Theresa May is facing a major House of Commons rebellion over giving Parliament a right to stop her from walking away from the European Union in two years’ time without a deal.
Peers are expected to vote to amend legislation triggering the start of Brexit talks on Tuesday to force the Government to give MPs and peers a “meaningful vote” on the outcome of her negotiation.
That comes after members of the House of Lords voted this week to amend the legislation to force the Prime Minister to guarantee the rights of European Union nationals after Britain leaves the EU.
Downing Street has made clear that it expects MPs in the House of Commons to overturn the changes in the Lords in a series of votes in 10 days time, on March 13 and March 14.
Senior Remain-supporting Tories have told The Daily Telegraph that they expect at least 20 Tory MPs to vote with Labour and the Liberal Democrats to support the meaningful vote amendment.
The amendment would stop Britain leaving the EU until the Commons and Lords have approving a final draft of the terms of Britain’s decision to leave the EU.
One MP said that the rebels were set to back Mrs May and overturn the EU nationals amendment because of the Prime Minister’s assurances of an early deal on EU nationals.
Anna Soubry, a Conservative MP, added: “The meaningful vote is absolutely critical, it's the deal breaker. I think there is a very good chance that we could get more than the seven we had.
“I just want us to behave in a grown up way. People have to remember 48 per cent did not vote to leave the European Union.”
David Davis, the Exiting the EU secretary, said on Thursday that the Government had hoped to get a deal for EU nationals in the UK and Britons on the Continent.
Mr Davis said: “If we had had our way, we would have actually got an agreement in principle at least in December … but we couldn’t get everybody to agree at that point.
“It will be the first thing on our agenda. I would hope that we would get some agreement in principle very very soon, as soon as the negotiation process starts.”
The news came as it emerged that LibDem peers have ordered 90 sleeping bags and camp beds to prepare for a long night of “ping pong” as MPs and peers battle over the contested changes.
This could in theory see the legislation pass back and forth between the House of Commons and House of Lords until a position emerges on the Bill.
The LibDems which have 102 peers and nine MPs spent yesterday discussing their strategy.
One senior party strategist said: “We are planning for every eventuality and planning for all night sessions.
“If that means pizza and food delivery at 3am then so be it. We have plans in place for sleeping bags and beds for our peers.
“We think this matters and Tim Farron has said we will go through the lobbies time after time to defend the rights of 3.3million EU nationals who live and have made their home here.
“We are also committed to fighting tooth and nail to give the people a final say on the deal.”
Separately it emerged that Gina Miller, who brought the lawsuit that forced Mrs May to get parliamentary approval for her Brexit plans, is considering another legal challenge if Parliament is not given a full vote on the final deal.
It also emerged that the EU might be willing to accept that the UK’ s share of EU assets should be offset against its left-over liabilities in the exit bill, which could be paid off over several years.