Period to Holders of the Trust Securities of the Trust. The month in
which any notice is given pursuant to the immediately preceding sentence of this
Section shall constitute the first month of the first quarter of the twenty (20)
quarters.

     At any time any of the foregoing notices are given to the Trustee, the
Company shall give to the Paying Agent for the Series A Debentures such
information as said Paying Agent shall reasonably require to order to fulfill
its tax reporting obligations with respect to such Series A Debentures.

     SECTION 205. Guarantee. The Guarantee provided by Article XV of the
Original Indenture shall be applicable to the Series A Debentures.

     SECTION 206. Place of Payment. The Place of Payment in respect of the
Series A Debentures will be in The City of New York, initially the Corporate
Trust Office of The Bank of New York, and, for so long as the Series A
Debentures are listed on the Luxembourg Stock Exchange, in Luxembourg, initially
the corporate trust office of Banque Generale du Luxembourg S.A., which at the
date hereof, is located at 50 Avenue J. F. Kennedy, L-2951 Luxembourg.

     SECTION 207. Issuance of Global Series A Debentures. The Series A
Debentures shall be issued as one or more Global Series A Debentures and
delivered by the Trustee to the Book-Entry Depositary, as the Holder thereof, or
a nominee or custodian therefor, to be held by the Book-Entry Depositary
pursuant to the Deposit Agreement. Definitive Registered Series A Debentures
shall only be issued by the Company in exchange for the Global Series A
Debentures in the circumstances set forth in the Global Series A Debentures.



                                       4

 
     SECTION 208. Denominations. The Series A Debentures may be issued in the
denominations of $25, or any integral multiple thereof.

     SECTION 209. Regular Record Date for the Series A Debentures. The Regular
Record Date for the Series A Debentures shall be 15 calendar days immediately
prior to each Interest Payment Date.

     SECTION 210. Redemption. The Series A Debentures shall be subject to
redemption at the option of the Company, in whole or in part, without premium or
penalty, at any time or from time to time on or after _______, 2003, at a
Redemption Price equal to 100% of the principal amount to be redeemed plus
accrued but unpaid interest, including Additional Interest, if any, to the
Redemption Date; provided, however, that if a redemption in part shall result in
the delisting of the Trust Securities issued by the Trust, the Company may only
redeem the Series A Debentures in whole. In addition, upon the occurrence of a
Special Event at any time, the Company may, within ninety (90) days following
the occurrence thereof and subject to the terms and conditions of the Indenture,
elect to redeem the Series A Debentures, in whole, at a price equal to 100% of
the principal amount to be redeemed plus any accrued but unpaid interest
(including Additional Interest) to the Redemption Date.

     The Company shall not redeem less than all of the Series A Debentures
unless all accrued and unpaid interest, if any, has been paid in full on all
Outstanding Series A Debentures for all interest periods terminating on or prior
to the Redemption Date.

     In the event of redemption of the Series A Debentures in part only, a new
Series A Debenture or Debentures for the unredeemed portion will be issued in
the name or names of the Holders thereof upon the surrender thereof.

     The Series A Debentures will not have a sinking fund.

     Notice of redemption shall be given as provided in Section 13.03 of the
Original Indenture.

     Any redemption of less than all of the Series A Debentures shall, with
respect to the principal thereof, be divisible by $25.

     SECTION 211. Listing of Series A Debentures. If the Trust is liquidated
pursuant to the Trust Agreement and the Series A Debentures remain Outstanding,
the Company will use its best efforts to list the Series A Debentures on the New
York Stock Exchange or any other such exchange on which the Trust Securities
relating to the Trust are then listed and traded.



                                       5

 
                                  ARTICLE THREE

                   AUTHENTICATING AGENT; BOOK-ENTRY DEPOSITARY

     SECTION 301. Authenticating Agent; Book-Entry Depositary. The Bank of New
York, a New York banking corporation, and its successors are hereby appointed
Authenticating Agent and Book-Entry Depositary with respect to the Series A
Debentures.

                                  ARTICLE FOUR

                                  MISCELLANEOUS

     SECTION 401. Execution of Supplemental Indenture. This First Supplemental
Indenture is executed and shall be construed as an indenture supplemental to the
Original Indenture and, as provided in the Original Indenture, this First
Supplemental Indenture forms a part thereof.

     SECTION 402. Conflict with Trust Indenture Act. If any provision hereof
limits, qualifies or conflicts with another provision hereof which is required
to be included in this First Supplemental Indenture by any of the provisions of
the Trust Indenture Act, such required provision shall control.

     SECTION 403. Effect of Headings. The Article and Section headings herein
are for convenience only and shall not affect the construction hereof.

     SECTION 404. Successors and Assigns. All covenants and agreements in this
First Supplemental Indenture by each of the Company or the Guarantor shall bind
its successors and assigns, whether so expressed or not.

     SECTION 405. Separability Clause. In case any provision in this First
Supplemental Indenture or in the Series A Debentures shall be invalid, illegal
or unenforceable, the validity, legality and enforceability of the remaining
provisions shall not in any way be affected or impaired thereby.

     SECTION 406. Benefits of First Supplemental Indenture. Nothing in this
First Supplemental Indenture or in the Series A Debentures, express or implied,
shall give to any person, other than the parties hereto and their successors
hereunder and the Holders, any benefit or any legal or equitable right, remedy
or claim under this First Supplemental Indenture.

     SECTION 407. Execution and Counterparts. This First Supplemental Indenture
may be executed in any number of counterparts, each of which shall be deemed to
be an original, but all such counterparts shall together constitute but one and
the same instrument.


                                       6

 
     IN WITNESS WHEREOF, the parties hereof have caused this First Supplemental
Indenture to be duly executed by their respective officers, directors or
signatories duly authorized thereto, all as of the day and year first above
written.

                                    YORKSHIRE POWER FINANCE 
                                    LIMITED


                                    By
                                      ------------------------------------------
                                       Title:


                                    YORKSHIRE POWER GROUP LIMITED

                                    By
                                      ------------------------------------------
                                       Title:


                                    THE BANK OF NEW YORK,
                                    as Trustee, Principal Paying Agent, Security
                                    Registrar and Transfer Agent


                                    By
                                      ------------------------------------------
                                       Title:


                                    BANQUE GENERALE DU 
                                    LUXEMBOURG S.A., as Paying Agent
                                    and Transfer Agent


                                    By
                                      ------------------------------------------
                                       Title:


                                       7

 
                                                                       EXHIBIT A

                   {FORM OF FACE OF GLOBAL SERIES A DEBENTURE}

     THE INDEBTEDNESS EVIDENCED BY THIS SECURITY IS, TO THE EXTENT PROVIDED IN
THE INDENTURE, SUBORDINATE AND SUBJECT IN RIGHT OF PAYMENT TO THE PRIOR PAYMENT
IN FULL OF ALL SENIOR DEBT OF THE COMPANY AND THIS SECURITY IS ISSUED SUBJECT TO
THE PROVISIONS OF THE INDENTURE WITH RESPECT THERETO.

     THIS SECURITY IS A GLOBAL BEARER SECURITY WITHIN THE MEANING OF THE
INDENTURE HEREINAFTER REFERRED TO AND IS HELD BY A BOOK-ENTRY DEPOSITARY. THIS
SECURITY IS EXCHANGEABLE FOR SECURITIES HELD BY A PERSON OTHER THAN THE
BOOK-ENTRY DEPOSITARY OR ITS NOMINEE ONLY IN THE LIMITED CIRCUMSTANCES DESCRIBED
IN THE INDENTURE.

     UNLESS THIS GLOBAL BEARER SECURITY IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF THE BOOK-ENTRY DEPOSITARY TO THE COMPANY OR ITS AGENT FOR
EXCHANGE OR PAYMENT, AND ANY DEFINITIVE REGISTERED SECURITY IS ISSUED IN THE
NAME OR NAMES AS DIRECTED IN WRITING BY THE BOOK-ENTRY DEPOSITARY, ANY TRANSFER,
PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS
WRONGFUL INASMUCH AS THE BEARER HEREOF, THE BOOK-ENTRY DEPOSITARY, HAS AN
INTEREST HEREIN.

                         YORKSHIRE POWER FINANCE LIMITED

____% Junior Subordinated Deferrable Interest Debenture, Series A due ______,
2038

No. ___________                                               $_________________
                                                              CUSIP No.:________


     YORKSHIRE POWER FINANCE LIMITED, a limited liability company incorporated
under the laws of the Cayman Islands (herein called the "Company", which term
includes any successor corporation under the Indenture hereinafter referred to),
for value received, hereby promises to pay to the bearer upon surrender hereof,
the principal sum of __________ Dollars on ________________, and to pay interest
thereon from _____________, or from the most recent Interest Payment Date to
which interest has been paid or duly provided for, quarterly on ____________,
____________, ____________ and ____________ in each year, commencing
________________, 199__, at the rate per annum provided in the title hereof,
until the principal hereto is paid or made available for payment. The interest
so payable, and punctually paid or duly provided for, on any Interest Payment
Date will, as provided in such Indenture, be paid to the bearer on such Interest
Payment Date. So long as an Extension Period is not


                                      A-1

 
occurring, any such interest not so punctually paid or duly provided for will
forthwith cease to be payable to the bearer on such Interest Payment Date and
may be paid to the bearer hereof at the time of payment of such Defaulted
Interest or be paid at any time in any other lawful manner not inconsistent with
the requirements of any securities exchange on which the Securities of this
series may be listed, and upon such notice as may be required by such exchange,
all as more fully provided in said Indenture.

     All payments in respect of this Security and all payments made pursuant to
the Guarantee of this Security shall be made in immediately available funds at
or through the office or agency of the Company maintained for that purpose in
the Borough of Manhattan, The City of New York, and, for so long as this
Security shall be listed on the Luxembourg Stock Exchange, in Luxembourg, in
such coin or currency of the United States of America as at the time of payment
is legal tender for the payment of public and private debt.

     So long as no Event of Default has occurred and is continuing, the Company
shall have the right at any time and from time to time during the term of this
Security to extend the interest payment period of such Security for up to 20
consecutive quarters but not beyond the Stated Maturity of this Security (each,
an "Extension Period"), during which periods unpaid interest (together with
interest thereon) will compound quarterly at the interest rate on this Security
("Deferred Interest"). Upon the termination of each Extension Period, which
shall be an Interest Payment Date, the Company shall pay all Deferred Interest
on the next succeeding Interest Payment Date to the bearer thereof, as provided
in the Indenture, provided that any Deferred Interest payable at Stated Maturity
or on any Redemption Date will be paid to the Person to whom principal is
payable. Prior to the termination of any such Extension Period, the Company may
extend the interest payment period, provided that such Extension Period together
with all such previous and further extensions thereof shall not exceed 20
consecutive quarters. Upon the termination of any such Extension Period, and the
payment of all accrued and unpaid interest and any Additional Interest then due,
the Company may select a new Extension Period, subject to the above
requirements. If the Company shall have given notice of its election to select
any Extension Period, neither the Company nor the Guarantor referred to herein
shall, directly or indirectly, (i) declare or pay any cash dividends or
distributions on, or redeem, purchase, acquire, or make a liquidation payment
with respect to, any of its capital stock (which includes common and preferred
stock) or (ii) make any payment of principal of, or interest or premium, if any,
on or repay or repurchase or redeem any of its debt securities (including any
other Securities) that rank pari passu with or junior in interest to the
Securities or the Guarantee, respectively, or (iii) make any payments with
respect to any guarantee that ranks pari passu with or junior in interest to the
Securities or the Guarantee, respectively, or (iv) make any payment of principal
or premium, if any, or interest on, or repay, repurchase or redeem any of its
debt securities held by, make any loans or advances to, or make any payments
with respect to any guarantee of the debt of, any affiliate, in each case other
than (a) dividends or distributions in shares of, or options, warrants or rights
to subscribe for or purchase shares of, common stock of the Company or the
Guarantor and exchanges or conversions of common stock of one class for common
stock of another class; (b) payments by the Guarantor under the Trust Securities
Guarantee (or any other



                                      A-2

 
guarantee by the Guarantor with respect to any securities of any of its direct
or indirect subsidiaries, provided that the proceeds from the issuance of such
securities were used to purchase other Securities; (c) payments by the Guarantor
under the Guarantee; (d) any dividend or payment by the Guarantor which is
applied, directly or indirectly, to the payment of any Tax Payments (e) payments
by the Guarantor, directly or indirectly, on the Intercompany Notes or any other
promissory notes held by the Company (or any other direct or indirect
wholly-owned subsidiary of the Guarantor) evidencing loans made with the
proceeds from the issuance by the Company) (or any other direct or indirect
wholly-owned subsidiary of the Guarantors) of securities guaranteed by the
Guarantor or (f) the reinvestment of any proceeds received under clause (e)
above by the Company (or any other direct or indirect wholly-owned subsidiary of
the Guarantor) in additional debt securities of the Guarantor or any of its
other direct or indirect wholly-owned subsidiaries. The Company shall give the
Holder of this Security and the Trustee notice of its selection or extension of
an Extension Period at least one Business Day prior to the earlier of (i) the
next succeeding Interest Payment Date or (ii) the date the Company is required
to give notice to the New York Stock Exchange or other applicable
self-regulatory organization or to the Holders of this Security of the record
date or Interest Payment Date, but, in any event, not less than one Business Day
prior to such record date.

     The indebtedness evidenced by this Security is, to the extent provided in
the Indenture, subordinate and subject in right of payment to the prior payment
in full of all Senior Debt (as defined in the Indenture) of the Company, and
this security is issued subject to the provisions of the Indenture with respect
thereto. Each Holder of this security, by accepting the same, (a) agrees to and
shall be bound by such provisions, (b) authorizes and directs the Trustee on his
behalf to take such action as may be necessary or appropriate to effectuate the
subordination so provided, and (c) appoints the Trustee his attorney-in-fact for
any and all such purposes. Each Holder hereof, by his acceptance thereof, waives
all notice of the acceptance of the subordination provisions contained herein
and in the Indenture by each holder of Senior Debt of the Company, whether now
outstanding or hereafter incurred, and waives reliance by each such holder upon
said provisions.

     All payments of principal of, and premium, if any, and interest in respect
of this Security and all payments made pursuant to the Guarantee of this
Security shall be made free and clear of, and without withholding or deduction
for or on account of any present or future taxes, duties, assessments or
governmental charges of whatever nature imposed, levied, collected, withheld or
assessed by or within a Taxing Jurisdiction or by or within any political
subdivision thereof or any authority therein or thereof having power to tax
("Gross-Up Taxes"), unless such withholding or deduction is required by law. In
the event of any such withholding or deduction, the Company or the Guarantor, as
the case may be, shall pay to the Holder such additional amounts that would
otherwise have been due to such Holder in the absence of such withholding or
deduction ("Additional Amounts") except that no such Additional Amounts shall be
payable:

          (a) to, or to a Person on behalf of, a Holder who is liable for such
     Gross-Up Taxes in respect of this Security or the Guarantee of this
     Security by reason of such Holder or beneficial owner having some
     connection with the relevant Taxing



                                      A-3

 
     Jurisdiction (including being a citizen or resident or national of, or
     carrying on a business or maintaining a permanent establishment in, or
     being physically present in, such Taxing Jurisdiction) other than the mere
     holding of this Security or the receipt of principal of, and premium, if
     any and interest in respect thereof or in respect of the Guarantee of this
     Security;

          (b) to, or to a Person on behalf of, a Holder who presents this
     Security (where presentation is required) for payment more than 30 days
     after the Relevant Date except to the extent that the Holder would have
     been entitled to such Additional Amounts on presenting this Security for
     payment on the last day of such period of 30 days;

          (c) to, or to a Person on behalf of, a Holder who presents this
     Security (where presentation is required) in the United Kingdom or Cayman
     Islands;

          (d) to, or to a Person on behalf of, a Holder who would not be liable
     or subject to the withholding or deduction by making a declaration of
     nonresidence or similar claim for exemption to the relevant tax authority;
     or

          (e) to, or to a Person on behalf of, a Holder of a Registered Security
     that is not a Global Security issued pursuant to the request of owners of
     interests representing a majority in Outstanding principal amount of such
     Securities following and during the continuance of an Event of Default if
     such Holder (or any predecessor Holder) was one of such owners requesting
     that such Registered Securities be so issued.

     Such Additional Amounts will also not be payable where, had the beneficial
owner of the Security (or any interest therein) been the Holder of the Security,
he would not have been entitled to payment of Additional Amounts by reason of
any one or more of clauses (a) through (e) above. If the Company or the
Guarantor, as applicable, shall determine that Additional Amounts will not be
payable because of the immediately preceding sentence, the Company or the
Guarantor, as applicable, will inform such Holder promptly after making such
determination setting forth the reason(s) therefor.

     "Relevant Date" means whichever is the later of (i) the date on which such
payment first becomes due and (ii) if the full amount payable has not been
received in The City of New York by the Book-Entry Depositary of the Trustee on
or prior to such due date, the date on which, the full amount having been so
received, notice to that effect shall have been given to the bearer hereof in
accordance with the Indenture.

     References to principal of, and premium or interest in respect of, this
Security or any payments pursuant to the Guarantee of this Security shall be
deemed to include any Additional Amounts which may be payable as set forth in
the Indenture or in this Security.

     The Company shall furnish to the Trustee the official receipts (or a
certified copy of the official receipts) evidencing payment of the Gross-Up
Taxes.



                                      A-4

 
Copies of such receipts shall be made available to the Holder of this Security
upon request.

     So long as the Securities of this series are listed on the Luxembourg Stock
Exchange and the rules of the Luxembourg Stock Exchange so require, notices to
Holders of Securities of this series will be published in a leading newspaper
having general circulation in Luxembourg (which is expected to be the
Luxemburger Wort).

     REFERENCE IS HEREBY MADE TO THE FURTHER PROVISIONS OF THIS SECURITY SET
FORTH ON THE REVERSE HEREOF, WHICH FURTHER PROVISIONS SHALL FOR ALL PURPOSES
HAVE THE SAME EFFECT AS IF SET FORTH AT THIS PLACE.

     Unless the certificate of authentication hereon has been executed by the
Trustee referred to on the reverse hereof by manual signature, this Security
shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.



                                      A-5

 
     IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed by an authorized signatory of the Company.


                                          YORKSHIRE POWER FINANCE
                                          LIMITED


                                          By:
                                             -----------------------------------
                                             Authorized Signatory

                          CERTIFICATE OF AUTHENTICATION

     This is one of the Securities of the series designated herein and referred
to in the within-mentioned Indenture.

THE BANK OF NEW YORK,
                                          as Trustee


                                          By:
                                             -----------------------------------
                                             Authorized Signatory

Dated:



                                      A-6

 
                          [Form of Reverse of Security]

                         YORKSHIRE POWER FINANCE LIMITED
        ___% Junior Subordinated Deferrable Interest Debenture, Series A
                             due ____________, 2038

     This Security is one of a duly authorized issue of securities of the
Company (herein called the "Securities"), issued and to be issued in one or more
series under an Indenture, dated as of May 1, 1998 (herein called the "Original
Indenture"), among the Company, Yorkshire Power Group Limited, as guarantor (the
"Guarantor"), The Bank of New York, as trustee, principal paying agent,
registrar and transfer agent (herein called the "Trustee", which term includes
any successor trustee under the Indenture), and Banque Generale du Luxembourg
S.A., as paying and transfer agent (the "Paying and Transfer Agent"), as
supplemented by the First Supplemental Indenture, dated as of May __, 1998
(together with the Original Indenture and any other supplements thereto, the
"Indenture"), among the Company, the Guarantor, the Trustee and the Paying and
Transfer Agent to which Indenture and all indentures supplemental thereto
reference is hereby made for a statement of the respective rights, limitations
of rights, duties and immunities thereunder of the Company, the Guarantor, the
Trustee, the Paying and Transfer Agent and the Holders of the Securities and of
the terms upon which the Securities are, and are to be, authenticated and
delivered. This Security is one of the series designated on the face hereof,
limited in aggregate principal amount to $275,000,000.

     The Company shall have the right, subject to the terms and conditions of
the Indenture, to redeem this Security at any time on or after ___________,
2003, at the option of the Company, without premium or penalty, in whole or in
part, at a Redemption Price equal to 100% of the principal amount to be redeemed
plus any accrued and unpaid interest, including Additional Interest, if any, to
the Redemption Date. Upon the occurrence of a Special Event (as defined below)
at any time, the Company may, within 90 days following the occurrence thereof
and subject to the terms and conditions of the Indenture, redeem this Security
without premium or penalty, in whole, at a Redemption Price equal to 100% of the
principal amount thereof plus any accrued and unpaid interest, including
Additional Interest, if any, to the Redemption Date. A Special Event may be a
Tax Event or an Investment Company Act Event.

"Tax Event" means the receipt by the Guarantor or the Company of an opinion of
independent counsel (which may be counsel to the Guarantor or its affiliates)
experienced in such matters to the effect that there has been (a) any amendment
to, or change (including any announced prospective change) in, the laws or any
regulations thereunder) of any supra national federation to which the United
Kingdom belongs or the jurisdiction (or any political subdivision or taxing
authority thereof or therein) in which the Company or the Guarantor is
incorporated or created, as applicable, or in which the Company or the Guarantor
is managed or has a place of business (each, a "Taxing Jurisdiction"), (b) any
official administrative pronouncement or judicial decision interpreting,
clarifying or applying such laws or regulations or (c) a threatened challenge
asserted by a government or taxing authority with respect to the Guarantor or
any of its



                                      A-7

 
subsidiaries, or a threatened challenge asserted in writing by a government or
taxing authority against any other taxpayer that has raised capital through the
issuance of securities that are substantially similar to the Securities or the
Trust Securities, which amendment or change is effective or which pronouncement
clarification, challenge or decision is announced on or after May __, 1998, and
that results in their being more than an insubstantial risk that (i) the Company
is, or will be within 90 days of the date thereof , subject to income tax within
a Taxing Jurisdiction (other than the United Kingdom corporation income tax)
with respect to interest received or accrued on the Intercompany Notes, (ii) the
Company is, or will be within 90 days of the date thereof, subject to more than
a de minimis amount of other tax, duties or other governmental charges, (iii)
interest payable by the Company on the Securities is not, or within 90 days of
the date thereof will not be, deductible, in whole or in part for United States
Federal income tax or United Kingdom corporation income tax purposes, as they
accrue by the Company or by a member of any tax group to which the Guarantor
belongs or (iv) interest payable with respect to the Intercompany Notes by the
Guarantor or its affiliates is not, or within 90 days of the date thereof will
not be, deductible, in whole or in part, for (as appropriate) United States
Federal or United Kingdom corporation income tax purposes, by one of (as
appropriate) the Guarantor, its shareholders or a member of any tax group to
which the Guarantor belongs. "Investment Company Act Event" shall mean that the
Guarantor or the Company shall have received an opinion of independent counsel
(which may be counsel to the Guarantor or its affiliates) experienced in such
matters to the effect that, as a result of the occurrence of a change in law or
regulation or a change in interpretation or application of law or regulation by
any legislative body, court, governmental agency or regulatory authority (an
"Investment Company Act Change"), there is more than an insubstantial risk that
the Guarantor or the Company is or will be considered an "investment company"
that is required to be registered under the Investment Company Act of 1940, as
amended, which Investment Company Act Change becomes effective on or after May
__, 1998.

     Notice of redemption shall be given as provided in the Indenture not less
than 30 days nor more than 60 days prior to the date fixed for redemption.

     If fewer than all the Securities of this series are to be redeemed,
selection of Securities of this series for redemption will be made by the
Trustee in any manner the Trustee deems fair and appropriate and that complies
with applicable legal and securities exchange requirements.

     Unless the Company defaults in payment of the redemption price, from and
after the redemption date, the Securities of this series or portions thereof
called for redemption will cease to bear interest, and the Holders thereof will
have no right in respect to such Securities of this series except the right to
receive the redemption price thereof.

     In the event of redemption of this Security in part only, a new Security of
this series and of like tenor for the unredeemed portion hereof will be issued
to the Holder hereof upon the cancellation hereof.



                                      A-8

 
     If an Event of Default with respect to Securities of this series shall
occur and be continuing, the principal of the Securities of this series may be
declared due and payable in the manner and with the effect provided in the
Indenture. At any time after such declaration of acceleration with respect to
Securities of any series has been made, but before a judgment or decree for
payment of money has been obtained by the Trustee as provided in the Indenture,
if all Events of Default with respect to Securities of this series have been
cured or waived (other than the non-payment of principal of the Securities which
has become due solely by reason of such declaration of acceleration) then such
declaration of acceleration and its consequences shall be automatically annulled
and rescinded.

     The Securities of this Series are subject to redemption in whole but not in
part upon not less than 30 nor more than 60 days' notice given as provided in
the Indenture, at a price equal to the outstanding principal amount thereof,
together with Additional Amounts, if any, and accrued and unpaid interest, if
any, to the Redemption Date if, (a) the Company or the Guarantor satisfies the
Trustee prior to the giving of such notice that it has or will become obligated
to pay Additional Amounts with respect to the Securities or the Guarantee as a
result of either (i) any change in, or amendment to, the laws or regulations of
a Taxing Jurisdiction or any political subdivision or any authority or agency
thereof or therein having power to tax or levy duties, or any change in the
application or interpretation of such laws or regulations, which change or
amendment becomes effective on or after May __, 1998 or (ii) the issuance of
Definitive Registered Series A Debentures Securities pursuant to any of clauses
(a), (b) or (d) of the third following paragraph and (b) such obligation cannot
be avoided by the Company or the Guarantor taking reasonable measures available
to it, subject, as provided in the Indenture, to the delivery by the Company or
the Guarantor of an Officers' Certificate stating that such obligation to pay
Additional Amounts cannot be avoided by the Company or the Guarantor taking
reasonable measures available to it.

     The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the Indenture or any supplemental
indenture or the rights and obligations of the Company and the rights of the
Holders of the Securities of each series to be affected under the Indenture at
any time by the Company and the Trustee with the consent of the Holders of a
majority in aggregate principal amount of the Securities at the time Outstanding
of all series to be affected (voting as a class). The Indenture also contains
provisions permitting the Holders of specified percentages in principal amount
of the Securities of each series at the time Outstanding, on behalf of the
Holders of all Securities of such series, to waive compliance by the Company
with certain provisions of the Indenture and certain past defaults under the
Indenture and their consequences. Any such consent or waiver by the Holder of
this Security shall be conclusive and binding upon such Holder and upon all
future Holders of this Security and of any Security issued upon the registration
of transfer hereof or in exchange herefor or in lieu hereof, whether or not
notation of such consent or waiver is made upon this Security.

     No reference herein to the Indenture and no provision of this Security or
of the Indenture shall alter or impair the obligation of the Company, which is
absolute



                                      A-9

 
and unconditional, to pay the principal of, and premium, if any and interest, if
any, on this Security and all payments made pursuant to the Guarantee of this
Security at the times, place and rate, and in the coin or currency, herein
prescribed.

     This Security shall be exchangeable, in whole or, in the case of clause (d)
below, in part as provided in the Indenture, for Definitive Registered Series A
Debentures registered in the names of Persons other than the Book-Entry
Depositary with respect to such series or its nominee only as provided in this
paragraph. This Security shall be so exchangeable if (a) DTC notifies the
Company and the Book-Entry Depositary that it is unwilling or unable to continue
to hold the Book-Entry Interests or at any time ceases to be a "clearing agency"
registered as such under the Exchange Act and, in either case, a successor is
not appointed by the Company within 120 days, (b) the Book-Entry Depositary for
the Securities of this series notifies the Company that it is unwilling or
unable to continue as Book-Entry Depositary with respect to this Security and no
successor is appointed within 120 days, (c) the Company executes and delivers to
the Trustee an Officers' Certificate providing that this Security shall be so
exchangeable, or (d) there shall have occurred and be continuing an Event of
Default with respect to the Securities of this series and the Holder, in such
circumstance, shall have requested in writing that this Security be exchanged
for one or more Definitive Registered Series A Debentures. Securities so issued
in exchange for this Security shall be of the same series, having the same
interest rate, if any, and maturity and having the same terms as this Security,
in authorized denominations and in the aggregate having the same principal
amount as this security and registered in such names as the Book-Entry
Depositary for this Security shall direct.

     The bearer of this Security shall be treated as the owner of it for all
purposes, subject to the terms of the Indenture. As provided in the Indenture
and subject to certain limitations therein set forth, Securities of this series
are exchangeable for a like aggregate principal amount of Securities of this
series and of like tenor of a different authorized denomination, as requested by
the Holder surrendering the same.

     No service charge shall be made for any such exchange, but the Company may
require payment of a sum sufficient to cover any tax or other governmental
charge payable in connection therewith.

     When a successor assumes all the obligations of its predecessor under the
Securities of this series and the Indenture in accordance with the terms of the
Indenture, the predecessor will be released from those obligations.

     The Trustee under the Indenture, in its individual or any other capacity,
may become the owner or pledge of Securities of this series and may otherwise
deal with the Company, the Guarantor or their respective Affiliates as if it
were not the Trustee.

     No stockholder, director, officer, employee, incorporator or Affiliate of
the Company or the Guarantor under the Securities of this series or the
Indenture or for any claim based on, in respect of or by reason of, such
obligations of their creation. Each Holder of the Securities of this series by
accepting Securities this series waives and



                                      A-10

 
releases all such liability. The waiver and release are part of the
consideration for the issuance of the Securities of this series.

     This Security shall not be valid until the Trustee or authenticating agent
signs the certificate of authentication on this Security.

     Pursuant to a recommendation promulgated by the Committee on Uniform
Security Identification Procedures, the Company will cause CUSIP numbers to be
printed on the Securities of this series as a convenience to the Holders of the
Securities of this series. No representation is made as to the accuracy of such
numbers as printed on the Securities of this series and reliance may be placed
only on the other identification numbers printed hereon.

     This Security shall be governed by and construed in accordance with the
laws of the State of New York.

     All terms used in this Security which are defined in the Indenture shall
have the meanings assigned to them in the Indenture.

                                    GUARANTEE

     FOR VALUE RECEIVED, YORKSHIRE POWER GROUP LIMITED, a private limited
company duly incorporated and existing under the laws of England and Wales (the
"Guarantor", which term includes any successor Person under the Indenture
referred to in the Security on which this notation is endorsed), hereby fully
and unconditionally guarantees to the Holder of the accompanying Security issued
by Yorkshire Power Finance Limited (the "Company"), pursuant to the terms of the
Guarantee contained in Article XV of the Indenture, the due and punctual payment
of the principal of, and premium, if any, and interest in respect of this
Security (and any Additional Amounts payable in respect thereof), when and as
the same shall become due and payable, whether at Stated Maturity, by
declaration of acceleration, call for redemption or otherwise, in accordance
with the terms of this Security and the Indenture. In case of the failure of the
Company punctually to pay any such principal, premium, if any, or interest, the
Guarantor hereby agrees to cause any such payment to be made punctually when and
as the same shall become due and payable as if such payment were made by the
Company.

     The obligations of the Guarantor to the Holders of the Securities and to
the Trustee pursuant to the Guarantee and the Indenture are expressly set forth
in Article XV of the Indenture, and reference is hereby made to such Article and
Indenture for the precise terms of the Guarantee.

     THIS GUARANTEE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE
LAWS OF THE STATE OF NEW YORK.

     The Guarantee shall not be valid or obligatory for any purpose until the
certificate of authentication on the Security upon which this notation of the
Guarantee is



                                      A-11

 
endorsed shall have been executed by the Trustee under the Indenture by the
manual signature of one of its authorized officers.

                                      YORKSHIRE POWER GROUP LIMITED

                                      By:_______________________________________
                                         Authorized Signatory


                                      A-12

 
                                                                       EXHIBIT B

           [FORM OF FACE OF DEFINITIVE REGISTERED SERIES A DEBENTURE]

THE INDEBTEDNESS EVIDENCED BY THIS SECURITY IS, TO THE EXTENT PROVIDED IN THE
INDENTURE, SUBORDINATE AND SUBJECT IN RIGHT OF PAYMENT TO THE PRIOR PAYMENT IN
FULL OF ALL SENIOR DEBT OF THE COMPANY AND THIS SECURITY IS ISSUED SUBJECT TO
THE PROVISIONS OF THE INDENTURE WITH RESPECT THERETO.

                         YORKSHIRE POWER FINANCE LIMITED
    ___% Junior Subordinated Deferrable Interest Debenture due _______, 2038

No. _______________                                         $___________________
                                                            CUSIP No.:__________

     YORKSHIRE POWER FINANCE LIMITED, a limited liability company incorporated
under the laws of the Cayman Islands (herein called the "Company", which term
includes any successor corporation under the Indenture hereinafter referred to),
for value received, hereby promises to pay to [name of registered owner], or its
registered assigns, the principal sum of _______________ Dollars on
_______________________, and to pay interest thereon from ____________________,
or from the most recent Interest Payment Date to which interest has been paid or
duly provided for, quarterly on __________, __________, __________ and
_____________ in each year, commencing _______________, 199_, at the rate per
annum provided in the title hereof, until the principal hereof is paid or made
available for payment. The interest so payable, and punctually paid or duly
provided for, on any Interest Payment Date will, as provided in such Indenture,
be paid to the Person in whose name this Security (or one or more Predecessor
Securities) is registered at the close of business on the Regular Record Date
for such interest, which shall be the fifteenth day (whether or not a Business
Day) immediately preceding such Interest Payment Date. So long as an Extension
Period is not occurring, any such interest not so punctually paid or duly
provided for will forthwith cease to be payable to the Person in whose name this
Security (or one or more Predecessor Securities) is registered on such Regular
Record Date and may be paid to the Person in whose name this Security (or one or
more Predecessor Securities) is registered at the close of business on a Special
Record Date for the payment of such Defaulted Interest to be fixed by the
Trustee, notice whereof shall be given to Holders of Securities of this series
not less than 10 days prior to such Special Record Date, or be paid at any time
in any other lawful manner not inconsistent with the requirements of any
securities exchange on which the Securities of this series may be listed, and
upon such notice as may be required by such exchange, all as more fully provided
in said Indenture.

     All payments in respect of this Security and all payments made pursuant to
the Guarantee of this Security shall be made in immediately available funds at
or through the office or agency of the Company maintained for that purpose in
the Borough of Manhattan, The City of New York, and for so long as this Security
shall be listed on the Luxembourg Stock Exchange, in Luxembourg, in such coin or
currency of the United



                                      B-1

 
States of America as at the time of payment is legal tender for the payment of
public and private debt; provided, however, that at the option of the Company,
payment of interest may be made by check mailed to the address of the Person
entitled thereto as such address shall appear in the Security Register.

     So long as no Event of Default has occurred and is continuing, the Company
shall have the right at any time and from time to time during the term of this
Security to extend the interest payment period of such Security for up to 20
consecutive quarters but not beyond the Stated Maturity of this Security (each,
an "Extension Period"), during which periods unpaid interest (together with
interest thereon) will compound quarterly at the interest rate on this Security
("Deferred Interest"). Upon the termination of each Extension Period, which
shall be an Interest Payment Date, the Company shall pay all Deferred Interest
on the next succeeding Interest Payment Date to the Person in whose name this
Security is registered at the close of business on the Regular Record Date for
such Interest Payment Date, provided that any Deferred Interest payable at
Stated Maturity or on any Redemption Date will be paid to the Person to whom
principal is payable. Prior to the termination of any such Extension Period, the
Company may extend the interest payment period, provided that such Extension
Period together with all such previous and further extensions thereof shall not
exceed 20 consecutive quarters. Upon the termination of any such Extension
Period, and the payment of all accrued and unpaid interest and any Additional
Interest then due, the Company may select a new Extension Period, subject to the
above requirements. If the Company shall have given notice of its election to
select any Extension Period, neither the Company nor the Guarantor referred to
herein shall, directly or indirectly, (i) declare or pay any cash dividends or
distributions on, or redeem, purchase, acquire, or make a liquidation payment
with respect to, any of its capital stock (which includes common and preferred
stock) or (ii) make any payment of principal of, or interest or premium, if any,
on or repay or repurchase or redeem any of its debt securities (including any
other Securities) that rank pari passu with or junior in interest to the
Securities or the Guarantee, respectively, or (iii) make any payments with
respect to any guarantee that ranks pari passu with or junior in interest to the
Securities or the Guarantee, respectively, or (iv) make any payment of principal
or premium, if any, or interest on, or repay, repurchase or redeem any of its
debt securities held by, make any loans or advances to, or make any payments
with respect to any guarantee of the debt of, any affiliate, in each case other
than (a) dividends or distributions in shares of, or options, warrants or rights
to subscribe for or purchase shares of, common stock of the Company or the
Guarantor and exchanges or conversions of common stock of one class for common
stock of another class; (b) payments by the Guarantor under the Trust Securities
Guarantee (or any other guarantee by the Guarantor with respect to any
securities of any of its direct or indirect subsidiaries, provided that the
proceeds from the issuance of such securities were used to purchase other
Securities); (c) payments by the Guarantor under the Guarantee; (d) any dividend
or payment by the Guarantor which is applied, directly or indirectly, to the
payment of any Tax Payments (e) payments by the Guarantor, directly or
indirectly, on the Intercompany Notes or any other promissory notes held by the
Company (or any other direct or indirect wholly-owned subsidiary of the
Guarantor) evidencing loans made with the proceeds from the issuance by the
Company (or any other direct or indirect wholly-owned subsidiary of the
Guarantors) of securities guaranteed by the Guarantor or



                                      B-2

 
(f) the reinvestment of any proceeds received under clause (e) above by the
Company (or any other direct or indirect wholly-owned subsidiary of the
Guarantor) in additional debt securities of the Guarantor or any of its other
direct or indirect wholly-owned subsidiaries. The Company shall give the Holder
of this Security and the Trustee notice of its selection or extension of an
Extension Period at least one Business Day prior to the earlier of (i) the next
succeeding Interest Payment Date or (ii) the date the Company is required to
give notice to the New York Stock Exchange or other applicable self-regulatory
organization or to the Holders of this Security of the record date or Interest
Payment Date, but, in any event, not less than one Business Day prior to such
record date.

     All payments of principal of, premium, if any, and interest in respect of
this Security and all payments made pursuant to the Guarantee of this Security
shall be made free and clear of, and without withholding or deduction for or on
account of any present or future taxes, duties, assessments or governmental
charges of whatever nature imposed, levied, collected, withheld or assessed by
or within a Taxing Jurisdiction or by or within any political subdivision
thereof or any authority therein or thereof having power to tax ("Gross-Up
Taxes"), unless such withholding or deduction is required by law. In the event
of any such withholding or deduction, the Company or the Guarantor, as the case
may be, shall pay to the Holder such additional amounts that would otherwise
have been due to such Holder in the absence of such withholding or deduction
("Additional Amounts"), except that no such Additional Amounts shall be payable:

          (a) to, or to a Person on behalf of, a Holder who is liable for such
     Gross-Up Taxes in respect of this Security or the Guarantee of this
     Security by reason of such Holder having some connection with the relevant
     Taxing Jurisdiction (including a citizen or resident or national of, or
     carrying on a business or maintaining a permanent establishment in, or
     being physically present in, such Taxing Jurisdiction) other than the mere
     holding of this Security or the receipt of principal of, premium, if any,
     and interest in respect thereof or in respect of the Guarantee of this
     Security;

          (b) to, or to a Person on behalf of, a Holder who presents this
     Security (where presentation is required) for payment more than 30 days
     after the Relevant Date except to the extent that the Holder would have
     been entitled to such Additional Amounts on presenting this Security for
     payments on the last day of such period of 30 days;

          (c) to, or to a Person on behalf of, a Holder who presents a Security
     (where presentation is required) in the United Kingdom or Cayman Islands;

          (d) to, or to a Person on behalf of, a Holder who would not be liable
     or subject to the withholding or deduction by making a declaration of
     nonresidence or similar claim for exemption to the relevant tax authority;
     or

          (e) to, or to a Person on behalf of, a Holder of a definitive
     Registered Security issued pursuant to the request of owners of interests



                                      B-3

 
     representing a majority in outstanding principal amount in the Book-Entry
     Interest following and during the continuance of an Event of Default if
     such Holder (or any predecessor Holder) was one of such owners requesting
     that definitive Registered Securities be so issued.

     Such Additional Amounts will also not be payable where, had the beneficial
owner of the Security (or any interest therein) been the Holder of the Security,
he would not have been entitled to payment of Additional Amounts by reason of
any one or more of clauses (a) through (e) above. If the Company or the
Guarantor, as applicable, shall determine that Additional Amounts will not be
payable because of the immediately preceding sentence, the Company or the
Guarantor, as applicable, will inform such Holder promptly after making such
determination setting forth the reason(s) therefor.

     "Relevant Date" means whichever is the later of (i) the date on which such
payment first becomes due and (ii) if the full amount payable has not been
received in The City of New York by the Trustee or the Holder on or prior to
such due date, the date on which, the full amount having been so received,
notice to that effect shall have been given to the Holder in accordance with
this Indenture.

     References to principal of, and premium or interest in respect of, this
Security or payments under the Guarantee of this Security shall be deemed to
include to any Additional Amounts which may be payable as set forth in the
Indenture or in this Security.

     The Company shall furnish to the Trustee the official receipts (or a
certified copy of the official receipts) evidencing payment of Gross-Up Taxes.
Copies of such receipts shall be made available to the Holder of this Security
upon request.

     So long as the Securities of this series are listed on the Luxembourg Stock
Exchange and the rules of the Luxembourg Stock Exchange so require, notices to
Holders of Securities of this series will be published in a leading newspaper
having general circulation in Luxembourg (which is expected to be the
Luxemburger Wort).

     REFERENCE IS HEREBY MADE TO THE FURTHER PROVISIONS OF THIS SECURITY SET
FORTH ON THE REVERSE HEREOF, WHICH FURTHER PROVISIONS SHALL FOR ALL PURPOSES
HAVE THE SAME EFFECT AS IF SET FORTH AT THIS PLACE.

     Unless the certificate of authentication hereon has been executed by the
Trustee referred to on the reverse hereof by manual signature, this Security
shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.


                                      B-4

 
     IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed by an authorized signatory of the Company.

                                            YORKSHIRE POWER FINANCE
                                            LIMITED



                                            By _________________________________
                                               Authorized Signatory

                          CERTIFICATE OF AUTHENTICATION

     This is one of the Securities of the series designated herein and referred
to in the within-mentioned Indenture.


                                            THE BANK OF NEW YORK,
                                            as Trustee


                                            By:_________________________________
                                               Authorized Signatory


Dated:


                                      B-5

 
                          [Form of Reverse of Security]

                         YORKSHIRE POWER FINANCE LIMITED
             ___% Junior Subordinated Deferrable Interest Debenture,
                          Series A due __________, 2038

     This Security is one of a duly authorized issue of securities of the
Company (herein called the "Securities"), issued and to be issued in one or more
series under an Indenture, dated as of May 1, 1998 (herein called the "Original
Indenture"), among the Company, Yorkshire Power Group Limited, as guarantor (the
"Guarantor"), The Bank of New York, as trustee principal paying agent, register
and transfer agent (herein called the "Trustee", which term includes any
successor trustee under the Indenture), and Banque Generale du Luxembourg S.A.,
as paying and transfer agent (the "Paying and Transfer Agent"), as supplemented
by the First Supplemental Indenture, dated as of May __, 1998 (together with the
Original Indenture and any other supplements thereto, the "Indenture") among the
Company, the Guarantor, the Trustee and the Paying and Transfer Agent to which
Indenture and all indentures supplemental thereto reference is hereby made for a
statement of the respective rights, limitations of rights, duties and immunities
thereunder of the Company, the Guarantor, the Trustee, the Paying and Transfer
Agent and the Holders of the Securities and of the terms upon which the
Securities are, and are to be, authenticated and delivered. This Security is one
of the series designated on the face hereof, limited in aggregate principal
amount to $275,000,000.

     The Company shall have the right, subject to the terms and conditions of
the Indenture, to redeem this Security at any time on or after ___________,
2003, at the option of the Company, without premium or penalty, in whole or in
part, at a Redemption Price equal to 100% of the principal amount to be redeemed
plus any accrued and unpaid interest, including Additional Interest, if any, to
the Redemption Date. Upon the occurrence of a Special Event (as defined below)
at any time, the Company may, within 90 days following the occurrence thereof
and subject to the terms and conditions of the Indenture, redeem this Security
without premium or penalty, in whole, at a Redemption Price equal to 100% of the
principal amount thereof plus any accrued and unpaid interest, including
Additional Interest, if any, to the Redemption Date. A Special Event may be a
Tax Event or an Investment Company Act Event.

"Tax Event" means the receipt by the Guarantor or the Company of an opinion of
independent counsel (which may be counsel to the Guarantor or its affiliates)
experienced in such matters to the effect that there has been (a) any amendment
to, or change (including any announced prospective change) in, the laws (or any
regulations thereunder) of any supra national federation to which the United
Kingdom belongs or the jurisdiction (or any political subdivision or taxing
authority thereof or therein) in which the Company or the Guarantor is
incorporated or created, as applicable, or in which the Company or the Guarantor
is managed or has a place of business (each, a "Taxing Jurisdiction"), (b) any
official administrative pronouncement or judicial decision interpreting,
clarifying or applying such laws or regulations or (c) a threatened challenge
asserted by a government or taxing authority with respect to the Guarantor or
any of its



                                      B-6

 
subsidiaries, or a threatened challenge asserted in writing by a government or
taxing authority against any other taxpayer that has raised capital through the
issuance of securities that are substantially similar to the Securities or the
Trust Securities, which amendment or change is effective or which pronouncement
clarification, challenge or decision is announced on or after May __, 1998, and
that results in their being more than an insubstantial risk that (i) the Company
is, or will be within 90 days of the date thereof , subject to income tax within
a Taxing Jurisdiction (other than the United Kingdom corporation income tax)
with respect to interest received or accrued on the Intercompany Notes, (ii) the
Company is, or will be within 90 days of the date thereof, subject to more than
a de minimis amount of other tax, duties or other governmental charges, (iii)
interest payable by the Company on the Securities is not, or within 90 days of
the date thereof will not be, deductible, in whole or in part for United States
Federal income tax or United Kingdom corporation income tax purposes, as they
accrue by the Company or by a member of any tax group to which the Guarantor
belongs or (iv) interest payable with respect to the Intercompany Notes by the
Guarantor or its affiliates is not, or within 90 days of the date thereof will
not be, deductible, in whole or in part, for (as appropriate) United States
Federal or United Kingdom corporation income tax purposes, by one of (as
appropriate) the Guarantor, its shareholders or a member of any tax group to
which the Guarantor belongs. "Investment Company Act Event" shall mean that the
Guarantor or the Company shall have received an opinion of independent counsel
(which may be counsel to the Guarantor or its affiliates) experienced in such
matters to the effect that, as a result of the occurrence of a change in law or
regulation or a change in interpretation or application of law or regulation by
any legislative body, court, governmental agency or regulatory authority (an
"Investment Company Act Change"), there is more than an insubstantial risk that
the Guarantor or the Company is or will be considered an "investment company"
that is required to be registered under the Investment Company Act of 1940, as
amended, which Investment Company Act Change becomes effective on or after May
__, 1998.

     Notice of redemption shall be given as provided in the Indenture not less
than 30 days nor more than 60 days prior to the date fixed for redemption.

     If fewer than all the Securities of this series are to be redeemed,
selection of Securities for redemption will be made by the Trustee in any manner
the Trustee deems fair and appropriate and that complies with applicable legal
and securities exchange requirements.

     Unless the Company defaults in payment of the redemption price, from and
after the redemption date, the Securities of this series or portions thereof
called for redemption will cease to bear interest, and the Holders thereof will
have no right in respect to such Securities of this series except the right to
receive the redemption price thereof.

     In the event of redemption of this security in part only, a new Security or
Securities of this series and of like tenor for the unredeemed portion hereof
will be issued in the name of the Holder hereof upon the cancellation hereof.



                                      B-7

 
     If an Event of Default with respect to Securities of this series shall
occur and be continuing, the principal of the Securities of this series may be
declared due and payable in the manner and with the effect provided in the
Indenture. At any time after such declaration of acceleration with respect to
Securities of any series has been made, but before a judgment or decree for
payment of money has been obtained by the Trustee as provided in the Indenture,
if all Events of Default with respect to Securities of this series have been
cured or waived (other than the nonpayment of principal of the Securities which
has become due solely by reason of such declaration of acceleration) then such
declaration of acceleration and its consequences shall be automatically annulled
and rescinded.

     The Securities of this series are subject to redemption upon not less than
30 nor more than 60 days' notice to the Holders of Securities by first-class
mail, at a price equal to the outstanding principal amount thereof, together
with Additional Amounts, if any, and accrued interest, if any, to the Redemption
Date if (a) the Company or the Guarantor satisfies the Trustee prior to the
giving of such notice that it has or will become obligated to pay Additional
Amounts with respect to the Securities or the Guarantee as a result of either
(i) any change in, or amendment to, the laws or regulations of a Taxing
Jurisdiction or any political subdivision or any authority or agency thereof or
therein having power to tax or levy duties, or any change in the application or
interpretation of such laws or regulations, which change or amendment becomes
effective on or after May __, 1998 or (ii) the issuance of Definitive Registered
Series A Notes as a result of: (A) DTC having notified the Company and the
Book-Entry Depositary that it was unwilling or unable to continue to hold the
Book-Entry Interests or at any time ceasing to be a "clearing agency" registered
as such under the Securities Exchange Act of 1934 and, in either case, a
successor is not being appointed by the Company within 120 days; (B) the
Book-Entry Depositary for the Securities of this series having notified the
Company that it was unwilling or unable to continue as Book-Entry Depositary
with respect to a Global security of this series and no successor Book-Entry
Depositary having been appointed by the Company within 120 days or (C) an Event
of Default with respect to the Securities of this series having occurred and
being continuing and a Holder, in such circumstance, having requested in writing
that a Global Bearer Series A Notes be exchanged for one or more Definitive
Registered Series A Notes and (b) such obligation cannot be avoided by the
Company and the Guarantor taking reasonable measures available to it, subject,
as provided in the Indenture, to the delivery by the Company or the Guarantor of
an Officers Certificate that such obligation referred to in (a) cannot be
avoided by the Company or the Guarantor taking reasonable measures available to
it.

     The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the Indenture or any supplemental
indenture or the rights and obligations of the Company and the rights of the
Holders of the Securities of each series to be affected under the Indenture at
any time by the Company and the Trustee with the consent of the Holders of a
majority in aggregate principal amount of the Securities at the time Outstanding
of all series to be affected (voting as a class). The Indenture also contains
provisions permitting the Holders of specified percentages in principal amount
of the securities of each series at the time Outstanding, on behalf of the
Holders of all Securities of such series, to waive compliance by the



                                      B-8

 
Company with certain provisions of the Indenture and certain past defaults under
the Indenture and their consequences. Any such consent or waiver by the Holder
of this Security shall be conclusive and binding upon such Holder and upon all
future Holders of this Security and of any Security issued upon the registration
of transfer hereof or in exchange herefor or in lieu hereof, whether or not
notation of such consent or waiver is made upon this Security.

     No reference herein to the Indenture and no provision of this Security or
of the Indenture shall alter or impair the obligation of the Company, which is
absolute and unconditional, to pay the principal of, premium, if any, and
interest, if any, on this Security and all payments made pursuant to the
Guarantee of the Security at the times, place and rate, and in the coin or
currency, herein prescribed.

     As provided in the Indenture and subject to certain limitations therein set
forth, the transfer of this Security is registrable in the Security Register,
upon surrender of this Security for registration of transfer at the office or
agency of the Company in any place where the principal of, premium, if any, and
interest, if any, on this Security are payable, duly endorsed by, or accompanied
by a written instrument of transfer in form satisfactory to the Company and the
Security Registrar duly executed by the Holder hereof or his attorney duly
authorized in writing, and thereupon one or more new Securities of this series
and of like tenor, of authorized denominations and for the same aggregate
principal amount, will be issued to the designated transferee or transferees.

     The Securities of this series are issuable only in registered form without
coupons in denominations of $25 and any integral multiple thereof. As provided
in the Indenture and subject to certain limitations therein set forth,
Securities of this series are exchangeable for a like aggregate principal amount
of Securities of this series and of like tenor of a different authorized
denomination, as requested by the Holder surrendering the same.

     No service charge shall be made for any such registration of transfer or
exchange, but the Company may require payment of a sum sufficient to cover any
tax or other governmental charge payable in connection therewith.

     Prior to due presentment of this Security for registration of transfer, the
Company, the Trustee and any agent of the Company or the Trustee may treat the
Person in whose name this Security is registered as the owner hereof for all
purposes, whether or not this Security be overdue, and neither the Company, the
Trustee nor any such agent shall be affected by notice to the contrary.

     When a successor assumes all the obligations of its predecessor under the
Securities of this series and the Indenture in accordance with the terms of the
Indenture, the predecessor will be released from those obligations.

     The Trustee under the Indenture, in its individual or any other capacity,
may become the owner or pledge of Securities of this series and may otherwise
deal with the Company, its Subsidiaries or their respective Affiliates as if it
were not the Trustee.



                                      B-9

 
     No stockholder, director, officer, employee, incorporator or Affiliate of
the Company shall have any liability for any obligation of the Company under the
Securities of this series or the Indenture or for any claim based on, in respect
of or by reason of, such obligations or their creation. Each Holder of the
Securities of this series by accepting a Security of this series waives and
releases all such liability. The waiver and release are part of the
consideration for the issuance of the Securities of this series.

     This Security shall not be valid until the Trustee or authenticating agent
signs the certificate of authentication on this Security.

     Customary abbreviations may be used in the name of a Holder of a Securities
of this series or an assignee, such as: TEN COM (= tenants in common), TEN ENT
(= tenants by the entireties), JT TEN (= joint tenants with right of
survivorship and not as tenants in common), CUST (= Custodian), and U/G/M/A (=
Uniform Gifts to Minors Act).

     Pursuant to a recommendation promulgated by the Committee on Uniform
Security Identification Procedures, the Company will cause CUSIP numbers to be
printed on the Securities of this series as a convenience to the Holders of the
Securities of this series. No representation is made as to the accuracy of such
numbers as printed on the Securities of this series and reliance may be placed
only on the other identification numbers printed hereon.

     This Security shall be governed by and construed in accordance with the
laws of the State of New York.

     All terms used in this Security which are defined in the Indenture shall
have the meanings assigned to them in the Indenture.


                                      B-10

 
                                    GUARANTEE

     FOR VALUE RECEIVED, YORKSHIRE POWER GROUP LIMITED, a company duly
incorporated and existing under the laws of England and Wales (the "Guarantor",
which term includes any successor Person under the Indenture referred to in the
Security on which this notation is endorsed), hereby fully and unconditionally
guarantees to the Holder of the accompanying Security issued by Yorkshire Power
Finance Limited (the "Company"), pursuant to the terms of the Guarantee
contained in Article XV of the Indenture, the due and punctual payment of the
principal of, premium, if any, and interest in respect of this Security (and any
Additional Amounts payable in respect thereof), when and as the same shall
become due and payable, whether at Stated Maturity, by declaration of
acceleration, call for redemption or otherwise, in accordance with the terms of
this Security and the Indenture. In case of the failure of the Company
punctually to pay any such principal, premium, if any, or interest, the
Guarantor hereby agrees to cause any such payment to be made punctually when and
as the same shall become due and payable as if such payment were made by the
Company.

     The obligations of the Guarantor to the Holders of the Securities and to
the Trustee pursuant to the Guarantee and the Indenture are expressly set forth
in Article XV of the Indenture, and reference is hereby made to such Article and
Indenture for the precise terms of the Guarantee.

     THIS GUARANTEE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE
LAWS OF THE STATE OF NEW YORK.

     The Guarantee shall not be valid or obligatory for any purpose until the
certificate of authentication on the Security upon which this notation of the
Guarantee is endorsed shall have been executed by the Trustee under the
Indenture by the manual signature of one of its authorized officers.

                                            YORKSHIRE POWER GROUP LIMITED

                                            By:_________________________________
                                               Authorized Signatory


                                      B-11