Theresa May’s leadership and her plans for Brexit are under pressure after a setback in talks with Brussels.
A hastily arranged meeting between Brexit Secretary Dominic Raab and European Union negotiator Michel Barnier failed to produce a breakthrough, leaving the process on a knife-edge ahead of a crunch summit on Wednesday.
The impasse over measures to prevent a hard border with Ireland has thrown the timetable for reaching a Brexit deal into doubt.
Following the meeting in Brussels, Mr Barnier said that “despite intense efforts” there had been a failure to reach agreement on one of the trickiest aspects of the negotiations.
The surprise announcement of the meeting fuelled rumours a deal was set to be done ahead of this week’s summit of EU leaders.
But after talks which lasted a little over an hour, it was clear that major obstacles remained including the so-called backstop measure to prevent a hard border between Ireland and Northern Ireland after Brexit.
The UK Government said there were still “unresolved issues” relating to the backstop but it remained committed to making progress at the European Council meeting.
But with Mrs May under siege from Tory Eurosceptics and her DUP parliamentary allies, the Government also has a reason to appear to be taking a tough line.
The Prime Minister’s room for manoeuvre is severely restricted, with opposition to both the EU’s proposed backstop and concerns about her own alternative.
The EU version, which would see just Northern Ireland remain aligned with Brussels’ rules, has been called unacceptable by Mrs May and is loathed by the DUP.
Writing in the Daily Telegraph, the DUP’s Westminster leader Nigel Dodds said: “One part of the UK cannot be left behind, bound to rules set in Brussels. The constitutional and economic consequences of such an approach would be catastrophic in the long run.”
Mrs May’s counter-proposal for a “temporary customs arrangement” for the whole UK is viewed suspiciously by Brexiteers who fear it becoming an indefinite position which would prevent free trade deals with countries around the world.
Agreeing to such a measure could trigger a Cabinet revolt and the potential resignation of senior ministers.
Writing in the Daily Telegraph, former foreign secretary Boris Johnson said the backstop idea as a whole should be jettisoned.
“In presuming to change the constitutional arrangements of the United Kingdom, the EU is treating us with naked contempt,” he said.
“Like some chess player triumphantly forking our king and our queen, the EU Commission is offering the UK Government what appears to be a binary choice.
“It is a choice between the break-up of this country, or the subjugation of this country, between separation or submission.”
Ireland’s ambassador to the UK Adrian O’Neill said events in Brussels were a “setback” and could increase the prospect of a no-deal Brexit.
He told BBC Radio 4’s Westminster Hour: “Time is running out, there is no doubt about that. In all member states, preparation for all eventualities are ramping up quite significantly.”
A special EU summit pencilled in for November to sign off a Brexit agreement could instead end up being used as an emergency meeting to discuss “no-deal” plans.
Talks will take place on Monday between DUP leader Arlene Foster and Taoiseach Leo Varadkar, while Mrs May will meet Sinn Fein leader Mary Lou McDonald in Westminster.
The febrile atmosphere in the Tory ranks has seen former Brexit secretary David Davis emerge as a potential successor to Mrs May.
Tory MP Nadine Dorries publicly suggested he could be the leader to deliver the kind of Brexit sought by Eurosceptics.
The Prime Minister’s critics believe the threshold of 48 Tory MPs calling for a no-confidence vote could be passed by Wednesday, depending on events in Brussels.
Allies of Mr Davis said he has been contacted by several Tory MPs urging him to run for the leadership and he is understood to be prepared to take part in a contest.
Ms Dorries backed Mr Davis for the top job, saying: “Getting May out and him becoming an interim leader may be the only way to deliver Brexit and FTA (a free-trade agreement).”