Survation has published the results of a poll it carried out on behalf of the RMT union in four “commuter” constituencies on the outskirts of London.

None of the four are ultra-marginals, but they are all Tory-Labour battlegrounds and all seats Labour would need to win if it wants a comfortable majority in the next parliament.

I’m a bit surprised by what the poll suggests. I personally think all four of these seats are out of Labour’s reach, but Survation’s data implies at least two might be up for grabs.

The first seat, Stevenage, would need a 4% swing from Tory to Labour to change hands. Current MP Stephen McPartland has a majority of 3,578. Labour increased its hold on Stevenage council in last month’s local elections. It now has a very safe majority of 29 seats, while the Tories have only two councillors in total.

Milton Keynes South would fall to Labour on a 4.7% swing. Iain Stewart has a majority here of 5,201. Labour has just replaced the Tories as the largest party on Milton Keynes council, but fell four short of getting an outright majority.

With the other two seats, we’re edging into the realms of a Labour landslide. Henry Smith’s majority in Crawley is 5,928, while Alok Sharma’s majority in Reading West is 6,004. Though neither could be described as safe Conservatives seats, and both were held by Labour until 2010, for the Tories to lose places like these next year would mean they were having a bad election. Crawley is 93rd on Labour’s target list, while Reading West is 95th.

Survation rightly points out that although its poll gives Labour an average lead of four points across the quartet of seats, this does not mean the party would win all of them on a uniform swing.

Labour’s share in the poll is not distributed evenly across the four. Survation’s data tables suggest the Tories are actually ahead in Milton Keynes South, neck and neck with Labour in Crawley, and behind in Reading West and Stevenage.

The usual caveat applies: this is a snapshot, not a prediction. But if nothing else the poll is a reminder that seats lying outside projected swings and mathematical forecasts could still change hands.

Saying that, Labour’s concern ought to be not whether it can win its 95th target seat, but whether it can do the same in the previous 94.