Exhibit 99.10

Date:       June 12, 2002

To:         Eligible Employees of Trenwick Group Ltd.

Subject:    Last Week to Elect to Participate in the Stock Option Exchange
            Program

If you wish to participate in the Stock Option Exchange Program, this Friday is
the deadline for making or changing your election. If you do not make an
election prior to 11:59 p.m. Eastern Time (U.S.) on June 14, 2002, you will not
be allowed to participate in the Stock Option Exchange Program.

Due to the short amount of time remaining, if you want to participate in the
Stock Option Exchange Program or change your election, we strongly recommend
that you send your election form to us via fax (Fax No. 203-353-5550). If you
mail your election or change form this week, there is no guarantee that your
form will be received by June 14th. Remember, your participation or change is
determined by the date we receive your election or change, not the postmark
date.

Election or change forms received after June 14th will NOT be accepted.

If you do NOT want to participate in the Stock Option Exchange Program, you do
not need to make an election. No response from you will mean that your current
options remain in effect under the original terms and conditions of those
options.

If you have any questions, please feel free to call me. My telephone number is
(203) 602-3074.