In light of Corbynmania, I've been set thinking about one of the last times a lefty candidate stood (the only one in the meantime who passed the nomination threshold was Abbott in 2010, of course). This was Bryan Gould, a New Zealand immigrant who had risen to medium office in Kinnock's Shadow Cabinet. In the end, he only won 9% of the vote against the juggernaut that was John Smith.
But what if Gould had run a better campaign, and Smith had died two years early? Presumably, people like Meacher, Kaufman and Cook would still keep their hats out of the ring, and probably support Gould. The modernisers discussed a Brown candidacy IOTL, so it looks like a straight fight between Gould and Brown, which looks a lot more winnable for Gould.
So what happens in the event of a Gould victory? Does the UK still sign the Maastricht Treaty with the LotO a Eurosceptic? And if the Maastricht vote loses Major the confidence of the house, does Gould win the ensuing election? On the other hand, if Major struggles on to 1997 (with Gould presumably winning) what sort of stuff does the Gould Ministry do?