Then as now, and really at every point in between, anyone who was sufficiently grand could secure advancement in the Conservative Party, and it was considered vulgar to enquire as to specific political opinions, then as now, and really at every point in between. Who would look for them in the Conservative Party? Yet the utterly posh world of MI6 and the upper echelons of MI5 was absolutely riddled with them right up until the bitter end, to the point that it had become a standing joke even among the general public. Everyone knew that the KGB’s main recruitment ground was not the patriotic, socially conservative trade union movement or anything like that, but Oxbridge in general and Cambridge in particular, and only the public school rather than the grammar school circles even there.
The perfectly preposterous idea that Harold Wilson, of all people, and for heaven’s sake even Ted Short and George Thomas in the more recent versions, were somehow Soviet sleeper agents continues to serve what has always been its purpose, that of pure distraction from what ought to be the blindingly obvious.