The Democratic Unionist Party is not prepared to back Theresa May’s Brexit deal unless it is convinced it can pass a House of Commons vote, HuffPost UK understands.
The support of the Northern Irish party, which props up the prime minister’s government, is seen as the key to unlocking the backing of Tory Brexiteers looking for a reason to lend their support to her agreement.
But ministers’ talks with the DUP have stalled, with one insider remarking that they “can’t see a breakthrough at present”.
The DUP is keen to strike a deal in which the government will provide enough legislative and legal assurance to convince the party that Northern Ireland’s place in the union is not threatened by the controversial Irish backstop.
However, HuffPost UK has learnt that even if ministers prevail, the party will be reluctant to compromise unless they believe there are enough Tory and probably Labour MPs willing to help May’s deal pass.
Like many MPs, the party does not want to waste valuable political capital striking a deal with the PM, only for her withdrawal agreement to be voted down again.
But it could prove a difficult situation for Downing Street, with observers believing Tories especially will not move until the DUP does.
“Just as other parties have been reluctant to switch their votes, you would only expect the DUP would take the same approach,” a source said.
The talks are understood to include discussions around a Stormont ‘lock’, which would see Northern Ireland’s laws remain in line with the UK and begin to address concerns about additional checks taking place between the province and the mainland.
The DUP has also declined to deny reports it is seeking a seat at the table in future trade negotiations.
The talks involve a rolling cast of DUP MPs, including Westminster leader Nigel Dodds, as well as lawyers Gavin Robinson and Emma Little-Pengelly, whose expertise is being called on in matters of legal detail, and others.
On the government side, May’s de facto deputy David Lidington, environment secretary Michael Gove and chief whip Julian Smith are taking a lead.
But the presence of Philip Hammond, the chancellor, in negotiations is not believed to be a precursor to the DUP’s support being bought off by a government pledge to pump money into Northern Ireland.
Instead, the party views the issue of the union as too fundamental to be dictated by money and does not believe voters in Northern Ireland will accept it backing down simply in exchange for additional funding.
The DUP remains concerned about the backstop – a fallback plan to maintain an invisible border between the Republic and Northern Ireland if future talks between the UK and EU fail to produce a long-term trade agreement – primarily because it would see Northern Ireland treated differently to the rest of the UK.
Meanwhile, Tory Brexiteers are worried that it could trap Britain inside a customs union with the EU, which would leave it unable to sign comprehensive free trade deals around the world.
May’s attempts to secure changes from the EU that would allow for a guarantee that the backstop would not be permanent failed, with attorney general Geoffrey Cox warning the risks of the arrangement “remained unchanged”.
Cox is now thought to be working on an update to his legal advice to assure the DUP and Brexiteers that the UK could leave the backstop in exceptional circumstances under international law – although this has so far failed to move the dial substantially in Westminster.