Having looked at the Conservative side of the picture, it's time to look at things from a Labour perspective. So here are the important seats for Labour, arranged by odds:
I've included Labour's top 125 targets, the 35 most marginal Labour held seats and any other seat where the odds on Labour are between 1/10 and 10/1.
You will see that some seats that Labour already hold are seen as rather less safe bets than some seats that they are targeting. I struggle to see why Southampton Itchen should have a better price on Labour than Waveney or Birmingham Edgbaston should have a better price on Labour than North Warwickshire. Sentiment on individual constituencies can lead to skewings of prices in aggregate.
How are Labour shaping up? To gain an overall majority, they need to take 68 seats. If these seats fall in the order of the current odds, the 68th extra seat is Portsmouth North, for which Labour are quoted 5/4. You can back an overall majority for Labour at 9/4 with Betfair as I write, and odds of 2/1 are widely available with conventional bookies on the same proposition.
It's a similar story when you look at proxies for a bet on Labour most seats. If these seats fall in the order of the current odds, Labour would have 290 seats if it took Nuneaton (odds 4/9) and 300 seats if it took City of Chester (odds 4/7). You can back Labour most seats at 10/11 with Bet365 or Betfair as I write.
That means that you generally will get much better value by betting on the general markets than on the constituency markets if you want to back Labour (and the 10/11 on Labour getting most seats in particular looks like good value). You should only be wanting to back Labour in an individual constituency if you are confident that the price is wildly out of line or if you have compelling local knowledge.
The conventional Conservative/Labour marginals don't offer much value on the Labour side, in my opinion. The few seats where Labour may be worth backing in individual constituencies rather than the general markets are those where Labour faces different opponents. and in particular the Lib Dems. In Scotland, the Lib Dems' polling remains appalling. Labour should be considerably shorter than 4/5 in Edinburgh West. Simon Hughes may be hugely personally popular in his constituency, but the Lib Dems are being flattened in London at present, and 2/1 on Labour taking his seat also looks like good value.
I looked at the Labour targets in April:
Since then, there has been a slight drifting of Labour prices in their targets, mirroring the slight tightening on the Conservative side in their own seats.
Finally we can look at the Labour battleground and the Conservative battleground together, to see how the two battlegrounds dovetail. The link to the Conservative battleground is here:
The hinge point is at Nuneaton at present: appropriate for a place very close to the centre of the country. If all seats fell in order of odds on both sides to that point, the Lib Dems would lose 22 seats to Labour and the Conservatives. Right now, I expect the Lib Dems would take that. Who has most seats may well depend on which of the main parties can take most of their Lib Dem targets.