EXHIBIT 10.25d


                          INSTRUMENT OF ASSIGNMENT AND
                           ASSUMPTION OF NON-EMPLOYEE
                           DIRECTORS COMMON STOCK AND
                           DEFERRED COMPENSATION PLAN

         THIS INSTRUMENT (the "Assignment and Assumption Agreement"), made as of
the 21st day of July, 2000, by and between The United  Illuminating  company,  a
Connecticut  corporation  (the  "Assignor"),  and UIL  Holdings  Corporation,  a
Connecticut corporation (the "Assignee").

                               WITNESSETH THAT:

         WHEREAS,  effective  at the close of  business  on July 20,  2000,  and
pursuant  to an  Agreement  and Plan of Merger and Share  Exchange,  dated as of
January 24, 2000, among Assignor,  Assignee and United Mergings,  Inc., Assignor
became a  wholly-owned  subsidiary of Assignee,  and each  outstanding  share of
Assignor's Common Stock was  automatically  converted into and exchanged for one
share of Assignee's Common Stock; and

         WHEREAS,  effective  at the close of  business on July 20,  2000,  each
non-employee Director of Assignor was duly elected a Director of Assignee; and

         WHEREAS,  Assignor  has  had  in  effect  since  December  22,  1980  a
compensation  plan for its  non-employee  Directors,  which plan, as amended and
restated on July 23, 1990,  December 17, 1990, May 15, 1996,  December 13, 1999,
and as of the close of business on July 20,  2000,  has provided for the payment
to  non-employee  Directors  of Assignor of portions of their  compensation  for
service as  Directors  in shares of  Assignor's  Common  Stock,  and has allowed
non-employee  Directors  of  Assignor  to defer the  payment of part of the fees
payable  to them for  service as  Directors  of  Assignor,  all as set forth and
described in said Non-Employee  Directors Common Stock and Deferred Compensation
Plan, as amended and restated (the "Plan"); and

         WHEREAS,  the Plan,  as  amended by said  amendment  as of the close of
business on July 20, 2000, has become the Plan of Assignee; and

         WHEREAS, Assignor desires to assign and Assignee desires to assume, all
of  Assignor's  right and  interest  in and to, and all of the  obligations  and
liabilities arising out of the Plan,


         NOW THEREFORE, in consideration of the premises,  Assignor and Assignee
hereby agree as follows:

     1.  Assignor  assigns,  transfers  and delivers to  Assignee,  and Assignee
hereby assumes,  all of Assignor's  right and interest in and to, and all of the
obligations and liabilities arising out of, the Plan.


<PAGE>

     2.  Assignee  assumes and agrees to perform  all of the terms,  conditions,
covenants and agreements of the Plan on the part of the Company (as that term is
defined in the Plan) thereunder,  including, without limitation, all obligations
of Assignor to individuals  who have served as Directors of Assignor at any time
since December 22, 1980, and to their beneficiaries, spouses, legal guardians or
conservators;  and  Assignee  does hereby  covenant  and agree to hold  harmless
Assignor  from and against  any  claims,  demands,  suits,  actions,  damages or
expenses, including but not limited to attorneys' fees, arising out of or in any
way  connected  with any  default or alleged  default on the part of Assignee in
faithful  performance  of  the  terms,  conditions,   covenants  and  agreements
contained in the Plan.

     3. This  Assignment  and  Assumption  Agreement  may not be modified in any
manner or terminated, except by an instrument in writing executed by the parties
hereto.

     4. This  Assignment  and  Assumption  Agreement  shall be  governed  by and
construed in accordance with the laws of the State of Connecticut.


         IN WITNESS  WHEREOF,  the  parties  have  caused  this  Assignment  and
Assumption Agreement to be executed as of the day and year first written above.

ASSIGNOR:
THE UNITED ILLUMINATING COMPANY


By:  /s/ Robert L. Fiscus
     ------------------------------------------------
      Robert L. Fiscus
      Its:  Vice Chairman of the Board of Directors
            and Chief Financial Officer



And by:  /s/ Charles J. Pepe
         --------------------------------------------
           Charles J. Pepe
           Its:  Treasurer


ASSIGNEE:
UIL HOLDINGS CORPORATION



By:  /s/Robert L. Fiscus
     ------------------------------------------------
      Robert L. Fiscus
      Its:  Vice Chairman of the Board of Directors
            Chief Financial Officer, Treasurer and
            Secretary

                                        2