DUP chief whip Jeffrey Donaldson made an intriguing contribution to last night’s Newsnight, broadcast live from Belfast.

As was to be expected, Donaldson insisted that he and his colleagues would use their influence in a hung parliament to prevent the passage of Boris Johnson’s Brexit deal, to which the DUP are so vociferously opposed.

So far, so familiar. But then came a subtle but significant shift. Asked repeatedly whether the DUP could ever support a second referendum or a minority government that proposed one, Donaldson said only that it was not an idea to be considered “at this stage”. Pressed further, he said he would rule it in nor out.

While far from a full-throated endorsement, his choice of words was significant. Even though its argument that anything is better for the union than Johnson’s Brexit deal dictates that it can and arguably should become a Remain party, the DUP has hitherto insisted that it wishes to see the result of the 2016 referendum respected no matter what — provided, of course, Northern Ireland leaves on the same terms.

With every Conservative candidate signed up to a pledge to support the withdrawal in the next parliament, that is very unlikely to happen. In that respect, Donaldson’s decision to publicly edge towards a second referendum — and verbalise the logic that has been implicit in the DUP’s position all along — is a belated recognition of reality.

We might ask why he has chosen to do this now. In the seats where the DUP is under threat — most notably in marginal North Belfast, where Nigel Dodds is facing a concerted challenge from Sinn Féin — their opponents want to make the race about Brexit. The swing electorate in that constituency is made up of nationalists and Remainers who would not ordinarily vote for the republicans, be it for reasons of history or out of disagreement with abstentionism. If its core vote is not enough to ensure safety, then the DUP must convince at least some of those who would have otherwise voted SDLP or Green that a vote for Dodds does not necessarily mean a vote for Brexit.

Can it work? One might ask whether it is too little, too late. But it is nonetheless a telling indication of where one of the DUP’s more conciliatory thinkers believes his party is most vulnerable. It also offers a clue as to the strategic direction DUP MPs might take without Dodds in a hung parliament.

And there are questions for Labour too. Donaldson made sure to append a caveat to his argument which was that the DUP would not do business with Jeremy Corbyn. He added, however, that the Labour leader might soon be replaced. In a week where crossbench peer and Labour adviser Bob Kerslake has caused much disquiet in Corbynite circles with the suggestion that a change of leadership might have to be up for negotiation in a hung parliament, it is an uncomfortable reminder that Corbyn’s likeliest route to a majority might run through his resignation.