The 1800 Roadster, model number 18TR, was designed in the closing days of World War II. Triumph had been bought by the Standard Motor Company in 1944, and the managing director of Standard, Sir John Black, wanted a sports car to take on Jaguar, which had used Standard engines in the pre-war period. Frank Callaby was selected to style the new car. After getting Black's approval for the general shape, Callaby worked with Arthur Ballard to design the details of the body. Design of the rolling chassis was by Ray Turner. Walter Belgrove, who had styled the pre-war Triumphs and was employed as Chief Body Engineer, had no part in the design.