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

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                          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).


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                                   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


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                                  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).


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