Hawker Siddeley HS 748 Paper ended most military manned-aircraft development in the UK, and Avro decided to re-enter the civilian market. The Vickers Viscount had the larger end of the short-haul market, and Avro therefore decided to design a smaller regional airliner powered by two Rolls-Royce Dart turboprop engines, intended to replace the many DC-3 Dakotas that were by then reaching the end of their economic lifespan. Original plans were for a 20–30 seat aircraft with a similar configuration to the Fokker F27, but talks with potential customers soon led to a low-wing 40-seat design being chosen for the 748 project. Avro was not
Vickers Valiant military aircraft. It was followed by the Vanguard, a passenger turboprop designed in 1959, and the Vickers VC10, a jet passenger aircraft in 1962, also used as a military transport and tanker by the RAF. The Valiant was a conservative design of the era, having a shoulder-mounted wing and four Rolls-Royce Avon RA.3 turbojet engines, each providing up to of thrust, installed in pairs in fireproof bays in each wing root. The design of the Valiant gave an overall impression of a plain and clean aircraft with simple aerodynamics. George Edwards described the Valiant appropriately and simply as an "unfunny"