Labour missed a trick by not backing this. Even if Labour win a landslide this time, in the long run, the current broken system favours the Tories more than anyone. IMO everyone on the left should back electoral reform both for reasons of fairness and because it aligns tactically with their interests. The fact that a fairer system aligns with the interests of the left rather than the right isn't a coincidence.
That may be horribly reformist of me, but PR would open up various possibilities for realignment, as we have seen in Spain, which has various political similarities to the UK.