THIRD AMENDMENT TO LETTER OF CREDIT FACILITY AND REIMBURSEMENT AGREEMENT

Exhibit 10.19

THIRD AMENDMENT TO LETTER OF CREDIT FACILITY

AND REIMBURSEMENT AGREEMENT

            THIS THIRD AMENDMENT TO LETTER OF CREDIT FACILITY AND REIMBURSEMENT AGREEMENT, dated as of December 23, 2003 (this “Third Amendment”), by and among XL Insurance (Bermuda) Ltd (formerly XL Insurance Ltd), XL Capital Ltd, XL Europe Ltd, XL Re Ltd (formerly XL Mid Ocean Reinsurance Ltd), XL London Market Group plc (formerly The Brockbank Group plc) and XL Investments Ltd (each a “XL Party” and collectively, the “XL Parties”) and Mellon Bank, N.A., as Issuing Bank (in such capacity, the “Issuing Bank”) and as Agent (in such capacity, the “Agent”) and as a Bank (in such capacity, the “Bank”)

W I T N E S S E T H:

            WHEREAS, the XL Parties, the Bank, the Issuing Bank and the Agent are parties to a Letter of Credit Facility and Reimbursement Agreement, dated as of June 30, 1999, as amended by the First Amendment to Letter of Credit Facility and Reimbursement Agreement, dated as of February 25, 2000 and the Second Amendment to Letter of Credit Facility and Reimbursement Agreement, dated as of November 28, 2000 (the “Reimbursement Agreement”), pursuant to which the Bank has agreed, on the terms and subject to the conditions described therein, to extend credit to certain of the XL Parties by participating in letters of credit issued for the account of such XL Party by the Issuing Bank;

            WHEREAS, the XL Parties have requested the Bank to make certain additional changes to the Reimbursement Agreement;

            WHEREAS, the Bank is willing to amend the Reimbursement Agreement as set forth below; and

            WHEREAS, capitalized terms used herein and not otherwise defined shall have the meanings assigned to them in the Reimbursement Agreement;

            NOW THEREFORE, in consideration of the premises and of the mutual covenants herein contained, and intending to be legally bound hereby, the parties hereto agree as follows:

SECTION 1. AMENDMENTS TO REIMBURSEMENT AGREEMENT.

            (a)   Section 1.01 of the Reimbursement Agreement is hereby amended by adding thereto, in proper alphabetical sequence, the following definition:

                “XL Parties” shall mean the Credit Parties and “XL Party” shall mean Credit Party.