Exhibit 99.4

                    NINTH AMENDMENT TO THE HOLDINGS GUARANTY

            NINTH AMENDMENT TO THE HOLDINGS GUARANTY (the "Ninth Amendment"),
dated as of March 28, 2003, among TRENWICK GROUP LTD., a company organized under
the laws of Bermuda ("Holdings") and the Banks party to the Credit Agreement
referred to below. Unless otherwise defined herein, capitalized terms used
herein and defined in the Holdings Guaranty referred to below are used herein as
so defined.

                              W I T N E S S E T H :

            WHEREAS, Trenwick America Corporation, a Delaware corporation (the
"Borrower"), Trenwick Holdings Ltd., a company organized under the laws of the
United Kingdom (the "Trenwick Holdings"), the lending institutions from time to
time party thereto (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"), 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, 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
parties hereto wish to amend the Holdings Guaranty as provided herein;

            NOW, THEREFORE, it is agreed;

A.    Amendments

            1. Section 3.13(b) of the Holdings Guaranty is hereby amended by
deleting the text "March 27, 2003" appearing therein and inserting the text
"11:00 P.M. (New York time) on March 31, 2003" in lieu thereof.



            2. Section 3.14 of the Holdings Guaranty is hereby amended by
deleting the text "March 27, 2003" appearing therein and inserting the text
"11:00 P.M. (New York time) on March 31, 2003" in lieu thereof.

            3. Section 3.15 of the Holdings Guaranty is hereby amended by
deleting the text "March 27, 2003" appearing therein and inserting the text
"11:00 P.M. (New York time) on March 31, 2003" in lieu thereof.

            4. Section 3.16 of the Holdings Guaranty is hereby amended by
deleting the text "March 27, 2003" appearing therein and inserting the text
"11:00 P.M. (New York time) on March 31, 2003" in lieu thereof.

            5. Section 3.18 of the Holdings Guaranty is hereby amended by
deleting the text "March 28, 2003" appearing therein and inserting the text
"April 4, 2003" in lieu thereof.

            6. Section 4.23 of the Holdings Guaranty is hereby amended by
deleting the text ", provided that the payments of any bonus or compensation
other than salary or monthly fees under the Specified Employment Agreements and
the Unallocated Additional Fee Agreements may only be made if (I) no Default or
Event of Default then exists at the time of such payment or would result
therefrom and (II) if any Default or Event of Default has occurred (A) the
Required Banks have consented to permit such payments after such Default or
Event of Default has been cured or waived or (B) the Banks consent to such
payments notwithstanding that an Event of Default has occurred and is
continuing" appearing therein.

            7. Schedule I to the Holdings Guaranty is hereby amended by (x)
deleting the text "(i) a non-solicitation clause on terms reasonably
satisfactory to the Administrative Agent and (ii)" and (y) inserting the text
"(except for any terms and conditions that restrict any payment in such
Agreement to the extent that there is a Default or Event of Default at the time
of such payment or as a result thereof)" immediately following the text
"Executive Compensation Provisions", in each case in the definitions of "Binet
Employment Agreement", "Becker Agreement", "Finkelstein Agreement", "Giordano
Employment Agreement", "Graham Agreement", "Hunte Employment Agreement",
"Semeraro Employment Agreement" and "Watson Employment Agreement".

B.    Miscellaneous Provisions

            1. In order to induce the Banks to enter into this Ninth Amendment,
Holdings hereby represents and warrants that (i) the representations and
warranties of Holdings contained in the Holdings Guaranty are true and correct
in all material respects on and as of the Ninth 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 Ninth Amendment Effective
Date (as defined below), in each case after giving effect to this Ninth
Amendment.

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


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            3. THIS NINTH 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.

            4. This Ninth Amendment shall become effective on the date (the
"Ninth Amendment Effective Date") when Holdings 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.

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

                                      * * *


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

                                              TRENWICK GROUP LTD.


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



                                              [NAME OF LENDER]


                                              By:
                                                 ------------------------------
                                                 Name:
                                                 Title:

        [Signature Page to the Ninth Amendment to the Holdings Guaranty]