EXHIBIT 99.1

                     FIFTH AMENDMENT TO THE CREDIT AGREEMENT

      FIFTH AMENDMENT TO THE CREDIT AGREEMENT (the "Fifth Amendment"), dated as
of January 16, 2003, among TRENWICK AMERICA CORPORATION, a Delaware corporation
(the "Borrower"), TRENWICK HOLDINGS LIMITED., a company organized under the laws
of the United Kingdom and TRENWICK UK HOLDINGS LIMITED, a company organized
under the laws of the United Kingdom (collectively, the "Account Party"), the
lending institutions from time to time party to the Credit Agreement referred to
below (each a "Bank" and, collectively, the "Banks"), WACHOVIA BANK, NATIONAL
ASSOCIATION (f/k/a First Union National Bank), as Syndication Agent (the
"Syndication Agent"), FLEET NATIONAL BANK, as Documentation Agent (the
"Documentation Agent"), and JPMORGAN CHASE BANK (f/k/a The Chase Manhattan
Bank), as Administrative Agent (the "Administrative Agent"). Unless otherwise
defined herein, capitalized terms used herein and defined in the Credit
Agreement referred to below are used herein as so defined.

                              W I T N E S S E T H :

      WHEREAS, the Borrower, the Account Party, the Banks, the Syndication
Agent, the Documentation Agent and the Administrative Agent are party to a
Credit Agreement, dated as of November 24, 1999 and amended and restated as of
September 27, 2000 (as the same has been amended, modified or supplemented to,
but not including, the date hereof, the "Credit Agreement");

      WHEREAS, the Trenwick Group Ltd., a company organized under the laws of
Bermuda ("Holdings") and the Administrative Agent entered into a Holdings
Guaranty, dated as of September 27, 2000 (as the same has been amended, modified
or supplemented to, but not including, the date hereof, the "Holdings Guaranty")
in order to induce the Banks to make Loans to the Borrower and issue Letters of
Credit for the account of the Account Party and Guaranteed Creditors (and
Lending Affiliates thereof) to enter into Interest Rate Protection Agreements
and Other Hedging Agreements with the Borrower and/or the Account Party; and

      WHEREAS, subject to the terms and conditions set forth below, the Banks
hereto wish to grant amendments to the Credit Agreement as provided herein;

      NOW, THEREFORE, it is agreed;

A.    Amendments

      1. The definition of "Specified Expenditures" appearing in Schedule I to
the Credit Agreement is hereby amended by (i) deleting the word "and" appearing
immediately before clause (xiv) thereof and inserting a comma in lieu thereof
and (ii) inserting the following new clauses (xv) and (xvi) immediately after
the end of clause (xiv) thereof:





            ", (xv) fees and expenses incurred for restructuring advisors and
      legal counsel retained by Holdings in connection with the restructuring
      and/or reorganization of Holdings and its Subsidiaries, and (xvi) fees and
      expenses incurred for reserve studies and actuarial services in connection
      with the evaluation of loss reserves of any applicable Subsidiary of
      Holdings".

      2. The definition of "Statutory Surplus" appearing in Schedule I to the
Credit Agreement is hereby amended by deleting the text "line 27," appearing in
said definition and inserting the text "the line captioned "Surplus As Regards
Policyholders" appearing on" in lieu thereof.

      3. The definition of "Surplus" appearing in Schedule I to the Credit
Agreement is hereby amended by deleting the text "line 32," appearing in said
definition and inserting the text "the line captioned "Surplus As Regards
Policyholders" appearing on" in lieu thereof.

      4. Schedule I to the Credit Agreement is hereby amended by inserting the
following defined terms in the appropriate alphabetical order:

            "Fifth Amendment" shall mean the Fifth Amendment and Consent to the
      Holdings Guaranty, dated as of January 16, 2003.

            "Fifth Amendment Effective Date" shall have the meaning provided in
      the Fifth Amendment.

            "TARCO" shall have the meaning provided in Section 4.03(f) of the
      Holdings Guaranty.

C.    Miscellaneous Provisions

      1. In order to induce the Banks to enter into this Fifth Amendment, each
of the Borrower and each Account Party hereby represent and warrant on behalf of
themselves and their respective Subsidiaries that (i) the representations and
warranties of contained in Section 2 of the Holdings Guaranty are true and
correct in all material respects on and as of the Fifth Amendment Effective Date
(as defined below) (except with respect to any representations and warranties
limited by their terms to a specific date, which shall be true and correct in
all material respects as of such date), and (ii) there exists no Default or
Event of Default under the Credit Agreement on the Fifth Amendment Effective
Date (other than with respect to Holdings' failure to comply with Section
4.04(g) of the Holdings Guaranty), in each case after giving effect to this
Fifth Amendment.

      2. This Fifth Amendment is limited as specified and shall not constitute
an amendment, modification, acceptance or waiver of any other provision of the
Credit Agreement or any other Credit Document.

      3. THIS FIFTH AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES
HEREUNDER SHALL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAW OF THE
STATE OF NEW YORK.


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      4. This Fifth Amendment shall become effective on the date (the "Fifth
Amendment Effective Date") when each of the following conditions have been
satisfied:

            (i) the Borrower, each Account Party and the Required Banks shall
      have signed a counterpart hereof (whether the same or different
      counterparts) and shall have delivered (including by way of telecopier)
      the same to the Administrative Agent; and

            (ii) Holdings and the Required Banks have signed the Fifth Amendment
      and Consent to the Holdings Guaranty dated as of January 16, 2003 (the
      "Holdings Guaranty Amendment").

      5. From and after the Fifth Amendment Effective Date, all references in
the Credit Agreement and in the other Credit Documents shall be deemed to be
referenced to the Credit Agreement as modified hereby.

                                      * * *


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      IN WITNESS WHEREOF, the undersigned have caused this Third Amendment to be
duly executed and delivered as of the date first above written.

                                        TRENWICK AMERICA CORPORATION

                                        By: /s/ Alan L. Hunte
                                           -------------------------------
                                           Name:  Alan L. Hunte
                                           Title: Executive Vice President
                                                  Chief Financial Officer


                                        TRENWICK HOLDINGS LIMITED

                                        By: /s/ Alan L. Hunte
                                           -------------------------------
                                           Name:  Alan L. Hunte
                                           Title: Director


                                        TRENWICK UK HOLDINGS LIMITED

                                        By: /s/ Alan L. Hunte
                                           -------------------------------
                                           Name:  Alan L. Hunte
                                           Title: Director





                  [Bank Signature Pages Intentionally Omitted]


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