The Aircraft
In 1944, the Ministry of Supply started the process for contracts for all of these planes. This was carried out in the normal way for government aircraft production. A Ministry Specification was issued and aircraft companies provided designs or prototypes to the specification.
The Type I design developed into Air Ministry Specification 2/44, and was contested by the Bristol Brabazon and the Miles X-15. After a short selection process the Type I was given to the Bristol Aeroplane Company, building on submissions they had made during the war for a "100 ton bomber".
The Type II process was somewhat more complex. Several companies submitted designs to the original specification, but Vickers suggested a move to turboprop power. There was some scepticism on the part of the committee, and in the end they decided to divide the specification in two, allowing the turboprop design to go ahead while at the same time ordering a "backup" piston design as well. This led to a split into the IIA and IIB types, with the de Havilland Dove and Airspeed Ambassador filling the IIA requirement, and the Vickers VC.2 Viceroy and the Armstrong Whitworth AW.55 Apollo filling IIB (specification 8/46).
The Type IIA requirement was developed as the Airspeed Ambassador.
The Type IIB requirement was developed as the Vickers Viscount.
The Type IIIB requirement was developed as the Avro Tudor.
The Type IV went to de Havilland and would become the world's first jet airliner, the Comet.
The Type VA requirement was developed as the Miles Marathon.
The Type VB requirement was developed as the de Havilland Dove.
Read more about this topic: Brabazon Committee