There has been a myth that UK was required in 1942 by US to exit airliner design, thus putting headwinds on the Brabazon-suite's development. No. Priority in production would be bombers/UK, transports/US, not to inhibit new US bombers, nor Cabinet Committee on Reconstruction Problems from airliners. War Cabinet Minutes W.M.(43).35,25/2/43, SecState for Air, approving Brabazon Committee Types: “We will not accept a solution (to Civil Air Transport) on the basis that we won’t build any a/c and we want authority (to) plan some production”. A US/UK Conference on International Air Transport, 3-7 April,1944 set technical matters which became UN (ICAO) standards; to strengthen UK's stature there, MAP issued ITPs 4/5 April,1944 for Brabazon Interim Type III Empire H.P.88 (Halifax-derived, evolving as Hermes IV) and Avro 687/XX (Lincoln-derived, morphing in Sept.’44 as Avro 688 Tudor I). Commercial issues (to be the Eight Freedoms) were to be addressed in Chicago, Nov.,44. To prepare for that a Ministry of Civil Aviation was formed 8/10/44, to be the sponsor of $ export-earning/import substitution types. Should they have Theseus/Clyde turboprops to dish C-54/C-69 and US' raft of gargantuas like L-89 Constitution? HP and Avro schemed such things, while prototyping their Interims.
What went wrong was this:
1. BOAC finessed "used" L-049, B.377, and part-£ DC-4 (C-4M), and lost any yen for feeble UK Interims;
2. The need for B-29 pressurisation caused (Garrett)AiResearch: all Brabazon Types "leaked" until we sorted this out, structurally, and by Westland licence as Normalair;
3. From late-1946 HP and Avro became distracted from BOAC/BSAAC's Empire business by the prospect of a jet Medium Bomber, won end-1947 by (to be) Victor and Vulcan. Tired Halifax/Lanc retreads took junior priority. Bristol, with zero large structures expertise, was in a field of one for son-of-Type III, Medium Range Empire. BOAC succeeded in dumping Tudor, very nearly ditto on Hermes, and extracted scarce $ for proper equipment, which, they told Ministers, would be self-financing (Bring Over American Currency).