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                                                                    EXHIBIT 32.1

                           PRINCIPAL EXECUTIVE OFFICER
                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350,
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Annual Report of White Mountains Insurance Group, Ltd.
(the "Company") on Form 10-K for the period ending December 31, 2004 as filed
with the Securities and Exchange Commission on the date hereof (the "Report"),
I, Raymond Barrette, President and Chief Executive Officer of the Company,
certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906
of the Sarbanes-Oxley Act of 2002, that to my knowledge:

(a)  The Report fully complies with the requirements of Section 13(a) or 15(d)
     of the Securities Exchange Act of 1934; and,

(b)  The information contained in the Report fairly presents, in all material
     respects, the financial condition and results of operations of the Company
     as of and for the periods presented in the Report.


/s/ Raymond Barrette
President and Chief Executive Officer
(Principal Executive Officer)

March 1, 2005