Interesting to look at the difference PR would mean to the seat allocation in the commons, (FPTP in brackets):
Conservative = 240 (331)
Labour = 198 (232)
UKIP = 82 (1)
Lib Dem = 51 (8)
SNP = 30 (56)
Greens = 25 (1)
That of course is based on the recent vote, I would say it is likely in a PR...