It was designed to use the Armstrong Siddeley Mamba ASM.2 which was expected to produce 1,270 shp (950 kW) plus 307 lbf (1,370 N) static thrust for the production aircraft.

Two prototypes - one to be completely fitted out - and a static test fuselage were ordered by the Ministry of Supply and construction started in 1948.

The prototype (serial VX220) first flew from the grass field at Baginton, Coventry on 10 April 1949 for a thirty-minute test flight.

The company started a selling campaign to European airlines but the problems with performance and continual engine difficulties caused the decision in June 1952 to abandon development of the aircraft.

The competing Brabazon IIB design the Vickers Viscount powered by the Rolls-Royce Dart became a best-selling turboprop in the 1950s and 60s.