Introduced at the October 1923 Olympia Motor Show, the Sunbeam 20/60 was a direct rival to the Rolls-Royce 20hp and in some ways its superior.

Just as technologically advanced, the Wolverhampton machine’s 3181cc engine boasted a seven-bearing crankshaft, overhead valves and a detachable cylinder head but was rather more powerful than its Derby counterpart’s 3127cc unit.

Employing an extra forward ratio in its gearbox and drum brakes to both axles (as opposed to the rear one only), the Sunbeam was not only faster – speeds of up to 70mph were possible dependent upon the coachwork fitted – but also offered better retardation.

Well judged leaf-sprung suspension (semi-elliptic front / cantilever rear) gave a supple ride, while catalogued bodystyles encompassed a Tourer, Sports Model, Enclosed Limousine and Enclosed Landaulette.

A singularly accomplished design, the 20/60 is known to have caused Henry Royce consternation especially as the 1920s was the decade which arguably saw Sunbeam a...