Bristol LS bus, 1953. Chassis no. 97190, engine no. 92584, registration no. OTT 55, Southern National fleet no. 1701.

The Bristol LS first came into production in 1951 as a result of a joint venture between Bristol Commercial Vehicles and Eastern Coach Works. It was one of the first successful British under-floor engined buses, and one of the first British buses to have unitary construction. For years it was believed the best place for the engine was at the front of the chassis, however with the need to increase seating capacity the design had to be reconsidered. In London the Leyland Tiger with an under floor engine had been produced in 1939, but the Bristol LS was more successful as it solved the low bridge problem with their new design for the chassis and lower deck.