The Staggers 26 November 2014 ComRes suggest Labour’s summer leads in the key marginals are intact We can compare tonight’s poll with Ashcroft’s seat-by-seat polls of Tory-Labour marginals. The Labour lead in tonight's poll of 40 Tory-Labour marginals was 8 per cent; Ashcroft has showed an average 9.8 per cent lead in 37 of these seats. Photo: Getty. Sign UpGet the New Statesman's Morning Call email. Sign-up For daily news, analysis and polling, explore May2015.com. Tonight’s poll from ComRes for ITV is more interesting than most. It gives us an insight into one of, if not the, key election questions: what will the swing be between the Tories and Labour in May? More specifically, how many Tory-held seats will Labour win? The news is encouraging for Labour – far more than the potentially temporary national poll spike three pollsters handed them on Monday. ComRes have grouped voters across the 40 most marginal Tory-Lab seats: 25 are those the Tories won by the narrowest majorities in 2010 (the most “marginal” seats), and 15 are the closest marginals won by Labour. It has then worked out the popularity of the parties across those 40 seats. This doesn’t give us any insight into how the parties are doing in these individual seats, as Ashcroft’s seat-by-seat polls do, but we can compare ComRes’ vote shares with the collective vote shares given by Ashcroft’s polls. This gives us an idea of whether the critical poll leads Ashcroft handed Labour earlier in the summer are still in tact. The data, in so far as it goes, suggests they are. Ashcroft has polled those 25 Tory-held seats (and 18 others), as well as 12 of the 15 Labour seats ComRes polled. The average lead he handed Labour in those 37 seats was 9.8 points. ComRes tonight gave Labour a very similar 8 point lead across those 37 (and three more Labour-held seats Ashcroft hasn’t polled, because they will likely show strong Labour leads). This is interesting because Labour have fallen slightly in the national polls since many of these Ashcroft polls. His 12 polls of Labour-held polls came out in May, his first 12 Tory-held seat polls were released in July, the next 8 came out in August, and 12 more (5 of which we are interested in for this comparison) were published in October. This is how Labour has fared in the national polls since late July. If that slight national dip hasn’t affected Labour in the marginals that matter, the party could still be on course to win many of the seats Ashcroft’s polls have handed them leads in. Explore May2015.com. › The quest for completion: on Bob Dylan and the Basement Tapes Harry Lambert is special correspondent at the New Statesman. He tweets at @harrytlambert. Subscribe For daily analysis & more political coverage from Westminster and beyond subscribe for just £1 per month!