Tory Remainers preparing to rebel to force the Government to sign up to a customs union have been urged to fall into line by senior figures in the party.
Labour has said it wants Britain to be part of a customs union with the European Union after Brexit.
Theresa May was reportedly warned during talks at Chequers on Thursday that the Government could collapse if Europhile Conservative MPs join forces with Labour.
Leading Tory rebel Anna Soubry has warned she has cross-party support for a new amendment to the Government’s trade bill that would mandate the UK to form a customs union with Brussels after Brexit.
The former minister indicated she was ready to pull back if the Prime Minister announces measures that would amount to a customs agreement when she makes a speech on Brexit on Friday.
Ms Soubry told BBC Radio 4’s The World at One: “I’m told and I’ve read in newspapers that I won’t need to put my amendment or any other amendments to the vote because Theresa’s going to say sufficient to avoid that.
“It’s absolutely beholden now on the Government to get itself in the right place. I’m not quite sure it’s got there, but lets wait and see where we are on Friday because if they have gone into the right place we can get on with it.”
International Trade Secretary Liam Fox urged Tory Remainers to keep an “open mind” and suggested the Brexit “war cabinet” on Thursday has agreed proposals that would deal with their fears.
He told BBC One’s The Andrew Marr Show: “I would say to my colleagues that Theresa May has kept a broad range of views on the European issue for a reason.
“We sat down with those differing views, we set out the issues, we looked at the options and we came to an agreement that we are all happy with.”
Liam Fox (Jeff Overs/BBC)
He added: “I hope that they will have an open mind and listen to what the Prime Minister says because I think that what the Prime Minister will set out will deal with a lot of the reservations that they have.”
Asked if legislation was being delayed because the Government would lose, he replied: “We want to persuade our colleagues of the merits of our argument before we take the bill forward.”
Tory former leader Iain Duncan Smith warned potential rebels against challenging the Government.
He told BBC One’s Sunday Politics: “I say to my colleagues, who might want to change some of this, just be very careful on this one because you’re being invited into a Labour party tactical game which will actually end up in real damage to the UK.”
Labour deputy leader Tom Watson said the party had not made a decision on how it would vote if a Tory rebel amendment on a customs union is put to the Commons.
“Obviously, their position is very close to Labour’s position,” he told ITV’s Peston On Sunday.
“I hope we can get to a point where the Government listen to us, they understand it is reckless to rule out any form of customs union.”
Mrs May has insisted Brexit is the beginning of a “bright new chapter” for Britain and the country’s best days “really do lie ahead of us”.
The Prime Minister will hold a special Cabinet meeting on Thursday ahead of her keynote speech on Britain’s exit from the European Union in the North East the day after.
She said the decisions taken now will “shape this country for a generation”.
“If we get them right, Brexit will be the beginning of a bright new chapter in our national story, and our best days really do lie ahead of us,” she said.
Labour MP Frank Field, who backed Leave, said remaining in a customs union or the single market would be a “deceit”, and dismissed suggestions that Ms Soubry could defeat the Government.
“The idea Anna Soubry is going to lead all these people into the Labour lobby is just fairytales. But we will see on the night. The Government will win comfortably in double figures,” he told BBC One’s Sunday Politics.