Here's a concern though: the inflow from erstwhile Lib Dem/Green voters after the last election does not match the outflow to UKIP or non-voters that is ongoing. As Carswell pointed out nicely, you can join a party for twenty five quid online these days, and in and of itself political party membership means little (how many are actually involved?). And this is just from casually browsing through YouGov data and voting records for a chunk of constituencies. You've also got to account for the 'must join a cause' factor after electoral drubbings. It's reasonably common but doesn't last.
Of secondary worry for Corbyn is the demographic profile. If it remains reasonably middle-class, educated and predominantly metropolitan -- he won't go anywhere electorally. Namely there aren't enough of them to make much of a difference, even if we assume 2/3 turnout can be maintained.
If Corbyn hangs on and the party stays together, I wouldn't be surprised to eventually see the Tories as the largest party with a waning base and everyone else grabbing an increasingly even proportion of the vote. Under FPTP, and even PR, such a distribution would be laughable as a force for change or ideological purity (imagine the rainbow coalitions that would be required!).
Anyway. A resolution is needed soon. Indeed for the sake of all the mooted economic reforms, a Corbynite would be wiser holding on to the shadow chancellor seat rather than No 10 in waiting. But that's my crackpot idea of a joint ticket/informal Labour coalition to get PR (a sort of Blair/Brown, only this time Blair/Corbynite?). I doubt the party will ever be as sensible as that to take back power. It's sad to see that they are probably more keen on the legal ambiguities of their rulebook, atm. What a mess.
