GAM-87 Skybolt was not beloved by RAF or USAF and SAC
the Air-launch ballistic missile could be launch by modified civilian aircraft, like a Vickers VC-10 (study by Ministry of defense)
while in time SAC lobby for a Mach 3 Bomber like XB-70, not for a subsonic C-130 pact full with Skybolt's
In same time the USAF start deployment of Minuteman & Titan II ICBM and US Navy there Polaris SLBM, making the Skybolt "obsolete".
finally it was US secretary of Defense Robert McNamara, misbelieve that ICBM and SLBM could replace Strategic bombers.
So he canceled the Skybolt program, forgetting that the British had put all there effort in the ALBM system and canceled allot of programs for it.
What let into a major crisis between the British and USA, an emergency meeting between parties from the US and UK was called, leading to the Nassau agreement.
in the end it the USA formal apology to British and gave them access to Polaris SLBM hardware.
but what if, the British government, had insisted that USA stay on agreement and delivery the Skybold ?
there some hint that Robert McNamara was willing to reactivate the Skybolt program for British use only.