Exhibit 4.9









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                      COMMON SECURITIES GUARANTEE AGREEMENT
                           Southern Investments UK plc
                          Dated as of January 29, 1997
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                                TABLE OF CONTENTS

                                                                           Page


ARTICLE I
                         DEFINITIONS AND INTERPRETATION

SECTION 1.1.  Definitions Interpretation...................................  2

ARTICLE II
                       GUARANTEE

SECTION 2.1.  Guarantee....................................................  3
SECTION 2.2.  Waiver of Notice and Demand..................................  3
SECTION 2.3.  Obligations Not Affected.....................................  3
SECTION 2.4.  Rights of Holders............................................  4
SECTION 2.5.  Guarantee of Payment.........................................  4
SECTION 2.6.  Subrogation..................................................  5
SECTION 2.7.  Independent Obligations......................................  5

ARTICLE III
                    LIMITATION OF TRANSACTIONS; SUBORDINATION

SECTION 3.1. Limitation of Transactions...................................   5
SECTION 3.2. Ranking......................................................   6

ARTICLE IV
                     TERMINATION

SECTION 4.1. Termination..................................................   6

ARTICLE V
                    MISCELLANEOUS

SECTION 5.1. Successors and Assigns.......................................   7
SECTION 5.2. Amendments...................................................   7
SECTION 5.3. Notices......................................................   7
SECTION 5.4. Benefit......................................................   8
SECTION 5.5. Governing Law................................................   8







                      COMMON SECURITIES GUARANTEE AGREEMENT


                  This GUARANTEE AGREEMENT (the "Common Securities Guarantee"),
dated as of January 29, 1997, is executed and delivered by Southern Investments
UK plc, a public limited liability company incorporated under the Companies Act
1985 in England and Wales (the "Guarantor"), for the benefit of the Holders (as
defined herein) from time to time of the Common Securities (as defined herein)
of Southern Investments UK Capital Trust I, a Delaware business trust (the
"Trust").

                  WHEREAS, pursuant to an Amended and Restated Declaration of
Trust (the "Declaration"), dated as of January 29, 1997, among the Trustees of
the Trust named therein, the Guarantor, as sponsor, and the holders from time to
time of undivided beneficial interests in the assets of the Trust, the Trust is
issuing on the date hereof 2,537 common securities designated the 8.23% Common
Securities (the "Common Securities"), having an aggregate stated liquidation
amount of $2,537,000 to meet the capital requirements of the Trust;

                  WHEREAS, as incentive for the Holders to purchase the Common
Securities, the Guarantor desires irrevocably and unconditionally to agree, to
the extent set forth in this Common Securities Guarantee, to pay to the holders
of the Common Securities the Guarantee Payments (as defined herein) and to make
certain other payments on the terms and conditions set forth herein; and

                  WHEREAS, the Guarantor is also executing and delivering a
guarantee agreement (the "Capital Securities Guarantee") for the benefit of the
holders of the Capital Securities (as defined in the Declaration) and upon
consummation of the Exchange Offer (as defined in the Declaration) will execute
and deliver a guarantee agreement (the "Exchange Capital Securities Guarantee")
for the benefit of the holders of the Exchange Capital Securities (as defined in
the Declaration), each in substantially identical terms to this Common
Securities Guarantee, except that if an Event of Default (as defined in the
Declaration) has occurred and is continuing, the rights of Holders of the Common
Securities to receive Guarantee Payments under this Common Securities Guarantee
are subordinated to the rights of holders of the Capital Securities to receive
guarantee payments under the Capital Securities Guarantee and the Exchange
Capital Securities Guarantee, as the case may be.

                  NOW, THEREFORE, in consideration of the purchase by each
holder of Common Securities, which purchase the Guarantor hereby acknowledges
shall benefit the Guarantor, the Guarantor executes and delivers this Common
Securities Guarantee for the benefit of the Holders.


                                    ARTICLE I
                         DEFINITIONS AND INTERPRETATION

                  SECTION 1.1.......Definitions Interpretation

                  In this Common Securities Guarantee, unless the context
otherwise requires:

                  (a) capitalized terms used in this Common Securities Guarantee
         but not defined in the preamble above have the respective meanings
         assigned to them in this Section 1.1;

                  (b) terms defined in the Declaration as at the date of
         execution of this Common Securities Guarantee have the same meaning
         when used in this Common Securities Guarantee unless otherwise defined
         in this Common Securities Guarantee;

               (c) a term defined anywhere in this Common  Securities  Guarantee
          has the same meaning throughout;

                  (d) all references to "the Common Securities Guarantee" or
         "this Common Securities Guarantee" are to this Common Securities
         Guarantee as modified, supplemented or amended from time to time;

               (e)  all  references  in  this  Common  Securities  Guarantee  to
          Articles  and  Sections  are to Articles  and  Sections of this Common
          Securities Guarantee unless otherwise specified; and

               (f) a  reference  to the  singular  includes  the plural and vice
          versa.

                  "Guarantee Payments" means the following payments or
distributions, without duplication, with respect to the Common Securities, to
the extent not paid or made by or on behalf of the Trust: (i) any accrued and
unpaid Distributions that are required to be paid on such Common Securities to
the extent the Trust has funds on hand legally available therefor at such time,
(ii) the redemption price, including all accrued and unpaid Distributions to the
date of redemption (the "Redemption Price"), to the extent the Trust has funds
on hand legally available therefor at such time, with respect to any Common
Securities called for redemption by the Trust, and (iii) upon a voluntary or
involuntary dissolution, winding-up or termination of the Trust (other than in
connection with the distribution of Debentures to the Holders in exchange for
Common Securities as provided in the Declaration), the lesser of (a) the
aggregate of the liquidation amount and all accrued and unpaid Distributions on
the Common Securities to the date of payment, to the extent the Trust has funds
on hand legally available therefor, and (b) the amount of assets of the Trust
remaining available for distribution to Holders in liquidation of the Trust (in
either case, the "Liquidation Distribution"). If an Event of Default has
occurred and is continuing, no Guarantee Payments with respect to the Common
Securities shall be made until holders of Capital Securities shall be paid in
full the Guarantee Payments to which they are entitled under the Capital
Securities Guarantee and the Exchange Capital Securities Guarantee, as the case
may be.

     "Holder"  means any holder,  as  registered on the books and records of the
Trust, of any Common Securities.


                                   ARTICLE II
                                    GUARANTEE

                  SECTION 2.1.......Guarantee

                  The Guarantor irrevocably and unconditionally agrees to pay in
full to the Holders the Guarantee Payments (without duplication of amounts
theretofore paid by or on behalf of the Trust), as and when due, to the extent
not paid by the Trust, regardless of any defense, right of set-off or
counterclaim which the Trust may have or assert. The Guarantor's obligation to
make a Guarantee Payment may be satisfied by direct payment of the required
amounts by the Guarantor to the Holders or by paying the required amount to the
Trust and causing the Trust to pay such amounts to the Holders.

                  SECTION 2.2.......Waiver of Notice and Demand

                  The Guarantor hereby waives notice of acceptance of this
Common Securities Guarantee and of any liability to which it applies or may
apply, presentment, demand for payment, any right to require a proceeding first
against the Trust or any other Person before proceeding against the Guarantor,
protest, notice of nonpayment, notice of dishonor, notice of redemption and all
other notices and demands.

                  SECTION 2.3.......Obligations Not Affected

                  The obligations, covenants, agreements and duties of the
Guarantor under this Common Securities Guarantee shall in no way be affected or
impaired by reason of the happening from time to time of any of the following:

                  (a) the release or waiver, by operation of law or otherwise,
         of the performance or observance by the Trust of any express or implied
         agreement, covenant, term or condition relating to the Common
         Securities to be performed or observed by the Trust;

                  (b) the extension of time for the payment by the Trust of all
         or any portion of the Distributions, Redemption Price, Liquidation
         Distribution or any other sums payable under the terms of the Common
         Securities or the extension of time for the performance of any other
         obligation under, arising out of, or in connection with, the Common
         Securities (other than an extension of time for payment of
         Distributions, Redemption Price, Liquidation Distribution or other sum
         payable that results from the extension of any interest payment period
         on the Debentures permitted by the Indenture);

                  (c) any failure, omission, delay or lack of diligence on the
         part of the Holders to enforce, assert or exercise any right,
         privilege, power or remedy conferred on the Holders pursuant to the
         terms of the Common Securities, or any action on the part of the Trust
         granting indulgence or extension of any kind;

                  (d) the voluntary or involuntary liquidation, dissolution,
         sale of any collateral, receivership, insolvency, bankruptcy,
         assignment for the benefit of creditors, reorganization, arrangement,
         composition or readjustment of debt of, or other similar proceedings
         affecting, the Trust or any of the assets of the Trust;

               (e) any  invalidity  of, or defect or  deficiency  in, the Common
          Securities;

               (f) the  settlement or compromise  of any  obligation  guaranteed
          hereby or hereby incurred; or

                  (g) any other circumstance whatsoever that might otherwise
         constitute a legal or equitable discharge or defense of a guarantor, it
         being the intent of this Section 2.3 that the obligations of the
         Guarantor with respect to the Guarantee Payments shall be absolute and
         unconditional under any and all circumstances.

There shall be no obligation of the Holders to give notice to, or obtain consent
of, the Guarantor with respect to the happening of any of the foregoing.

                  SECTION 2.4.......Rights of Holders

                  The Guarantor expressly acknowledges that any Holder may
institute a legal proceeding directly against the Guarantor to enforce its
rights under this Common Securities Guarantee, without first instituting a legal
proceeding against the Trust or any other Person.

                  SECTION 2.5.......Guarantee of Payment

                  This Common Securities Guarantee creates a guarantee of
payment and not of collection.

                  SECTION 2.6.......Subrogation

                  The Guarantor shall be subrogated to all (if any) rights of
the Holders against the Trust in respect of any amounts paid to such Holders by
the Guarantor under this Common Securities Guarantee; provided, however, that
the Guarantor shall not (except to the extent required by mandatory provisions
of law) be entitled to enforce or exercise any rights which it may acquire by
way of subrogation or any indemnity, reimbursement or other agreement, in all
cases as a result of payment under this Common Securities Guarantee, if, at the
time of any such payment, any amounts are due and unpaid under this Common
Securities Guarantee. If any amount shall be paid to the Guarantor in violation
of the preceding sentence, the Guarantor agrees to hold such amount in trust for
the Holders and to pay over such amount to the Holders.

                  SECTION 2.7.......Independent Obligations

                  The Guarantor acknowledges that its obligations hereunder are
independent of the obligations of the Trust with respect to the Common
Securities and that the Guarantor shall be liable as principal and as debtor
hereunder to make Guarantee Payments pursuant to the terms of this Common
Securities Guarantee notwithstanding the occurrence of any event referred to in
subsections (a) through (g), inclusive, of Section 2.3 hereof.


                                   ARTICLE III
                    LIMITATION OF TRANSACTIONS; SUBORDINATION

                  SECTION 3.1.......Limitation of Transactions

                  So long as any Common Securities remain outstanding, the
Guarantor will not (a) declare or pay any dividends on, or redeem, purchase,
acquire or make a distribution or liquidation payment with respect to, any of
the Guarantor's capital stock except for dividends, payments or distributions
payable in shares of the Guarantor's capital stock, reclassifications of its
capital stock and conversions or exchanges of capital stock of one class or
series for capital stock of another class or series and except for a redemption,
purchase or other acquisition of shares of or its capital stock made for the
purpose of an employee incentive plan or benefit plan or other similar
arrangement of the Guarantor or any of its subsidiaries or (b) make any payment
of interest, principal of or premium, if any, on or repay, repurchase or redeem
any debt securities issued by the Guarantor that rank pari passu with or junior
in right of payment to the Debentures (except by conversion into or exchange for
shares of its capital stock) or (c) make any guarantee payments with respect to
the foregoing, if at such time (i) the Guarantor shall be in default with
respect to its Guarantee Payments or other payment obligations under this
Capital Securities Guarantee Agreement; (ii) there shall have occurred and be
continuing an event of default under the Indenture or (iii) the Guarantor shall
have given notice of its election of the exercise of its right to extend the
interest payment period pursuant to Section 313 of the Indenture and any such
extension, or any extension thereof, shall be continuing. So long as any Capital
Securities remain outstanding, the Guarantor (i) will remain the sole direct or
indirect owner of all of the outstanding Common Securities and shall not cause
or permit the Common Securities to be transferred except to the extent permitted
by the Declaration; provided, that any permitted successor of the Guarantor
under the Indenture may succeed to the Guarantor's ownership of the Common
Securities, and (ii) will not take any action which will cause the Trust to
cease to be treated as a grantor trust for United States federal income tax
purposes except in connection with a distribution of Debentures.

                  SECTION 3.2.......Ranking

                  This Common Securities Guarantee will constitute an unsecured
obligation of the Guarantor and will rank (i) subordinate and junior in right of
payment to all other liabilities of the Guarantor, including the Debentures,
except liabilities made pari passu or subordinate by their terms, and (ii)
senior to all capital stock now or hereafter issued by the Guarantor, and to any
guarantee now or hereafter entered into by the Guarantor in respect of any of
its capital stock.


                                   ARTICLE IV
                                   TERMINATION

                  SECTION 4.1.......Termination

                  This Common Securities Guarantee shall terminate and be of no
further force and effect (i) upon full payment of the Redemption Price of all
Common Securities, (ii) upon the distribution of the Debentures to the Holders
of all of the Common Securities or (iii) upon full payment of the amounts
payable in accordance with the Declaration upon liquidation of the Trust.
Notwithstanding the foregoing, this Common Securities Guarantee will continue to
be effective or will be reinstated, as the case may be, if at any time any
Holder must restore payment of any sums paid with respect to the Common
Securities or this Common Securities Guarantee.


                                    ARTICLE V
                                  MISCELLANEOUS

                  SECTION 5.1.......Successors and Assigns

                  All guarantees and agreements contained in this Common
Securities Guarantee shall bind the successors, assigns, receivers, trustees and
representatives of the Guarantor and shall inure to the benefit of the Holders
of the Common Securities then outstanding. Except in connection with a
consolidation, merger, conveyance, transfer, lease or sale involving the
Guarantor that is permitted under the Indenture, the Guarantor may not assign
its obligations under this Common Capital Securities Guarantee.

                  SECTION 5.2.......Amendments

                  Except with respect to any changes which do not adversely
affect the rights of Holders (in which case no consent of Holders will be
required), this Common Securities Guarantee may only be amended with the prior
approval of the Holders of at least a majority in liquidation amount of all the
outstanding Common Securities. The provisions of Section 12.2 of the Declaration
with respect to meetings of Holders of the Securities apply to the giving of
such approval.

                  SECTION 5.3.......Notices

                  All notices provided for in this Common Securities Guarantee
shall be in writing, duly signed by the party giving such notice, and shall be
delivered, telecopied or mailed by registered or certified mail, as follows:

                  (a) if given to the Trust, in care of the Regular Trustees at
         the mailing address set forth below (or such other address as the Trust
         may give notice of to the Holders):

            Southern Investments UK Capital Trust I
            c/o Southern Investments UK plc
            800 Park Avenue
            Aztec West
            Almondsbury, Bristol BS12 4SE
            England
            Attention:       Charl Oosthuizen
            Telecopy:        011-44-1454-452-361

            and

            Southern Investments UK Capital Trust I
            c/o Southern Company Services, Inc.
            64 Perimeter Center East
            Atlanta, GA  30346-6401
            Attention:       Wayne Boston or Richard Childs, Regular Trustees
            Telecopy:        770-821-2894

                  (b) if given to the Guarantor, at the Guarantor's mailing
         address set forth below (or such other address as the Guarantor may
         give notice of to the Holders:

                           Southern Investments UK plc
                           800 Park Avenue
                           Aztec West
                           Almondsbury, Bristol BS12 4SE
                           Attention:       Charl Oosthuizen
                           Telecopy:        001-44-1454-452-361

               (c) if given to any Holder, at the address set forth on the books
          and records of the Trust.

                  All such notices shall be deemed to have been given when
received in person, telecopied with receipt confirmed, or mailed by first class
mail, postage prepaid except that if a notice or other document is refused
delivery or cannot be delivered because of a changed address of which no notice
was given, such notice or other document shall be deemed to have been delivered
on the date of such refusal or inability to deliver.

                  SECTION 5.4.      Benefit

                  This Common Securities Guarantee is solely for the benefit of
the Holders of the Common Securities and is not separately transferable from the
Common Securities.

                  SECTION 5.5.      Governing Law

                  THIS COMMON SECURITIES GUARANTEE SHALL BE GOVERNED BY, AND
CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK,
WITHOUT REGARD TO CONFLICTS OF LAWS PRINCIPLES THEREOF.





                  THIS COMMON SECURITIES GUARANTEE is executed as of the day and
 year first above written.


                                 SOUTHERN INVESTMENTS UK PLC




                                 By:
                                      Name:
                                      Title: