Eighty-five of these highly useful 57′ composite carriages were built between 1914 and 1919. The carriage had three first and five third class compartments with two lavatories, accessible only from two of the first class compartments. They had the non-corridor toplight style of panelling and the elliptical roof profile. These carriages found their way around the entire network, often being used to strengthen express services. With no matching brakes built, sets would have used brakes of an earlier vintage or contemporary stock without lavatory provision. In later years they were used on many cross-country routes and enjoyed long working lives – BR inherited 78 of them, with the last being withdrawn in 1960.