Re: Old Tech
One could validly make the argument that it was the Royal Navy that effectively "scuttled" both TSR 2 and P.1154, as they wanted to ensure the money that would not be spent on said programmes, would go to support their "Pet Project", the Queen Elizabeth class "supercarrier" programme a/k/a CVA-01/02.
(Reportedly, said "Supercarrier's" would have weighed some 60,000 tons, & been larger than the USS Enterprise, their nearest U.S equivalent. ).
To that extent, they actively sabotaged the P.1154 programme, by insisting on a naval version for the Fleet Air Arm, which was effectively a completely different aircraft, to the single seat strike version the RAF wanted, in that it had a far larger wing span to the RAF version, had a 2 man crew, & was optimised for long range interception.
The radar/fire control system for this version, would at best reach a beta test version in 1970, & probably would have taken until 1975 to reach full operational service...
Because of the Royal Navy's activities, the unit cost for P.1154 reached a unacceptable level & the P.1154 programme was cancelled.
Ironically, CVA-01 was itself cancelled, due in part to the worsening dispartity between the Pound & Dollar, which reached crisis level in 1967, caused by the failure of the previous McMillian government to decouple the Pound from the Gold Standard, at the same time the U.S decoupled the Dollar from the same standard, in the early 1960's...
The Final twist in this tale, is that BAC & McDonnell Douglas offered a supersonic version of the Harrier, using a PCB enhanced Pegasus (now owned by Rolls Royce), capable of Mach 1.2, but using existing Harrier/AV-8A airframes (with slight modifications) to the U.S Marine Corps & the RAF under the name AV-16X, in the early 1970's.
However both parties refused to go along with this proposal for various reasons...