Exhibit 10.31-d





                         THIRD AMENDING AGREEMENT TO THE
                         KEYSPAN ENERGY DEVELOPMENT CO.
                   CREDIT AGREEMENT DATED AS OF JULY 29, 1999

                                     AMONG:

                         KEYSPAN ENERGY DEVELOPMENT CO.

                                   as Borrower

                                     - and -

                              ROYAL BANK OF CANADA,
                      JPMORGAN CHASE BANK, TORONTO BRANCH,
                                BANK OF MONTREAL,
                  BANK ONE, NATIONAL ASSOCIATION, CANADA BRANCH
                          AND ALBERTA TREASURY BRANCHES

                                   as Lenders

                                     - and -

                              ROYAL BANK OF CANADA

                             as Administrative Agent






                                December 20, 2002





<PAGE>

     THIS THIRD AMENDING AGREEMENT dated as of the 20th day of December, 2002

AMONG:

          KEYSPAN  ENERGY  DEVELOPMENT  CO., a Nova Scotia  unlimited  liability
          company (hereinafter referred to as the "Borrower")

                                                         OF THE FIRST PART

                                     - and -

          ROYAL BANK OF CANADA,  JPMORGAN CHASE BANK,  TORONTO  BRANCH,  BANK OF
          MONTREAL,  BANK ONE, NATIONAL  ASSOCIATION,  CANADA BRANCH AND ALBERTA
          TREASURY BRANCHES (hereinafter  sometimes  collectively referred to as
          the "Lenders")

                                                         OF THE SECOND PART

                                     - and -

          ROYAL  BANK OF  CANADA,  a Canadian  chartered  bank,  as agent of the
          Lenders  hereunder  (hereinafter  referred  to as the  "Administrative
          Agent")

                                                         OF THE THIRD PART

     WHEREAS Keyspan Energy  Development Co. as Borrower,  Royal Bank of Canada,
JPMorgan Chase Bank,  Toronto Branch (formerly known as The Chase Manhattan Bank
of Canada),  The  Toronto-Dominion  Bank, Bank of Montreal,  Bank One,  National
Association,  Canada Branch (formerly known as First Chicago NBD Bank,  Canada),
Alberta Treasury  Branches and National Bank of Canada as Lenders and Royal Bank
of Canada as Administrative  Agent entered into a credit agreement  (referred to
herein as the "Credit Agreement") dated as of July 29, 1999;

     AND WHEREAS the Borrower,  the Lenders and the Administrative Agent entered
into a first amending  agreement dated as of October 13, 2000 in connection with
the Borrower incurring  indebtedness of up to Cdn.  $125,000,000 for purposes of
financing  the  purchase  of Gulf  Canada  Resources  Limited's  then  remaining
interest in certain  midstream assets and financing the acquisition,  operation,
maintenance, construction and expansion of gas processing and gathering assets;



<PAGE>


     AND WHEREAS the Borrower , the Lenders and the Administrative Agent entered
into a second  amending  agreement  dated as of December 22, 2000 in  connection
with  the  Borrower  incurring  indebtedness  of up  to  Cdn.  $100,000,000  and
acquiring  certain  Subsidiaries  in  connection  with certain  reorganizational
transactions involving the Borrower and its Subsidiaries;

     AND WHEREAS  the  Borrower  has  requested  that the Lenders  consent to an
amendment to certain provisions set forth in the Credit Agreement;

     AND WHEREAS the Borrower has requested that the Lenders  consent to certain
intercorporate debt transactions involving the Borrower and its Affiliates;

     AND WHEREAS the Lenders have required  that the  Borrower,  the Lenders and
the Administrative  Agent enter into this Third Amending Agreement as one of the
conditions  to the Lenders  providing  their  consent to the  amendment of those
provisions and to those intercorporate debt transactions;

     AND WHEREAS the Borrower,  the Administrative Agent and the Lenders wish to
enter into this Third Amending  Agreement to set forth the changes to the Credit
Agreement,  and to otherwise  confirm the provisions of Amended Credit Agreement
(as that term is defined below);

     NOW  THEREFORE  THIS  AGREEMENT  WITNESSES  that  in  consideration  of the
covenants  and  agreements   herein   contained  and  other  good  and  valuable
consideration,  the  receipt  and  sufficiency  of which is hereby  conclusively
acknowledged  by each of the parties  hereto,  the parties  hereto  covenant and
agree as follows:

1.         Definitions

     All capitalized terms used in this Third Amending  Agreement shall,  unless
otherwise  defined herein,  have the meanings herein given to them in the Credit
Agreement, and:

     "Amended Credit Agreement" means the Credit  Agreement,  as amended by this
     Third Amending  Agreement,  and as it may hereafter be further amended from
     time to time.

     "Credit  Agreement"  means the credit  agreement  dated as of July 29, 1999
     among Keyspan Energy Development Co. as Borrower,  Royal Bank of Canada and
     the other financial institutions named therein from time to time as Lenders
     and Royal Bank of Canada as  Administrative  Agent,  as such  agreement was
     amended by the First Amending Agreement and the Second Amending Agreement.

     "First Amending Agreement" means the amending agreement dated as of October
     13, 2000 among Keyspan Energy  Development  Co. as Borrower,  Royal Bank of
     Canada,  JPMorgan Chase Bank, Toronto Branch,  Bank of Montreal,  Bank One,


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<PAGE>


     National  Association,  Canada  Branch and  Alberta  Treasury  Branches  as
     Lenders and Royal Bank of Canada as Administrative Agent.

     "Intercorporate  Debt  Transactions"  means the transactions  summarized in
     Exhibit "A" hereto, and all actions and matters incidental thereto.

     "Second  Amending  Agreement"  means  the  amending  agreement  dated as of
     December 22, 2000 among Keyspan Energy  Development Co. as Borrower,  Royal
     Bank of Canada, JPMorgan Chase Bank, Toronto Branch, Bank of Montreal, Bank
     One, National  Association,  Canada Branch and Alberta Treasury Branches as
     Lenders and Royal Bank of Canada as Administrative Agent.

     "Third Amending Agreement" means this third amending agreement.

2.    Amendments to Section 1.1 of the Credit Agreement

     Effective as of December 31, 2002,  Section 1.1 of the Credit  Agreement is
     amended by:

     (a)  deleting the chart in the  definition of  "Applicable BA Fee Rate" and
          replacing same with the following chart:

<TABLE>
<CAPTION>
 ---------------------------- ------------------ -------------------- ----------- --------------------- -----------------------
                                   Level 1             Level 2          Level 3          Level 4                Level 5
<S>                              <C>               <C>                  <C>         <C>                     <C>
 Moody's/S&P                      A1/A+ and         A2 and A3/A          Baa1/       Baa2 and Baa3/             Lower than
                                    higher             and A-            BBB+         BBB and BBB-            Baa3/ BBB- or
                                                                                                                 not rated
 ---------------------------- ------------------ -------------------- ----------- --------------------- -----------------------
 Applicable BA Fee Rate            50 bps              60 bps           75 bps          100 bps                  125 bps
 ---------------------------- ------------------ -------------------- ----------- --------------------- -----------------------
</TABLE>

<TABLE>
<CAPTION>
     (b)  deleting the chart in the  definition of  "Applicable  Commitment  Fee
          Rate" and replacing same with the following chart:

 ---------------------------- ------------------ -------------------- ----------- --------------------- -----------------------
                                    Level 1            Level 2         Level 3          Level 4                Level 5
<S>                              <C>                <C>                <C>           <C>                   <C>
 Moody's/S&P                       A1/A+ and         A2 and A3/A        Baa1/         Baa2 and Baa3/         Lower than
                                     higher            and A-           BBB+           BBB and BBB-         Baa3/ BBB- or
                                                                                                              not rated
 ---------------------------- ------------------ -------------------- ----------- --------------------- -----------------------
 Applicable Commitment Fee          11 bps             13.5 bps          15 bps          17.5 bps                20 bps
 Rate
 ---------------------------- ------------------ -------------------- ----------- --------------------- -----------------------
</TABLE>

     (c)  deleting the chart in the definition of "Applicable  LIBOR Margin" and
          replacing same with the following chart:

                                       3
<PAGE>

<TABLE>
<CAPTION>
 ---------------------------- ------------------ -------------------- ----------- --------------------- -----------------------
                                   Level 1             Level 2         Level 3          Level 4                Level 5
<S>                              <C>                 <C>              <C>          <C>                    <C>
 Moody's/S&P                      A1/A+ and           A2 and A3/A       Baa1/        Baa2 and Baa3/          Lower than
                                    higher              and A-          BBB+          BBB and BBB-          Baa3/  BBB- or
                                                                                                              not rated
 ---------------------------- ------------------ -------------------- ----------- --------------------- -----------------------
 Applicable LIBOR Margin           50 bps              60 bps           75 bps          100 bps                125 bps
 ---------------------------- ------------------ -------------------- ----------- --------------------- -----------------------
</TABLE>

     (d)  adding the following  definitions  immediately after the definition of
          "Canadian Prime Rate Loan":

               ""Capital  Lease  Obligations"  means,  as  to  any  Person,  the
               obligations of such Person to pay rent or other amounts under any
               lease of (or other  arrangement  conveying the right to use) real
               or personal property, or a combination thereof, which obligations
               are required to be classified and accounted for as capital leases
               on a  balance  sheet  of such  Person  under  generally  accepted
               accounting  principles  (as  approved  from  time  to time by the
               American  Institute of Chartered  Accountants,  or any  successor
               institute) and, for the purposes of this Agreement, the amount of
               such  obligations  at any time  shall be the  capitalized  amount
               thereof at such time  determined  in  accordance  with  generally
               accepted accounting  principles (as approved from time to time by
               the  Financial   Accounting   Standards  Board  of  the  American
               Institute  of  Certified  Public  Accountants,  or any  successor
               institute).

               "Capital   Stock"   means   any   and  all   shares,   interests,
               participations  or  other  equivalents  (however  designated)  of
               capital stock of a corporation,  any and all equivalent ownership
               interests in a Person (other than a corporation)  and any and all
               warrants, rights or options to purchase any of the foregoing.";

     (e)  deleting  the  definition  of  "Consolidated  Capitalization"  in  its
          entirety and replacing same with the following definition:

               ""Consolidated  Capitalization"  means,  at any date,  the sum of
               Consolidated Net Worth and Consolidated Debt.";

     (f)  deleting the  definition  of  "Consolidated  Debt" in its entirety and
          replacing same with the following definition:

               ""Consolidated  Debt"  means,  at  any  date,  all  Debt  of  the
               Guarantor  and its  Subsidiaries  at such date,  determined  on a
               consolidated   basis  in  accordance   with  generally   accepted
               accounting  principles  (as  approved  from  time  to time by the


                                       4
<PAGE>


               Financial Accounting Standards Board of the American Institute of
               Certified Public  Accountants,  or any successor  institute),  as
               reflected  on  the  balance  sheet  of  the  Guarantor  as at the
               relevant date.";

     (g)  adding the following  definition  immediately  after the definition of
          "Consolidated Net Income":

               ""Consolidated  Net Worth" at any date,  means all  amounts  that
               would,   in  conformity   with  generally   accepted   accounting
               principles  (as  approved  from  time to  time  by the  Financial
               Accounting Standards Board of the American Institute of Certified
               Public Accountants, or any successor institute), be included on a
               consolidated  balance sheet of the Guarantor and its Subsidiaries
               under stockholders' equity at such date.";

     (h)  deleting the  definition of "Debt" in its entirety and replacing  same
          with the following definition:

               ""Debt" of any Person at any date,  means,  without  duplication,
               (a) all  indebtedness of such Person for borrowed money,  (b) all
               obligations  of such Person for the  deferred  purchase  price of
               property or services (other than current trade payables  incurred
               in the  ordinary  course  of  such  Person's  business),  (c) all
               obligations of such Person evidenced by notes, bonds,  debentures
               or other similar  instruments,  (d) all  indebtedness  created or
               arising  under  any  conditional  sale or other  title  retention
               agreement with respect to property  acquired by such Person (even
               though the rights and remedies of the seller or lender under such
               agreement in the event of default are limited to  repossession or
               sale of such property), (e) all Capital Lease Obligations of such
               Person,  (f)  all  obligations  of  such  Person,  contingent  or
               otherwise,  as an account  party  under  acceptances,  letters of
               credit, surety bonds or similar arrangements, (g) the liquidation
               value  of all  preferred  Capital  Stock of such  Person  that is
               redeemable  at the option of the  holder  thereof or that has any
               mandatory  dividend,  redemption or other  required  payment that
               could be required  thereunder  prior to the date that is one year
               after  the  Maturity  Date  of the  last  Commitment  outstanding
               hereunder,  (h)  all  Guarantee  Obligations  of such  Person  in
               respect of  obligations  of the kind  referred  to in clauses (a)
               through (g) above and, in the case of the Borrower, the Guarantor
               and their Subsidiaries,  in addition,  clause (k) below), (i) all
               obligations  of the kind  referred  to in clauses (a) through (h)
               above secured by (or for which the holder of such  obligation has
               an existing right, contingent or otherwise, to be secured by) any


                                       5
<PAGE>


               Security  Interest on property  (including  accounts and contract
               rights)  owned by such  Person,  whether  or not such  Person has
               assumed or become liable for the payment of such obligation,  (j)
               for the  purposes  of  sections  10.1(g),  (h) and (i) only,  all
               obligations  of such Person in respect of Hedge  Agreements,  and
               (k) in the  case  of the  Borrower  ,  the  Guarantor  and  their
               Subsidiaries,  (A) Synthetic  Lease  Obligations  relating to the
               2,200 megawatt  Ravenswood facility located in New York City, and
               (B) any other Synthetic Lease  Obligations of the Guarantor,  the
               Borrower or any of their  Subsidiaries  individually in excess of
               U.S.  $25,000,000;  provided  that,  for  the  purposes  of  this
               Agreement,   (y)  prior  to  the  conversion  to  equity  of  the
               Guarantor's  MEDS Equity Units, 20% of the gross proceeds of such
               securities  shall be  considered  Debt of the  Guarantor  and the
               remaining 80% of such proceeds  shall be considered  equity,  and
               (z) from and after the  conversion  to equity of the  Guarantor's
               MEDS Equity Units,  all of the gross proceeds of such  securities
               shall be considered  equity. The Debt of any Person shall include
               the Debt of any other entity  (including any partnership in which
               such  Person is a general  partner)  to the extent such Person is
               liable therefor as a result of such Person's  ownership  interest
               in or other  relationship with such entity,  except to the extent
               the terms of such Debt expressly  provide that such Person is not
               liable therefor.";

     (i)  adding the following  definition  immediately  after the definition of
          "Guarantee":

               ""Guarantee   Obligation"   means,   as  to   any   Person   (the
               "guaranteeing  person"),  any obligation of (a) the  guaranteeing
               person,  or (b)  another  Person  (including  any bank  under any
               letter of credit) to induce the  creation in respect of which the
               guaranteeing person has issued a reimbursement,  counterindemnity
               or similar  obligation,  in either case guaranteeing or in effect
               guaranteeing  any Debt,  leases,  dividends or other  obligations
               (the  "primary  obligations")  of any  other  third  Person  (the
               "primary obligor") in any manner, whether directly or indirectly,
               including any obligation of the guaranteeing  person,  whether or
               not  contingent,  (i) to purchase any such primary  obligation or
               any property  constituting  direct or indirect security therefor,
               (ii) to advance or supply  funds (1) for the  purchase or payment
               of any  such  primary  obligation,  or (2)  to  maintain  working
               capital or equity capital of the primary  obligor or otherwise to
               maintain the net worth or solvency of the primary obligor,  (iii)
               to purchase  property,  securities or services  primarily for the
               purpose of assuring the owner of any such primary  obligation  of


                                       6
<PAGE>


               the  ability  of the  primary  obligor  to make  payment  of such
               primary obligation,  or (iv) otherwise to assure or hold harmless
               the owner of any such primary  obligation against loss in respect
               thereof;  provided,  however,  that the term Guarantee Obligation
               shall not  include  endorsements  of  instruments  for deposit or
               collection in the ordinary course of business.  The amount of any
               Guarantee  Obligation of any guaranteeing  person shall be deemed
               to be  the  lower  of (a)  an  amount  equal  to  the  stated  or
               determinable amount of the primary obligation in respect of which
               such Guarantee Obligation is made, and (b) the maximum amount for
               which  such  guaranteeing  person may be liable  pursuant  to the
               terms of the  instrument  embodying  such  Guarantee  Obligation,
               unless such primary  obligation  and the maximum amount for which
               such  guaranteeing  person  may  be  liable  are  not  stated  or
               determinable,   in  which  case  the  amount  of  such  Guarantee
               Obligation shall be such guaranteeing person's maximum reasonably
               anticipated  liability in respect  thereof as  determined  by the
               Borrower or the Guarantor in good faith.";

     (j)  adding the following  definition  immediately  after the definition of
          "Hazardous Materials":

               ""Hedge Agreements" means all interest rate swaps, caps or collar
               agreements dealing with interest rates or currency exchange rates
               or the exchange of nominal interest obligations, either generally
               or under specific contingencies.";

     (k)  deleting  the   definition   of  "Keyspan   Luxembourg   Subordination
          Agreement"  in its  entirety  and  replacing  same with the  following
          definition:

               ""Keyspan   Luxembourg   Subordination   Agreement"   means   the
               subordination  agreement  dated as of December 22, 2000 among the
               Borrower,  the Administrative  Agent on behalf of the Lenders and
               Keyspan Luxembourg, as such agreement will be amended pursuant to
               an Amending Agreement to be effective December 31, 2002 and to be
               entered  into among the  Borrower,  the  Administrative  Agent on
               behalf of the Lenders and  Keyspan  Luxembourg  pursuant to which
               the KS  Luxembourg  Credit  Agreement  (as  defined  therein)  is
               amended to reflect the  consolidation  of certain  debts owing by
               the Borrower to Keyspan Luxembourg.";

     (l)  amending the  definition  of "KS Finance Loan" by adding the following
          immediately after paragraph (g) thereof:


                                       7
<PAGE>


               "The  parties  hereto  acknowledge  and agree that the KS Finance
               Loan will be the subject of a  Consolidated  Loan Agreement and a
               Consolidated  Promissory  Note both to be effective  December 31,
               2002 whereby the amounts owing under the Term Loan Agreement will
               be  consolidated  with all  amounts  owing  under  the Term  Loan
               Agreement  dated June 1, 2000  between the  Borrower and Nicodama
               and the Promissory Note ($5,308,677) dated June 1, 2000 issued by
               the  Borrower to  Nicodama,  and that the KS Finance Loan will be
               transferred to Keyspan  Luxembourg  pursuant to an Assignment and
               Assumption  Agreement between Nicodama and Keyspan  Luxembourg to
               be effective December 31, 2002.";

     (m)  deleting  the  definition  of  "Maturity  Date"  in its  entirety  and
          replacing same with the following definition:

               ""Maturity  Date" means,  with respect to a Commitment,  the date
               that is the first anniversary of the Term Date in respect of such
               Commitment;  provided that,  notwithstanding  the foregoing,  the
               Maturity  Date  for  the   Commitment   of  Bank  One,   National
               Association, Canada Branch shall be July 25, 2004.";

     (n)  deleting the definition of "Nicodama  Subordination  Agreement" in its
          entirety and replacing same with the following definition:

               ""Nicodama  Subordination  Agreement" means the subordination and
               postponement  agreement  dated  as of July  29,  1999  among  the
               Borrower,  the Administrative  Agent on behalf of the Lenders and
               KS Finance, as amended by a Novation Agreement dated December 22,
               2000 among the Borrower,  the  Administrative  Agent on behalf of
               the Lenders, KS Finance and Nicodama,  and as such agreement will
               be further amended pursuant to an Amending and Novation Agreement
               to be  effective  December  31, 2002 and to be entered into among
               the Borrower,  the Administrative Agent on behalf of the Lenders,
               Nicodama and Keyspan  Luxembourg  pursuant to which: (i) the Term
               Loan  Agreement  (as  defined  therein) is amended to reflect the
               consolidation of certain debts owing by the Borrower to Nicodama;
               and  (ii)  the  transfer  of the  Subordinated  Indebtedness  (as
               defined therein) by Nicodama to Keyspan  Luxembourg is reflected,
               in each case  through a series of  transactions  described in the
               last paragraph of the definition of "KS Finance Loan.";

     (o)  replacing the reference to  "Cdn.$100,000,000"  in paragraph  (a.1) of
          the definition of "Permitted Indebtedness" with "Cdn.$106,679,064.21";


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<PAGE>


     (p)  adding the following  definition  immediately  after the definition of
          "Subsidiary":

               ""Synthetic  Lease  Obligations"  means,  as to any  Person,  the
               obligations of such Person to pay rent or other amounts under any
               lease of (or other  arrangement  conveying the right to use) real
               or personal property,  or a combination  thereof,  so long as (i)
               such obligations are not Capital Lease Obligations,  and (ii) the
               asset subject to such lease is a depreciable asset of such Person
               for U.S.  federal  income  tax  purposes;  for  purposes  of this
               Agreement,  the amount of such  obligations  at any time shall be
               determined  by  calculating  the  purchase  price  that  would be
               required  to be paid  by  such  Person  if  such  Person  were to
               exercise  its option to purchase  such asset under such  lease.";
               and

     (q)  adding the following  definition  immediately  after the definition of
          "Termination Event":

               ""Termout  Premium" means, at any time, a rate per annum equal to
               15 bps.".

3.         Other Amendments to the Credit Agreement

           Effective as of December 31, 2002:

          (a)  Section 1.4 of the Credit  Agreement  is amended by deleting  the
               word  "Wherever"  from the first line thereof and replacing  that
               word  with the  words  "Except  as  otherwise  set  forth in this
               Agreement, wherever";

          (b)  Sections  5.1 to 5.3,  inclusive,  of the  Credit  Agreement  are
               deleted in their entirety and replaced with the following:

               "5.1 Interest on Canadian Prime Rate Loans

               The Borrower  shall pay interest on each Canadian Prime Rate Loan
               during  each  Interest  Period  applicable  thereto  in  Canadian
               Dollars at a rate per annum, calculated on the basis of a 365 day
               year,  equal to the  Canadian  Prime Rate in effect  from time to
               time during such Interest  Period plus the Applicable  Prime Rate
               Margin and (in  respect of  Canadian  Prime Rate Loans  which are
               outstanding  on and  after  the date (in this  Section  5.1,  the
               "Termout  Premium  Effective  Date") that is the later of (i) the
               Term Date in respect of the  Commitments  pursuant to which those
               Canadian  Prime Rate Loans were made, and (ii) December 31, 2002)
               the Termout  Premium.  Such interest shall accrue daily and shall
               be payable in arrears on each Interest Payment Date for such Loan
               for the period from and including (i) in the case of the Canadian


                                       9
<PAGE>


               Prime Rate and the  Applicable  Prime Rate  Margin,  the Drawdown
               Date or the preceding  Conversion Date or Interest  Payment Date,
               as the case may be,  for such  Loan,  and (ii) in the case of the
               Termout  Premium,  the  date  that is the  later  of the  Termout
               Premium  Effective  Date and the Drawdown  Date or the  preceding
               Conversion Date or Interest Payment Date, as the case may be, for
               such Loan; in all cases to and  including the day preceding  such
               Interest  Payment Date and shall be  calculated  on the principal
               amount of the Canadian  Prime Rate Loan  outstanding  during such
               period and on the basis of the actual number of days elapsed in a
               year of 365  days.  Changes  in the  Canadian  Prime  Rate or the
               Applicable  Prime  Rate  Margin,   or  the  commencement  of  the
               application  of the Termout  Premium,  shall  cause an  immediate
               adjustment of the interest  rate  applicable to such Loan without
               the necessity of any notice to the Borrower.

               5.2 Interest on U.S. Base Rate Loans

               The  Borrower  shall pay  interest  on each  U.S.  Base Rate Loan
               during each Interest Period  applicable  thereto in United States
               Dollars at a rate per annum, calculated on the basis of a 365 day
               year,  equal to the U.S.  Base Rate in  effect  from time to time
               during such Interest  Period plus the Applicable  USBR Margin and
               (in respect of U.S. Base Rate Loans which are  outstanding on and
               after  the  date (in  this  Section  5.2,  the  "Termout  Premium
               Effective  Date")  that  is the  later  of (i) the  Term  Date in
               respect of the Commitments pursuant to which those U.S. Base Rate
               Loans were made, and (ii) December 31, 2002) the Termout Premium.
               Such interest  shall accrue daily and shall be payable in arrears
               on each  Interest  Payment Date for such Loan for the period from
               and  including  (i) in the  case of the  U.S.  Base  Rate and the
               Applicable  USBR  Margin,  the  Drawdown  Date  or the  preceding
               Conversion Date or Interest Payment Date, as the case may be, for
               such Loan, and (ii) in the case of the Termout Premium,  the date
               that is the later of the Termout  Premium  Effective Date and the
               Drawdown  Date  or the  preceding  Conversion  Date  or  Interest
               Payment  Date, as the case may be, for such Loan; in all cases to
               and including the day  preceding  such Interest  Payment Date and
               shall be calculated on the principal amount of the U.S. Base Rate
               Loan  outstanding  during  such  period  and on the  basis of the
               actual  number of days elapsed in a year of 365 days.  Changes in
               the  U.S.  Base  Rate  or  the  Applicable  USBR  Margin,  or the
               commencement  of the  application of the Termout  Premium,  shall
               cause an immediate  adjustment of the interest rate applicable to
               such Loan without the necessity of any notice to the Borrower.


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<PAGE>


               5.3 Interest on LIBOR Loans

               The  Borrower  shall pay  interest on each LIBOR Loan during each
               Interest Period applicable  thereto in United States Dollars at a
               rate per annum,  calculated on the basis of a 360 day year, equal
               to the LIBOR Rate with respect to such  Interest  Period plus the
               Applicable  LIBOR Margin and (in respect of LIBOR Loans which are
               outstanding  on and  after  the date (in this  Section  5.3,  the
               "Termout  Premium  Effective  Date") that is the later of (i) the
               Term Date in respect of the  Commitments  pursuant to which those
               LIBOR Loans were made,  and (ii)  December  31, 2002) the Termout
               Premium. Such interest shall accrue daily and shall be payable in
               arrears  on each  Interest  Payment  Date for  such  Loan for the
               period from and  including  (i) in the case of the LIBOR Rate and
               the Applicable  LIBOR Margin,  the Drawdown Date or the preceding
               Rollover Date,  Conversion Date or Interest  Payment Date, as the
               case may be, for such Loan,  and (ii) in the case of the  Termout
               Premium,  the  date  that is the  later  of the  Termout  Premium
               Effective Date and the Drawdown Date or the preceding  Conversion
               Date or Interest Payment Date, as the case may be, for such Loan;
               in all cases to and  including  the day  preceding  such Interest
               Payment Date and shall be calculated  on the principal  amount of
               the LIBOR Loan outstanding during such period and on the basis of
               the actual number of days elapsed in a year of 360 days.  Changes
               in  the  LIBOR  Rate  or  the  Applicable  LIBOR  Margin,  or the
               commencement  of the  application of the Termout  Premium,  shall
               cause an immediate  adjustment of the interest rate applicable to
               such Loan without the necessity of any notice to the Borrower.";

     (c)  Section  5.11 of the Credit  Agreement  is amended by adding the words
          and  figures  ", the  Termout  Premium"  immediately  after  the words
          "Applicable BA Fee Rate" in the third line thereof;

     (d)  Section 6.2 of the Credit  Agreement  is deleted in its  entirety  and
          replaced with the following:

               "6.2 Fees

               Upon the  acceptance  by a Lender of a Bankers'  Acceptance,  the
               Borrower shall pay to the Administrative Agent for the account of
               such  Lender a fee in  Canadian  Dollars  equal to the sum of the
               Applicable  BA Fee Rate and (in respect of  Bankers'  Acceptances


                                       11
<PAGE>


               which are outstanding on and after the date (in this Section 6.2,
               the "Termout  Premium  Effective  Date") that is the later of (i)
               the Term Date in respect  of the  Commitments  pursuant  to which
               those Bankers'  Acceptances were accepted,  and (ii) December 31,
               2002) the Termout Premium,  calculated on the principal amount at
               maturity of such Bankers'  Acceptance  and for the period of time
               from and including (i) in the case of the Applicable BA Fee Rate,
               the  date of  acceptance,  and  (ii) in the  case of the  Termout
               Premium,  the  date  that is the  later  of the  Termout  Premium
               Effective  Date and the date of  acceptance;  in all cases to but
               excluding  the  maturity  date of such  Bankers'  Acceptance  and
               calculated on the basis of the actual number of days elapsed in a
               year of 365 days.";

     (e)  Section 8.1(n) of the Credit  Agreement is deleted in its entirety and
          replaced with the following:

               "Debt - The  Borrower  has no  indebtedness  for  borrowed  money
               except  (i) the  amount of up to  $105,058,379.58  plus  interest
               accrued  thereon since January 1, 2001 owing to Nicodama or (once
               the  transactions  referred  to in  the  last  paragraph  of  the
               definition  of "KS  Finance  Loan" have been  completed)  Keyspan
               Luxembourg  pursuant to the KS Finance Loan, (ii) indebtedness of
               up to Cdn.$125,000,000  pursuant to the credit agreement dated as
               of October  13,  2000 among the  Borrower  as  Borrower,  Bank of
               Montreal and the other financial  institutions named therein from
               time to time as lenders  and Bank of  Montreal as agent for those
               lenders,  (iii)  indebtedness  in the  principal  amount of up to
               Cdn.$106,679,064.21  and interest  thereon since January 1, 2001,
               pursuant to the KS Luxembourg  Credit  Agreement (as that term is
               defined in the Keyspan Luxembourg  Subordination  Agreement),  as
               such credit  agreement is to be replaced by a  Consolidated  Loan
               Agreement  between  the  Borrower  and Keyspan  Luxembourg  and a
               Consolidated  Promissory  Note granted by the Borrower to Keyspan
               Luxembourg both to be effective December 31, 2002, and (iv) other
               indebtedness  permitted  hereunder  or consented to in writing by
               the Administrative Agent.";

     (f)  Section 10.1(r)(i) of the Credit Agreement is amended by replacing the
          numbers and figures "0.65:1" with "0.66:1";

     (g)  Section  14.10(a)(ii) of the Credit Agreement is amended by adding the
          words and figures ", the Termout Premium"  immediately after the words
          "Applicable Margin" in the first line thereof; and

     (h)  the end of the current  Revolving  Period is hereby  deemed to be July
          23, 2003.


                                       12
<PAGE>


4.          Consent

     To the extent their consent is required,  the Administrative  Agent and the
Lenders hereby consent to the Intercorporate  Debt Transactions for all purposes
under the Amended Credit Agreement,  and all documents and agreements incidental
thereto,  including without limitation the Nicodama Subordination  Agreement and
the Keyspan Luxembourg Subordination Agreement.

5.         Conditions Precedent

     The amendments to the Credit  Agreement set forth in paragraphs  2(a), (b),
(c), (m) and (q) and 3(b), (c), (d) and (h) of this Third Amending Agreement are
unconditional  and  shall be  effective  as of  December  31,  2002.  The  other
amendments to the Credit  Agreement set forth in Section 2 and Section 3 of this
Third Amending  Agreement,  and the consent set forth in Section 4 of this Third
Amending Agreement,  shall not be effective unless the following conditions have
been fulfilled to the satisfaction of the Administrative Agent:

     (a)  the  Administrative  Agent shall have  received  from the  Guarantor a
          confirmation  of the Guarantee in form and substance  satisfactory  to
          the  Administrative  Agent  regarding  the  amendments  to the  Credit
          Agreement set forth in this Third Amending Agreement;

     (b)  no Default or Event of Default shall have occurred and be  continuing,
          and the  Administrative  Agent shall have received a certificate of an
          officer of the Borrower to that effect; and

     (c)  the Borrower shall have paid to the Agent for the rateable  benefit of
          the Lenders an amount equal to 10 bps on the aggregate  Commitments of
          all of the Lenders.

     The  Administrative  Agent shall forthwith  advise the Borrower when all of
the foregoing conditions in this Section 5 have been satisfied.

6.        Provisions Regarding Intercorporate Debt Transactions

     (a)  The Borrower  represents and warrants that it expects the transactions
          referred to in paragraphs 1 through 6 of Exhibit A hereto to have been
          completed on or before December 31, 2002.

     (b)  The Borrower covenants and agrees to execute and deliver, and to cause
          Keyspan Luxembourg to execute and deliver, to the Administrative Agent
          on  behalf  of the  Lenders,  an  amending  agreement  (the  "Amending
          Agreement") substantially in the form attached hereto as Exhibit B, in
          respect of the Keyspan Luxembourg Subordination Agreement which amends
          the definition of "KS Luxembourg  Credit  Agreement"  therein so as to


                                       13
<PAGE>


          accommodate  certain changes to the KS Luxembourg  Credit Agreement as
          set forth in the Amending  Agreement.  The Borrower  acknowledges  and
          agrees that:

          (i)  it will  execute and deliver,  and cause  Keyspan  Luxembourg  to
               execute and deliver, the Amending Agreement to the Administrative
               Agent on behalf of the Lenders  forthwith upon  completion of the
               transactions referred to in paragraph 7 of Exhibit A hereto; and

          (ii) if the Borrower fails to comply with its obligations in paragraph
               (i) above,  then such  failure  shall be deemed to be an Event of
               Default under the Amended Credit Agreement.

     (c)  The Borrower covenants and agrees to execute and deliver, and to cause
          Nicodama to execute and deliver, to the Administrative Agent on behalf
          of the Lenders an amending and novation  agreement  (the "Amending and
          Novation  Agreement")  substantially  in the form  attached  hereto as
          Exhibit C, in respect of the Nicodama  Subordination  Agreement  which
          amends  the  definition  of "Term  Loan  Agreement"  therein  so as to
          accommodate  certain  changes to the Term Loan Agreement and to novate
          Keyspan Luxembourg into the Nicodama Subordination  Agreement,  all as
          set  forth  in the  Amending  and  Novation  Agreement.  The  Borrower
          acknowledges and agrees that:

          (i)  it will  execute  and  deliver,  and cause  Nicodama  and Keyspan
               Luxembourg  to execute and  deliver,  such  Amending and Novation
               Agreement  to the  Administrative  Agent on behalf of the Lenders
               forthwith upon completion of all of the transactions  referred to
               in paragraphs 8 and 9 of Exhibit A hereto; and

          (ii) if the Borrower fails to comply with its obligations in paragraph
               (i) above,  then such  failure  shall be deemed to be an Event of
               Default under the Amended Credit Agreement.

7.        Representations and Warranties

     The  Borrower  hereby  represents  and  warrants  to the  Lenders  that the
applicable representations and warranties contained in Section 8.1 of the Credit
Agreement are true and accurate in all material  respects as if made on the date
of this Third Amending Agreement.

8.         Confirmation

     Each  of the  parties  hereto  acknowledges  and  agrees  that  the  Credit
Agreement, as amended by this Third Amending Agreement,  and all other Documents


                                       14
<PAGE>

are and will  continue to be in full force and effect,  and are hereby  ratified
and confirmed, and the rights and obligations of all parties thereunder will not
be affected in any manner by the  provisions of this Third  Amending  Agreement,
except as expressly  provided in Section 2 and Section 3 of this Third  Amending
Agreement.

9.         Further Assurances

     The Borrower will from time to time  forthwith,  and at the  Borrower's own
cost and expense,  do, make,  execute and  deliver,  or cause to be done,  made,
executed  and  delivered,  all such  further  documents,  financing  statements,
assignments,  acts,  manners and things which may be reasonably  required by the
Administrative Agent and are consistent with the intention of the parties hereto
as  evidenced  herein,  with  respect to all  matters  arising  under this Third
Amending Agreement or the Amended Credit Agreement.

10.        Expenses

     Without in any way  limiting the  provisions  of Section 12.1 of the Credit
Agreement,  the  Borrower  will be liable  for all  reasonable  expenses  of the
Administrative  Agent  and the  Lenders,  including  legal  fees,  the  fees and
expenses  of the  Administrative  Agent and  other  out-of-pocket  expenses,  in
connection  with the  negotiation,  preparation,  execution and delivery of this
Third Amending Agreement.



















                                       15
<PAGE>



11.  Counterparts

     This  Third   Amending   Agreement   may  be  executed  in  any  number  of
counterparts,  each of which when executed and delivered will be deemed to be an
original, and all of which when taken together shall constitute one and the same
instrument.

     IN WITNESS  WHEREOF  the parties  hereto  have  caused this Third  Amending
Agreement to be duly executed by their respective  authorized officers as of the
date and year first above written.

                                 KEYSPAN ENERGY DEVELOPMENT CO.,
                                 as Borrower


                                 Per:
                                     -------------------------------------------
                                     Name:
                                     Title:


                                 Per:
                                     -------------------------------------------
                                     Name:
                                     Title:


                                 ROYAL BANK OF CANADA, in its capacity
                                 as Administrative Agent


                                 Per:
                                     -------------------------------------------
                                     Name:
                                     Title:


                                 Per:
                                     -------------------------------------------
                                     Name:
                                     Title:






                                       16
<PAGE>




                                      ROYAL BANK OF CANADA, as a Lender


                                      Per:
                                          --------------------------------------
                                          Name:
                                          Title:


                                      Per:
                                          --------------------------------------
                                          Name:
                                          Title:















This page is attached to and forms part of a Third Amending  Agreement  dated as
of December 20, 2002 among Keyspan  Energy  Development  Co. as Borrower,  Royal
Bank of Canada, JPMorgan Chase Bank, Toronto Branch, Bank of Montreal, Bank One,
National Association, Canada Branch and Alberta Treasury Branches as Lenders and
Royal Bank of Canada as Administrative Agent.




                                       17
<PAGE>







                                           JPMORGAN CHASE BANK, TORONTO
                                           BRANCH, as a Lender


                                           Per:
                                               ---------------------------------
                                               Name:
                                               Title:


                                           Per:
                                               ---------------------------------
                                               Name:
                                               Title:



















This page is attached to and forms part of a Third Amending Agreement dated as
of December 20, 2002 among Keyspan Energy Development Co. as Borrower, Royal
Bank of Canada, JPMorgan Chase Bank, Toronto Branch, Bank of Montreal, Bank One,
National Association, Canada Branch and Alberta Treasury Branches as Lenders and
Royal Bank of Canada as Administrative Agent.




                                       18
<PAGE>






                                              BANK OF MONTREAL, as a Lender


                                              Per:
                                                  ------------------------------
                                                  Name:
                                                  Title:
                                              Per:
                                                  ------------------------------
                                                  Name:
                                                  Title:


















This page is attached to and forms part of a Third Amending Agreement dated as
of December 20, 2002 among Keyspan Energy Development Co. as Borrower, Royal
Bank of Canada, JPMorgan Chase Bank, Toronto Branch, Bank of Montreal, Bank One,
National Association, Canada Branch and Alberta Treasury Branches as Lenders and
Royal Bank of Canada as Administrative Agent.





                                       19
<PAGE>





                                             BANK ONE, NATIONAL
                                             ASSOCIATION, CANADA BRANCH, as
                                             a Lender


                                             Per:
                                                --------------------------------
                                                Name:
                                                Title:
                                             Per:
                                                --------------------------------
                                                Name:
                                                Title:























This page is attached to and forms part of a Third Amending Agreement dated as
of December 20, 2002 among Keyspan Energy Development Co. as Borrower, Royal
Bank of Canada, JPMorgan Chase Bank, Toronto Branch, Bank of Montreal, Bank One,
National Association, Canada Branch and Alberta Treasury Branches as Lenders and
Royal Bank of Canada as Administrative Agent.




                                       20
<PAGE>






                                              ALBERTA TREASURY BRANCHES, as a
                                              Lender


                                              Per:
                                                 -------------------------------
                                                 Name:
                                                 Title:
                                              Per:
                                                 -------------------------------
                                                 Name:
                                                 Title:
























This page is attached to and forms part of a Third Amending Agreement dated as
of December 20, 2002 among Keyspan Energy Development Co. as Borrower, Royal
Bank of Canada, JPMorgan Chase Bank, Toronto Branch, Bank of Montreal, Bank One,
National Association, Canada Branch and Alberta Treasury Branches as Lenders and
Royal Bank of Canada as Administrative Agent.




                                       21
<PAGE>



EXHIBIT A to the Third  Amending  Agreement  dated as of December 20, 2002 among
Keyspan  Energy  Development  Co., as Borrower,  Royal Bank of Canada,  JPMorgan
Chase Bank, Toronto Branch,  Bank Of Montreal,  Bank One, National  Association,
Canada  Branch and Alberta  Treasury  Branches,  as  Lenders,  and Royal Bank of
Canada, as Administrative Agent

Intercorporate Debt Transactions (1)

1.   Nicodama  loaned  $5,308,677.44  to the Borrower on June 1, 2000 ("Nicodama
     Loan #2").

2.   The Borrower pays interest of $709,357.92  to Keyspan  Luxembourg on the KS
     Luxembourg  Loan,  as  that  term  is  defined  in the  Keyspan  Luxembourg
     Subordination  Agreement,  deducting 10 percent of the interest payment for
     remittance to the Canada Customs and Revenue Agency ("CCRA").

3.   The Borrower  makes a repayment of principal in the amount of $70,935.79 on
     the KS  Luxembourg  Loan  (leaving a principal  amount  remaining on the KS
     Luxembourg Loan of $99,929,064.21).

4.   The Borrower pays interest of  $7,621,378.56  to Nicodama on the KS Finance
     Loan and Nicodama Loan #2, deducting 10 percent of the interest payment for
     remittance to the CCRA.

5.   The Borrower makes a repayment of principal in the amount of $762,137.86 on
     the KS Finance Loan (leaving a principal amount remaining on the KS Finance
     Loan of $99,749,702.14).

6.   Keyspan  Luxembourg loans the Borrower  $6,750,000.00  ("KS Luxembourg Loan
     #2") on terms identical to the KS Luxembourg Loan.

7.   Keyspan Luxembourg and the Borrower  consolidate the KS Luxembourg Loan (of
     which $99,929,064.21 is outstanding) and the KS Luxembourg Loan #2, issuing
     a  Consolidated  Promissory  Note and  entering  into a  Consolidated  Loan
     Agreement  which  requires  Keyspan  Luxembourg to loan future  payments of
     accrued  interest  back to the  Borrower  and allows the Borrower to re-pay
     principal before accrued interest.

8.   Nicodama  and the  Borrower  consolidate  the KS  Finance  Loan  (of  which
     $99,749,702.14  is outstanding)  and Nicodama Loan #2, issuing a Promissory
     Note and a Consolidated  Loan Agreement  which restates the loan principal,
     provides  for  interest  calculation  and  allows  the  Borrower  to re-pay
     principal before accrued interest.

9.   Nicodama   transfers  the  Nicodama   Promissory   Note  and  the  Nicodama
     Consolidated  Loan  Agreement to Keyspan  Luxembourg  as payment of certain
     amounts owing by Nicodama to Keyspan Luxembourg.
--------
(1) Amounts referenced herein are stated in Canadian dollars.


<PAGE>


EXHIBIT B to the Third  Amending  Agreement  dated as of December 20, 2002 among
Keyspan  Energy  Development  Co., as Borrower,  Royal Bank of Canada,  JPMorgan
Chase Bank, Toronto Branch,  Bank of Montreal,  Bank One, National  Association,
Canada  Branch and Alberta  Treasury  Branches,  as  Lenders,  and Royal Bank of
Canada, as Administrative Agent



                               Amending Agreement




























<PAGE>


EXHIBIT C to the Third  Amending  Agreement  dated as of December 20, 2002 among
Keyspan  Energy  Development  Co., as Borrower,  Royal Bank of Canada,  JPMorgan
Chase Bank, Toronto Branch,  Bank of Montreal,  Bank One, National  Association,
Canada  Branch and Alberta  Treasury  Branches,  as  Lenders,  and Royal Bank of
Canada, as Administrative Agent



                         Amending and Novation Agreement