8-K

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                                    FORM 8-K

                                 CURRENT REPORT
                         PURSUANT TO SECTION 13 OR 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

        Date of Report (date of earliest event reported) -April 18, 2003

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

                          TRENWICK AMERICA CORPORATION
             (Exact name of registrant as specified in its charter)

            Delaware                        0-31967               06-1087672
(State or other jurisdiction of    (Commission File Number)     (IRS Employer
         Incorporation)                                      Identification No.)

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

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

                                      None
             (Former name or address, if changed since last report)



Item 5. Other Events.

      Trenwick Group Ltd. ("Trenwick"), entered into Amendment No. 1 to the
Rights Agreement, dated as of April 18, 2003 (the "First Amendment"), with
EquiServe Trust Company, N.A. (successor to First Chicago Trust Company of New
York) (the "Rights Agent") pursuant to which to the Rights Agreement dated as of
September 27, 2000 (the "Rights Agreement") between Trenwick and the Rights
Agent was amended.

      The First Amendment enumerates an additional exclusion from the definition
of "Acquiring Person" under the Rights Agreement. Specifically, it gives the
Board of Directors the authority to determine that a person should be excluded
from the definition of Acquiring Person under the Rights Agreement, provided the
determination is made prior to the time such Person would otherwise become an
Acquiring Person. Generally, under the Rights Agreement, a person becomes an
"Acquiring Person" when such person, together with all affiliates and associates
of such person, is the "Beneficial Owner" of 15% or more of Trenwick's Common
Shares, par value $0.10 per share (the "Common Shares") outstanding. "Beneficial
Ownership" arises under the Rights Agreement when a person has the right to
acquire (whether such right is exercisable immediately or only after the passage
of time) the Common Shares pursuant to any agreement, arrangement or
understanding or upon the exercise of conversion rights, exchange rights,
rights, warrants or options, or otherwise.

      On February 20, 2003, Trenwick delivered a notice to European Reinsurance
Company of Zurich ("European Re") that Trenwick's GAAP Net Worth (as defined in
the Certificate of Designation, Preferences and Rights (the "Certificate of
Designation") of the Series B Cumulative Convertible Perpetual Preferred Shares
(the "Series B Shares")) had fallen below $225 million.

      Trenwick's GAAP Net Worth has not equaled or exceeded $225 million during
the period from February 20, 2003 through April 21, 2003 (which is 60 days after
the date of the notice), as a result, a Net Worth Conversion Event (as defined
in the Certificate of Designation) has occurred on April 21, 2003, and the
Series B Shares are now convertible at the option of European Re into the Common
Shares upon 60 trading days advance notice to Trenwick. European Re has not
delivered to Trenwick such a notice of conversion. In the event of a conversion
of all of the Series B Shares, European Re would become the beneficial owner of
more than 15% of Trenwick's Common Shares outstanding and consequently would be
an Acquiring Person under the Rights Agreement.

      On April 18, 2003, the Board of Directors of Trenwick, in accordance with
the Rights Agreement, as amended by the First Amendment, adopted a resolution
excluding European Re from the definition of Acquiring Person under the Rights
Agreement (the "Exclusion"). The Exclusion only applies to the Beneficial
Ownership (as defined in the Rights Agreement) resulting from the right of
conversion under the Series B Shares that arises upon the occurrence of a Net
Worth Conversion Event on April 21, 2003, and does not by its terms apply with
respect to any Common Shares acquired by European Re upon exercise of such
rights of conversion. In addition, the Exclusion will no longer



apply (i) following the date which is 10 days after the date on which European
Re provides notice to Trenwick of a Proposed Conversion Date (as defined in the
Rights Agreement) or (ii) if European Re becomes the Beneficial Owner of any
additional Common Shares.

      The description herein of the First Amendment is qualified in its entirety
by reference to the full text of the First Amendment, a copy of which is
attached hereto as Exhibits 99.1 and is incorporated herein by reference.

Item 7. Financial Statements and Exhibits.

(c)   Exhibits

      99.1  Amendment No. 1 to the Rights Agreement, dated as of April 18, 2003,
            by and between Trenwick Group Ltd. and EquiServe Trust Company, N.A.
            (successor to First Chicago Trust Company of New York).


                                       3


                                   SIGNATURES

            Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.

                                            TRENWICK AMERICA CORPORATION


                                            By: /s/ Stephen H. Binet
                                                -------------------------------
                                                Name:   Stephen H. Binet
                                                Title:  President and
                                                        Chief Executive Officer

Dated: April 21, 2003


                                       4


                                  EXHIBIT INDEX

Exhibit No.                            Description
- -----------                            -----------

    99.1          Amendment No. 1 to the Rights Agreement, dated as of April 18,
                  2003, by and between Trenwick Group Ltd. and EquiServe Trust
                  Company, N.A. (successor to First Chicago Trust Company of New
                  York).


                                       5

EX-99.1

                                                                    Exhibit 99.1

                                 AMENDMENT NO. 1
                                     TO THE
                                RIGHTS AGREEMENT
                         DATED AS OF SEPTEMBER 27, 2000
                                 BY AND BETWEEN
                               TRENWICK GROUP LTD.
                                       AND
                     FIRST CHICAGO TRUST COMPANY OF NEW YORK

      This Amendment is made and entered into as of this 18th day of April, 2003
and is hereby made a part of and incorporated into the Rights Agreement dated as
of September 27, 2000 (the "Rights Agreement") by and between Trenwick Group
Ltd., a company organized under the laws of Bermuda (the "Company"), and
EquiServe Trust Company, N.A. (successor to First Chicago Trust Company of New
York) (the "Rights Agent"). Capitalized terms used herein and not otherwise
defined shall have the respective meanings ascribed thereto in the Rights
Agreement.

      WHEREAS, the Company intends that the Board of Directors have flexibility
to determine that a person should be excluded from the definition of Acquiring
Person under the Rights Agreement, provided the determination is made prior to
the time such Person would otherwise become an Acquiring Person;

      NOW THEREFORE, in consideration of the premises and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto hereby agree that:

      1. Definition of Acquiring Person. The definition of Acquiring Person
appearing in Section 1(a) of the Rights Agreement is hereby amended by (A)
deleting the word "or" appearing immediately before clause (vii) thereof; (B)
deleting the period appearing at the end of clause (vii) thereof and inserting a
semicolon and the word "or" in lieu thereof and (C) inserting the following new
clause (viii) immediately after the end of clause (vii) thereof:

            "(viii) any Person who or which the Board determines, prior to the
            time such Person would otherwise be an Acquiring Person, should be
            excluded from the definition of Acquiring Person, provided that the
            Board may make such exclusion subject to such conditions, if any,
            which the Board may determine."

      2. Counterparts. This Amendment may be executed in any number of
counterparts, each of which when so executed and delivered shall constitute an
original instrument, but all such counterparts shall together constitute one and
the same instrument. This Amendment shall become effective and be deemed to have
been executed and delivered by all of the parties at such time as counterparts
shall have been executed and delivered by all of the parties, regardless of
whether each party has executed the same counterpart. It shall not be necessary
when making proof of this



Amendment to account for any counterparts other than a sufficient number of
counterparts which, when taken together, contain signatures of all of the
parties.

      3. Miscellaneous. All other terms and conditions of the Rights Agreement
shall remain unchanged and the Rights Agreement shall remain in full force and
effect.


                                       2


      IN WITNESS WHEREOF, the parties hereto have duly executed this Amendment
as of the date first written above.

                                             TRENWICK GROUP LTD.

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


                                             EQUISERVE TRUST COMPANY, N.A.
                                             (SUCCESSOR TO FIRST CHICAGO
                                             TRUST COMPANY OF NEW YORK)

                                             By:  /s/ Jeffrey Cohen
                                                --------------------------------
                                             Name:  Jeffrey Cohen
                                             Title: Senior Account Manager


                                       3