There’s an interesting article on the BBC analysing what would have happened if AV had been introduced in 1983.
The assumption is that people wouldn’t have made any change to their first preference (and I think this is quite doubtful), but it’s still very interesting:
The conclusion is there wouldn’t have been any change to the winning party, but interestingly, the Conservatives would have been completely wiped out and replaced by the LibDems back in 1997.
I would prefer a proper proportional system (such as d’Hondt), but I do think AV is better than FPTP, mainly because it doesn’t require the voter to decide on their preferred candidate’s electability prior to casting their vote.
That said, I do expect the Tories to win the election, and they will unfortunately never allow the AV referendum to go ahead.