Brexit Secretary Dominic Raab has sped to Brussels ahead of the upcoming crucial EU summit.
He will meet the EU’s chief negotiator Michel Barnier on Sunday afternoon as the British government admitted there will still “several big issues” to be resolved – including the Northern Ireland backstop.
A Department for Exiting the European Union spokesman said it was “jointly agreed that face-to-face talks were necessary”.
It comes as Theresa May faces open revolt on the Tory benches and possible cabinet resignations over her proposed Brexit deal.
The issue of the border between Northern Ireland and Ireland is one of the last remaining obstacles to achieving an agreement.
The two sides are wrangling over the nature of a “backstop” to keep the frontier open if a wider UK-EU trade arrangement cannot resolve it.
The EU’s version of the backstop, which would see just Northern Ireland remain aligned with Brussels’ rules, has been called unacceptable by May and is loathed by the DUP.
May’s counter-proposal is for a “temporary customs arrangement” for the whole UK.
But Tory Brexiteers fear this becoming an open-ended position which would prevent free trade deals with countries around the world.
The Cabinet will meet on Tuesday, ahead of the crucial EU summit which begins on Wednesday.
Speculation about possible resignations has centred on Andrea Leadsom, Penny Mordaunt and Esther McVey.
Former Brexit secretary David Davis said today the plan was “completely unacceptable” and urged Cabinet ministers to “exert their collective authority”.
Health Secretary Matt Hancock sought to play down speculation that some of his colleagues might quit.
But he was unable to say whether a fixed deadline for any customs arrangement would be written into a deal with Brussels.
Hancock told the BBC’s Andrew Marr Show: “There are different ways that you can make sure that something is credibly time limited and that’s what I want to see.”
Tory vice chairman James Cleverly told Sky News’ Sophy Ridge on Sunday that Cabinet ministers should use their position to influence Brexit policy rather than resign.
“They should use that position to put their ideas forward, I would suggest that’s a much more constructive and helpful way of influencing the direction of the negotiations with the EU,” he said.
It comes as research suggested May will need at least 14 Labour MPs to vote in favour of her deal if she is to win the Commons vote.