The records were deposited by the company in 1974, through the Insurance Records Survey and placed on permanent loan with the agreement of the Manager and Underwriter. Although some records date from the 1930s, most relate primarily to the 1950s and 1960s. They are arranged in their natural order in the insurance process, followed by company records and correspondence. They include: Head Office Books, 1957 to 1968, containing registers of debits against policies, with some details of ships, cargoes and voyages; hull closings, 1957 to 1964; cargo closings, 1957 to 1964; building and port risks, 1937 to 1960; book and proof sheets, 1957 to 1968, summarizing business and premiums paid; declarations and certificates, 1957 to 1970, containing details of cargoes sent; premiums and policies, 1932 to 1970; treaties relating to reinsurance, 1957 to 1967; reinsurance agreements, 1950 to 1969; reinsurance closures and recoveries, 1958 to 1969; records of client companies, 1945 to 1966; claims records, 1933 to 1969; salvage records, 1952 to 1966. The company records include: correspondence, 1945 to 1966; ledgers and cash books, 1917 to 1969; investment records, 1911 to 1948; and results and accounts, 1923 to 1967.

Administrative / biographical background
The Marine Insurance Company is an insurance company dealing in marine, aviation and transit insurance, based in Leadenhall Street, London. It was established in 1836 and became a limited liability company in 1881. In 1917 it became part of the London and Lancashire Insurance Group and since 1961 it has been a member of the Royal Group of insurance companies.