Theresa May’s Brexit deal dead as DUP says it will not back agreement ‘under any circumstances’

'We would damage irrevocably our trading relationship with our biggest market, which is the rest of the UK, and we are sitting in a waiting room for constitutional change. And we simply can’t accept that'

The Democratic Unionist Party has hammered the final nail into the coffin of Theresa May’s deal, insisting it will not back it under “any set of circumstances”.

The prime minister was warned her allies in government will not change its mind – even as talks continue – appearing to rule out a third ‘meaningful vote’ taking place on Friday.

Some in Downing Street still harbour hopes of a DUP switch that would persuade more Brexiteer Tories to back the agreement and enable to get over the line in the Commons.

But Jim Wells, a former DUP deputy speaker of the Northern Ireland assembly, said any deal with the trap of the Irish backstop was “totally unacceptable” to all Unionists.

“You will not find a single public representative in the province who can countenance leaving under the terms of the backstop – and that hasn’t changed since 7 December 2017,” he told BBC Radio 4’s Today programme.

And he added: “We would damage irrevocably our trading relationship with our biggest market, which is the rest of the UK, and we are sitting in a waiting room for constitutional change. And we simply can’t accept that.

“I can’t see any set of circumstances where the DUP would sign up to any agreement which would leave us in this waiting room for change – we just can’t do it.”

Mr Wells insisted the UK and the EU would have to agree legal changes to create an escape route from the backstop – something Brussels has repeatedly refused to do.

However, in a separate interview, Arlene Foster, the DUP leader, left open the possibility of backing a softer Brexit if it emerges from the “indicative votes” process, which resumes on Monday.

“We want to see Brexit delivered. But if it's a Brexit that keeps the whole of the United Kingdom together, that is the most important thing,” she told Irish state broadcaster RTE.

If No 10 abandons hopes for a third vote – something John Bercow will block anyway, unless it is on a changed motion – Ms May’s options will narrow dramatically.

Some believe she will have to head to Brussels next week to ask for a long extension to the Article 50 process, even though it will require participation in the European Parliament elections.

However, it is unclear whether the EU will say yes without the Commons coalescing around an alternative deal, such as staying in the customs union – perhaps with a Final Say referendum to confirm it.

The threat of a no-deal Brexit on 12 April remains real, even though Ms May said it could not happen without MPs’ agreement. A crash-out was rejected by 240 votes last night.

Oliver Letwin, the architect of the indicative votes, said he still believed a consensus could be reached in a second round on Monday.

But he warned the UK was heading for a crash-out Brexit, saying: “At some point or other, we either have to get her deal across the line, or accept that we have to find some alternative, if we want to avoid no deal on the 12th [of April], which I think at the moment is the most likely thing to happen.”