OP gave date as after Summer 1940 so Norway and France are goneI don't think history is anything like that fixed. If under a popular and politically effective Tory leader the Falls of France and Norway had been avoided via a blunted sickle with Germany being starved out and Nazi's falling to a military coup in 1941 it's hard to imagine anything other than a substantial Tory victory in the ensuing election, appeasement could be sold as a successful policy that bought time and the electorate would reward them. On a spectrum between a best case scenario and the worst possible Allied victory scenario for the Tories I think OTL is pretty far towards the worst possible scenario.