Brabazon Type III was revised several times, all the committee Types were but this one more so than the others. The original recommendation said:
Landplane for Empire trunk routes (York replacement)
Four engines; operational cruising speed not less than 225mph at 10,000ft, greatest payload (passengers, mail and freight) feasible with current engine types, still air range 3,500 statute miles.
Such a Type was the focus of BOAC's plans for post war years, equivalent to their notional Group 'A' and 'B' requirements.
One of the first projects to address the requirement in late 1943 was the Avro XXI, the origin of the Tudor II, and later, 1946-47, after the requirements had been thoroughly revised, Bristol submitted their Type 175, the start of the Britannia.