Theresa May appeared to be heading for a major parliamentary defeat on her revised Brexit deal on Tuesday, after Eurosceptic MPs seized on an admission by the UK’s attorney-general that the country could be unable to leave the controversial Irish backstop without the EU’s consent.
The British prime minister had hoped that additional assurances, agreed with the European Commission in Strasbourg late on Monday, would win over Northern Ireland’s Democratic Unionist party, as well as pro-Brexit Tories, to allow her to overturn the 230-vote defeat on her original deal in January.
But on Tuesday afternoon the DUP said that “sufficient progress has not been achieved at this time”. A party official confirmed its 10 MPs would vote against the government.
Large numbers of the pro-Brexit European Research Group of Tory MPs are also expected to vote against the deal, after a group of lawyers advising the faction said the government had failed to meet its own tests.
Mrs May warned MPs they were facing a “very clear” choice between leaving the EU with a deal or not leaving at all.
But although a series of Conservatives who voted against her original deal in January announced they would now back it, there was little or no sign of the large-scale shift that would allow her to claim victory. More than 100 MPs — principally pro-Brexit Conservatives — would need to swing behind Mrs May for her to prevail.
Instead, Eurosceptics reacted to advice from Geoffrey Cox, UK attorney-general, which warned that, despite the new assurances, Britain faced an “unchanged” risk of being trapped in the so-called backstop to avoid a hard Irish border.
Mr Cox, himself a Brexiter, concluded in previous legal advice in November that the backstop could endure “indefinitely”, enraging Eurosceptics who fear the arrangement would lock Britain into a permanent customs union with the EU and prevent the UK from striking trade deals after Brexit.
Some MPs had expected the attorney-general to soften his position after the latest negotiations between the UK and Brussels, in which he was a key player.
In a three-page letter to Mrs May published on Tuesday, Mr Cox did say that the new Brexit assurances “reduce the risk that the United Kingdom could be indefinitely and involuntarily detained” in the Irish backstop because of bad faith on the EU’s part.
But he added that “the legal risk remains unchanged” that, if there were “intractable differences” between the UK and the EU, rather than bad faith by the bloc, Britain would have “no internationally lawful means of exiting” the backstop without the EU’s agreement.
The pound fell 1 per cent against the US dollar, to $1.3020 just after the release of Mr Cox’s letter, more than wiping out a rally late on Monday after Mrs May unveiled the Brexit assurances with the EU. Sterling had traded as high as $1.3288 after Monday night’s New York close.
If Mrs May’s deal is defeated on Tuesday, MPs will vote on Wednesday whether to rule out a no-deal Brexit and then on whether to request an extension to Article 50, the EU’s formal divorce process, beyond the scheduled exit date of March 29.
It is unclear what substantive plan parliament would then agree to, with hardline Eurosceptics, hardline Europhiles and the Labour leadership all seeking different outcomes.
The European Commission president Jean-Claude Juncker said on Monday that there would be no further negotiations if the deal were rejected. Mrs May’s position would come under pressure, although under Conservative party leadership rules she cannot be formally challenged until December.
Government supporters emphasised the more upbeat parts of Mr Cox’s advice, including his “political judgment” that it was “highly unlikely” that an alternative to the backstop would not be found.
The attorney-general, who was little-known in British politics until his appointment to the cabinet last year, had insisted he would not deliver politically convenient advice.
“I have been a barrister for 36 years, and a senior politician for seven months,” Mr Cox told the Mail on Sunday newspaper last week. “My professional reputation is far more important to me than my reputation as a politician.”
In parliament on Tuesday Dominic Grieve, the Europhile former Conservative attorney-general, praised Mr Cox for “speaking truth to power”.
After rejecting Mrs May’s original Brexit deal in January, MPs passed a motion calling on Mrs May to “replace” the backstop. The legal documents presented by the EU and the UK on Monday evening fell short of that goal. Nor did they provide a fixed end date for the backstop, or a unilateral exit mechanism, which Mrs May had suggested could be negotiated.