We’ve cut the odds on the Greens out-polling the Lib Dems in 2015 from 5/1 to 4/1 today. That follows last night YouGov poll which put the Greens ahead.

Pretty staggering considering that at the last general election the Liberal Democrats got twenty five times as many votes as the Greens. There’s a good Telegraph article here which highlights some of the main issues behind the Green rise in the polls.

I think there are a couple of factors which would make me slightly wary about taking the 4/1 though.

1. How many candidates will they stand? In 2010, the Greens stood in just 310 UK constituencies i.e. under half. This time they are reported to be aiming for three quarters, which would be something around 490. No matter how bad things get for the Lib Dems, I’m sure they will still be on the ballot in the 631 seats outside of Northern Ireland (and the Speaker’s seat).So the Greens would have to get 28% more votes per seat contested than the Lib Dems to outscore them nationwide. That might not be as difficult as it sounds; presumably the seats they won’t contest will be the less favourable ones for them anyway.

2. Will they fade away in the campaign? If the current TV debate proposals go ahead, then Nick Clegg will be in two of the three debates. The Greens won’t feature in any. The Green’s most skilled media performer, Caroline Lucas, will be busy trying to hang on to their one seat in Brighton Pavilion (she’s currently a marginal favourite), so the face of their campaign will be leader Natalie Bennett, who hasn’t convinced everybody yet.

Until recently, most of us had been assuming that the Greens would have enough of a job holding on to their one seat in Brighton Pavilion. Perhaps an outside chance in Norwich South, but that was about it. Some good recent national opinion polls have led to speculation that they might do a bit better than that.

Let’s have a look at their chances in the 12 target seats mentioned in The Guardian, as indicated by the current constituency odds at Ladbrokes:

SeatWin 2010%Maj 2010Green Odds
Brighton PavilionGreen2.410/11
Norwich SouthLib-Dem0.76/1
Bristol WestLib-Dem20.510/1
St IvesLib-Dem3.725/1
Sheffield CentralLabour0.425/1
Holborn & St PancrasLabour18.225/1
Liverpool RiversideLabour36.525/1
SolihullLib-Dem0.333/1
York CentralLabour13.933/1
Oxford EastLabour8.933/1
Reading EastConservative15.233/1
CambridgeLib-Dem13.650/1

Bristol West came as a bit of a surprise to me when people started backing it at 100/1. Now 10/1, that would be a very expensive result for Ladbrokes. Perhaps not quite as bad as Brighton Pavilion in 2010, which was one of the biggest betting contests out of all 650 UK constituencies. Caroline Lucas only just scraped home back then, but the Greens had been backed in from 5/1.

Norwich South was their number two target at the last election, and there’s not reason why they couldn’t go close again in 2015. If, as expected, the Liberal Democrats are turfed out with a vastly reduced vote, the seat is very much up for grabs between Labour and the Greens. I’m starting to think 6/1 might be a big price there.

It looks like their other hopes are mostly seats with big student/university populations and classic Guardianista territory. It looks a big ask for them to actually win any of these, so we’re quoting 25/1 that the party wins six or more seats next May.