Chuka Ummuna calls for "proper proportional representation" on Ridge on Sunday. #Ridge

That will appeal to a lot of people!

It's possible to imagine that TIG might pick up most of the votes that would normally go to the Greens, Libdems, even UKIP, etc. for one GE anyway, because of the possibility of getting the grand prize of PR out of it. Remember, PR benefits every party bar the Tories and Labour.

You should also bear in mind that votes under PR might distribute themselves very differently than now, because there's no longer any need to "hold your nose" and vote for a party you're not fully in tune with, just because the one you agree with has no chance of winning.