What is unlikely is that he would ever have moved from a generally Left-wing perspective towards any tolerance whatever for the Right in general or the Conservative Party in particular. He did not have it in him.
He was highly critical of the Labour party, but from within democratic socialism - if he laid information with the authorities about various Labour MPs, it is because he genuinely thought that they might be Soviet agents. We have the luxury of knowing that Tom Driberg - who did not, I think, make his list - was talking to the KGB regularly, but was also talking to MI5.
In the last few days, friends like auntysarah have voiced what I believe to be a fundamental misunderstanding of Orwell's 1984. To paraphrase, Orwell prophetically got the number of New Labour and saw the Labour Party as the precursor of the Ingsoc of Big Brother.
Now, obviously, in his portrayal of a future British totalitarianism, Orwell drew on much that was authentically British - it needed to feel real. He drew on the Civil service, municipal jobsworths and nasty cheap cafes; he also drew on two things he knew very well, the BBC and the Labour Party, but the BBC far more. To say this is not to say that he thought the BBC would evolve into a totalitarian regime - he thought that a totalitarian British regime would need to reflect the workings of the BBC because that is what big British organizations are like. A regime that claimed to be socialist would obviously draw on the traditions of the Labour party - which is not the same as saying that he was foreshadowing Blairism and seeing it as totalitarian.
What really worried him - and what 1984 is at least as much about as socialism - is managerialism; he wrote several times, and rather rudely, about James Burnham and the sort of industrial feudalism that is creeping back into our lives.
So, no, Orwell would have hated Blairism and Brownism, but he would not have endorsed David Cameron or Nick Clegg - and his scorn would have been in good prose...