Re:Sandys
Well, considering Surface to Air Missiles, such as the Bloodhound 3 missile, (based on the cancelled 100 mile range missile codenamed Blue Envoy), intended to carry a 10Kt nuclear warhead, codenamed Indigo Hammer, were potentially about to enter service in the early 1960's, you can understand why Duncan Sandys was dismissive of manned fighter aircraft...
The reason why Bloodhound 3 never entered service, with Indigo Hammer onboard, was that British nuclear reactors could not produce enough weapons grade fissile material at the time, to make it...
As for TSR-2 & P1154 failing to enter service, you could argue that was the fault of the Royal Navy (Who wanted their precious Queen Elizabeth class "Super Carriers" built), & Rolls Royce (Reason - Both Projects were powered by their rival's (Bristol Siddley) engines, namely the Olympus, in the case of TSR-2, & BS.100, a larger version of Pegasus, intended to use reheat/afterburning to achieve Mach 1.5 at altitude).