RB - correct me if I'm wrong, but isn't AV just a ranked preference version of FPTP? To my admittedly untutored eyes, it seems like this would strengthen a FPTP system by further eliminating the effects of third party spoilers (as LD has done in the past and UKIP is likely to do now). PR results in everyone getting a piece of the pie - AV results in only mainstream candidates getting into Parliament, and largely eliminates tactical voting to boot.

I personally think PR is a mess - yes, it might be more inclusive, and as such has a place in countries riven by stark ethnic, cultural, or religious divides (and now, I'm not talking about Scotland and Wales - more like Kurds, Sunnis, and Shiites). But it often results in less stable governing coalitions and reversions to identity politics for ever-smaller groupings. There are fixes to the problems of PR, but I think people rate it too highly for 'fairness' over more majoritarian systems.

That being said, FPTP fails when the two main parties fail to provide compelling narratives simultaneous with the growth of nativist regional parties with no national significance. The UK's parliamentary system is fundamentally adversarial and confrontational, which is not conducive to the sort of coalition building and compromises necessary in a majority-free world. Much as it is deeply flawed, the US Congress benefits from the fact that government is formed and can (theoretically) function even in the absence of a legislative majority for the party of the executive - this has led to a long history of (grudging) compromise between the parties. In the UK, the government goes about its business with barely a by-your-leave from the opposition, which doesn't lead to much in the way of dealmaking or coalition building. It seems like AV would reinforce a FPTP system rather than weaken it.

I get your comments about there already being a (rejected, poor participation) referendum on the topic. And maybe the UK isn't interested in it. That's fine. But I see the logic of AV as a way to strengthen, rather than weaken, a FPTP-based two party system.

In terms of the election, I don't see much in the way of hope for the Tories unless there's a late surge in a number of marginal constituencies. Labor is likely to form the next government, but it will be cobbled together and quite weak.