The Great British Overseas Airways Corporation was said to employ lots of "would-be" aircraft designers in its Future Equipment branch - and indeed, BOAC did like to have off-the-peg aircraft crafted to "Saville Row" standards (see their "input" on the Stratocruiser). Vickers did come up with a design which could meet the "non-stop to London from Entebbe" spec, but the stiff (but efficient) fully-slatted wing and the rear-mounted engines added weight - rear-mounted engines mean an "empty" CofG well aft, giving a short tail moment arm, which in turn requires a bigger fin and tailplane area.
Boeing, on the other hand, with its experience from the B-47 and B-52 of flexible wings mass-balanced by the engines, was able to bring in a lower empty weight, and with the Entebbe runway extended (some said paid for surreptitiously by US Government funds), were able to mount a successful counter-attack - seriously helped by the 707's non-recurring costs being largely paid for by the concurrent KC-135 programme.
BOAC's subsequent very public running down of the VC-10 (to justify its decision to go for the 707 after very fully specifying the VC-10) with its miserably weepy "it doesn't do what we want it to do" theme was also a body-blow to Vickers (see also the similar whingeing from BEA about the Trident which they too specified in great detail, with many a change in the process). Add to all this the British government's pressure for the aircraft-building industry to "rationalise" and you can understand why the Vickers bit of what was to become BAC didn't put up much of a fight (or any), naturally preferring to save what could be saved of relations with HMG and the "Overseas Airway".
A very sorry story, for the VC-10 is indeed one of those "looks right" machines - and another of the long series of serious errors by the Powers That Be in the saga of the decline of Britain's aircraft manufacturing industry during the 1960s.
