Lord Ashcroft has published his latest survey of marginal seats, this time concentrating on Tory-Labour battlegrounds.

A lot of media attention has focused on the fact Ukip topped the poll in two seats: Thurrock and Thanet South. But taking a broader view, Ashcroft’s findings suggest this is a battleground that is still very much Labour’s to lose. In some seats Labour’s poll lead has gone up; in others it has gone down. But overall there is a swing away from the Tories that would be big enough to deliver Labour a small but manageable parliamentary majority.

Here are five thoughts on the poll results:

1. Ashcroft’s fieldwork suggests every one of the 10 Tory seats most vulnerable to Labour would change hands were the election held tomorrow. Labour would gain only nine of them, however. Lord Ashcroft’s poll in Thurrock put Ukip in first place on 36%, Labour second on 30% and the Tories third on 28%. Here’s a reminder of those top 10 seats:

He also commissioned polls in four other Tory-Labour marginals: Waveney, Morecambe & Lunesdale (both showing a Labour gain), Great Yarmouth (a Tory hold) and Thanet South (a Ukip gain).

2. The seats in which Labour’s poll lead has increased are all predominantly urban or metropolitan areas. Hendon, Cardiff North, Warwickshire North and Wolverhampton South West are the only constituencies featured in Ashcroft’s survey where the gap in percentage points between Labour and the Conservatives has gone up when compared with similar polls earlier in the year.

I suspect this could well prove to be one of the key patterns in the 2015 election, with Labour doing much better in marginals based in or around towns and cities than those in more rural locations.

3. The Liberal Democrats scored an average of just 4% over the seats polled. This is an 11-point drop since 2010, and were it repeated on polling day would see them lose their deposits in 10 of the 14 seats. The sight of Lib Dems losing deposits could well be one of the recurring motifs of election night.

4. The swing from Tory to Labour is currently very inconsistent. Ashcroft’s polls found a very modest 2% swing in Stockton South and a thumping 9% swing in Wolverhampton South West. This chimes in with the equally irregular swings evident in Ashcroft’s other recent polls of marginal seats.

5. I remain unconvinced that Ukip will win any seats in 2015. Even though these new polls put them in front in both Thurrock and Thanet South, when it comes to the real poll I think a number of factors will come into play – not least the kind of anti-Ukip tactical voting that was in evidence during the Newark by-election.

There’ll also be some unravelling of Ukip support as polling day nears and people instinctively revert to more traditional party loyalties. We’ll see the kind of intense media scrutiny of Ukip that crescendoed just before May’s local elections, and which may expose a rotten apple or two. Plus Lord Ashcroft carried out most of his polling in June, when Ukip’s support was still on a post-EU election bounce – a bounce that now seems to be over.

As a sidenote, Ashcroft’s polls suggest that once again Ukip performs very poorly in urban areas. They scored just 9% in Hendon, 12% in Cardiff North and 15% in Wolverhampton South West.