AV8R: (UK) sadly lacked the hard nosed commercial approach that is necessary to succeed in the numbers game of big business.
Until 1987 we owned the Corporation Users and paid some of an aircraft type's Certification cost, repayable by Sales Levy. 1977-1985 we paid all of it as we owned BAe. UK State funding of commercial aircraft began in March,1943 with Bristol T.167. Brabazon Committee's remit was to specify "supreme" types, and in D.H.104 Dove and VC2 Viscount they did. UK funded 100% of civil types' R&D until (Viscount Major) Vanguard, on which we spent £0 (because Vickers wanted to keep all the upside {!}). Then Sandys came along - yes, him. In 1960 he introduced 50% Launch Aid for VC10 for BOAC, Trident for BEAC. Ministers did not choose the types - Corpns. did, bespoke. (BUA chose to be 1-11 and BAC pursuaded Ministers to pony up as Caravelle could not, but they could, sell in US).
The rot that blighted UK civil industry was that while BEAC/BOAC awaited their new types, Ministers got fed up with their losses and required Chairmen to try to spell "efficiency". Floundering in unfamiliar economics, doubtless, as AV8R suggests, aided by US brochuremanship, they forecast VC10/Trident with higher aircraft-mile costs than 707/727, and noisily extracted subsidies to compensate their social service, Jobcentre function on "uncompetitive" British aircraft.
It didn't matter what the outcome was, load factor x yield: Corpns. had their cushion, Boeing/Douglas had ample ammunition to deflect UK salesmen. In fact constant 707 operating enhancements offset VC10's smooth ride. A comparison might be Leyland/Rover models resting on laurels of style while dull Japanese motors would resist corrosion parked on wintry streets, and start at first try. BOAC’s last Super VC10 arrived July,’69; last departure was May,’81. Its last 707 arrived in May,1971; last disposal from BA in June,’83, from (BA-)Br.Airtours in June,1984.