The service originated in 1891 when the FR Co. was party to an agreement on the carriage of Railway Letters made between the G.P.O. and most of the British Railway Companies (operating through the Railway Clearing House).
The agreement, permitting the carriage of letters more quickly than by the normal postal service, became effective nationally on 1 February 1891[REF] and the FR Co. signed the agreement on 28 May 1891.