The Tories would have cancelled it had the General Election gone the other way, this was no Socialist conspiracy. P1154 simply did not work and we still can't do VSTOL Plenum Chamber Nozzle after-burning now. RR tried it again in the 80's and still couldn't manage it.
Oh, and as for TSR-2/F-111K/MRCA and Moscow, that is a real distraction. The range requirement for TSR-2 came from the Far east and not Europe. When we pulled out of the Far east the range commitment went too.