After getting Black's approval for the general shape, Callaby worked with Arthur Ballard to design the details of the body.

Walter Belgrove, who had styled the pre-war Triumphs and was employed as Chief Body Engineer, had no part in the design.

[9] The Triumph version featured a downdraught Solex carburettor instead of the Jaguar's side-draught SU, and a 6.7:1 compression ratio instead of 7.6:1.

[10] The tubular steel chassis was a short-wheelbase version of the 1800 saloon, featuring transverse leaf sprung independent suspension at the front and a live axle with semi-elliptic springs at the rear.

The car's unusual width also made it necessary to fit three screen wipers in a row, an example followed by early shallow windscreen Jaguar E Types.

[3] The only significant upgrade in the Roadster's production came in September 1948 for the 1949 models, when the 2088 cc Vanguard engine, transmission, and rear axle were fitted.

[2] This car was announced and a sample displayed at the October 1950 motor shows in Paris and at Earls Court on stand 145.

Its full-width body was built on a Standard Vanguard chassis with an engine given twin down-draught carburettors and a higher output.

[14] The British actor John Nettles drove a red 1947 Triumph Roadster 1800 in the 1980s BBC television crime series Bergerac, set on the Channel Island of Jersey.