These coaches were built for BR’s Southern Region by the Birmingham Railway Carriage and Wagon Company. They were made up into 25 three car sets numbered 805 to 829 known as ‘Type L’ in line with other three car sets on the Southern. The formation was two of these coaches with a corridor composite to D2320 (Comet Models S17K) between them, with the first class end next to the even numbered brake coach. They entered service between August 1948 and May 1949 on the South Western section. For summer traffic, some sets were strengthened with a pair of corridor thirds (Comet Models S2AK). Maunsell coaches may have been used but there is strong evidence that they were usually Bulleids.