The Leave campaign has never looked closer to victory in the EU referendum

Both sides agree that the Brexiters now have unambiguous momentum.

The UK is moving ever closer towards Brexit. On that point, both the Remain and Leave campaigns agree. The polling evidence is now unambiguous. ICM’s latest surveys for the Guardian have Leave ahead by 53-47 in both the online and phone versions (the latter having tended to favour Remain). The vote shares are little changed from a fortnight ago but the hope on the In side was that that poll would prove to be an outlier. It did not. The Leave campaign now has its strongest lead to date in John Curtice’s poll of polls: 52-48 (though as the last general election demonstrated, such numbers are far from infallible).

Remain strategists, whose internal polling also shows the Out side gaining ground, cite two reasons for this shift. The first is the increasing prominence of immigration, Leave’s strongest suit, and the declining focus on the economy. With no means of appeasing those who favour reduced numbers (the EU having rejected limits on free movement), pro-Europeans are left desperately trying to shift the debate back to friendlier territory.

The second is the media dominance of pro-EU Conservative figures, which Remain blames for a slide in Labour support. It was this trend which led No.10 to clear its grid in order to allow free runs for Gordon Brown today and Jeremy Corbyn tomorrow. The hope is that Labour voters, unconvinced or repelled by David Cameron and George Osborne, will be swayed by their own side. Polling two weeks ago showed that nearly half were unaware that their party supported Remain. In today’s ICM poll, 36 per cent of Labour voters back Leave, enough, combined with Tory and Ukip support, to give the Brexiters a clear lead.

Optimists endure among the Remain campaign. They expect most undecided voters to ultimately side with them, rejecting Brexit as the riskier option. Referendums and elections traditionally show a late swing to the status quo. History suggests it would be more surprising were the change side not ahead at this point. Leave’s advantage may heighten the fear regarded as necessary for a Remain win.

But others warn that those toying with Leave may only be emboldened by the polls, welcoming safety in numbers. In the absence of any new offer, the risk for Remain is that it may have no means of winning them back.