Cabinet minister Liam Fox has urged Tory Remainers to keep an “open mind” after they threatened to rebel over the approach to membership of a customs union.

The International Trade Secretary suggested the Brexit “war cabinet” on Thursday has agreed proposals that would deal with their fears.

Former minister and leading Tory rebel Anna Soubry had warned she had 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.

Mr Fox 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.”

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.”

Mr Fox said the Government wanted to sign new international trade deals during the transition period that could be implemented afterwards.

Asked if a deal would be ready with the US, Australia and other countries by the time the UK by the end of the implementation period, he replied: “We have got 14 working groups working with 21 different countries at the present time. We want to be able to take those negotiations as far as we can during that implementation period.”

Labour deputy leader Tom Watson said the party had not made a decision on how it would vote if the 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.”

Theresa 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: “On Thursday, I told the Cabinet committee at Chequers that the deal we negotiate with the EU must present an ambitious future for our great country.

“Next week I will present the committee’s conclusions to an additional session of the full Cabinet before travelling to the North East on Friday to give a speech setting out this Government’s vision of what our future economic partnership with the European Union should look like.

“Delivering the best Brexit is about our national future, part of the way we improve the lives of people all over the country.

“So I concluded the meeting by reminding the committee that the decisions we make 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.”

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 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.

“It’s not about propping up the Government, it’s about implementing a decision of the people.

“It’s all hype. The Government’s got a majority on this. 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.”

Mr Field and Labour MP Stella Creasy clashed in a heated exchange about the direction of Brexit and the cost to the economy.

Ms Creasy said: “Frank, please don’t get on Boris’s bus. What you are saying is that somehow we will get money back. All the evidence shows us that any money you might get back will be dwarfed by what we will lose.”

Mr Field hit back: “Are you going to rat on the people’s decision to leave?”