1 EXHIBIT 21 SUBSIDIARIES OF TRENWICK GROUP INC. Name of Subsidiary Jurisdiction of Incorporation - ------------------ ----------------------------- Trenwick America Corporation Delaware Trenwick America Reinsurance Corporation Connecticut (subsidiary of Trenwick America Corporation) Trenwick Holdings Limited United Kingdom Trenwick International Limited United Kingdom (subsidiary of Trenwick Holdings Limited) Trenwick Management Services Limited United Kingdom (subsidiary of Trenwick Holdings Limited) Specialist Risk Underwriters Limited United Kingdom (subsidiary of Trenwick Holdings Limited) Trenwick Services, Ltd. Bermuda Trenwick Guaranty Insurance Company, Ltd. Bermuda (subsidiary of Trenwick Services, Ltd.)