SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM 8-A/A


                         ------------------------------



                FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES

                     PURSUANT TO SECTION 12(b) OR (g) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                                 AMENDMENT NO. 1



                               TRENWICK GROUP INC.
 -------------------------------------------------------------------------------

             (Exact name of registrant as specified in its charter)



         Delaware                     0-14737                    06-1152790
 --------------------------     --------------------      ----------------------
(State of incorporation        (Commission File Number)     (I.R.S. Employer
 or organization)                                            Identification No.)

One Canterbury Green, Stamford, Connecticut                      06901
- -------------------------------------------             ------------------------
  (Address of principal executive offices)                    (Zip Code)


Registrant's telephone number, including area code:  203-353-5500

Securities to be registered pursuant to Section 12(b) of the Act:

         Title of each class                      Name of each exchange on which
         to be so registered                      each class is to be registered

Preferred Stock Purchase Rights                   New York Stock Exchange





                               Page 1 of 8 pages





Item 1.   Amendment to Description of Registrant's Securities to be Registered
          --------------------------------------------------------------------
         The Form 8-A, filed  September 25, 1997, of Trenwick  Group Inc. (the
"Company")  is hereby  amended  by  adding  the  following  at the end of Item 1
thereof:

         On December 19, 1999,  the Company and First  Chicago Trust Company  of
New York, as rights agent,  entered into Amendment No.1 (the "Amendment") to the
Rights Agreement.  The Amendment provides that the execution and delivery by the
Company  of the  Agreement,  Scheme of  Arrangement,  Plan of Merger and Plan of
Reorganization,  dated  as of  December  19,  1999  (the  "Business  Combination
Agreement"),  the Stock Option  Agreements,  each dated as of December 19, 1999,
and  the  Shareholders  Agreement,  dated  as of  December  19,  1999,  and  the
consummation of the transactions contemplated by such agreements, will not cause
(i) any of the other  parties to the  Business  Combination  Agreement  or their
respective  affiliates or associates  to be deemed an Acquiring  Person,  (ii) a
Distribution  Date (as  defined in the Rights  Agreement)  to occur,  or (iii) a
Triggering  Event (as defined in the Rights  Agreement) to occur.  The Amendment
also provides that the Rights  Agreement  will expire  immediately  prior to the
consummation  of  the  transactions  contemplated  by the  Business  Combination
Agreement.

         On September 25, 1997 the Company filed a copy of the Rights  Agreement
with the Securities  and Exchange  Commission as Exhibit 1 to the Company's Form
8-A. A copy of the Amendment is filed herewith.  A copy of the Rights  Agreement
and the  Amendment  is available  free of charge from the Company.  This summary
description of the Amendment does not purport to be complete and is qualified in
its entirety by reference to the Amendment.


Item 2.  Exhibits
         --------

1.       Rights  Agreement,  dated as of September  24, 1997,  between  Trenwick
         Group Inc.  and First  Chicago  Trust  Company  of New York,  as Rights
         Agent,  which  includes  as  Exhibit  B  thereto  the  form  of  Rights
         Certificate.   (Incorporated   by   reference   to  Exhibit  1  to  the
         registrant's  registration  statement on Form 8-A filed  September  25,
         1997, File No. 0-14737).

2.       Amendment  No. 1 to Rights Agreement, dated  as  of December  19, 1999,
         between  Trenwick  Group  Inc. and  First  Chicago  Trust  Company  of
         New York, as Rights Agent.





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                                    SIGNATURE


         Pursuant to the  requirements of Section 12 of the Securities  Exchange
Act of 1934, the registrant  has duly caused this  registration  statement to be
signed on its behalf by the undersigned, thereto duly authorized.

                                                     TRENWICK GROUP INC.





                                                  By:  /s/ James F. Billett, Jr
                                                       ------------------------
                                                       James F. Billett, Jr.
                                                       Chairman, President &
                                                       Chief Executive Officer

Dated: January 13, 2000












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                                  EXHIBIT INDEX

Exhibit                    Description of Exhibit
- -------                    ----------------------

    1                      Rights  Agreement,  dated as of  September  24, 1997,
                           between  Trenwick  Group Inc. and First Chicago Trust
                           Company of New York, as Rights Agent,  which includes
                           as Exhibit B thereto the form of Rights  Certificate.
                           (Incorporated  by  reference  to  Exhibit  1  to  the
                           registrant's registration statement on Form 8-A filed
                           September 25, 1997, File No. 0-14737).

    2                      Amendment  No. 1 to  Rights  Agreement, dated  as  of
                           December 19, 1999,  between  Trenwick  Group Inc. and
                           First  Chicago  Trust Company of  New York, as Rights
                           Agent.




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