Theresa May warned she will betray Brexit if she accepts amendments to remain in a customs union

Theresa May has been warned she would be betraying the electorate if she accepts amendments which would keep Britain in a customs union after Brexit.

Tory MPs have urged the Prime Minister to stick to her guns after a group of five rebels proposed changes which would force the UK to remain in a customs union with the block.

It came after Anna Soubry and Labour’s Chuka Umunna tabled a new amendment to the trade bill, which called for MPs to support the “implementation of a customs union with the EU” following the UK’s departure.

Brexit-supporting MPs rounded on the amendment within hours, with Tory MP Michael Fabricant describing the proposal as a “total betrayal of what the 52 percent of the electorate voted for”.

Urging Mrs May to stay the course, Mr Fabricant said:  “It will stop us controlling our own borders and prevent us from having an independent trade policy. It will result in Brexit in name, but not in reality.”

Mr Fabricant added that remaining in the Customs Union would prevent Britain from signing independent trade deals after Brexit, adding that the “movers should be ashamed of themselves”.

His comments were echoed by Jacob Rees-Mogg, who said that remaining in the customs union would mean Britain would be forced to remain subject to higher price tariffs on a range of goods.

The clause, which is supported by five Tories including Nicky Morgan, Sarah Wollaston and Stephen Hammond, proposes that the Government would be forced to “take all necessary steps” to secure a trade agreement which “enables the UK to participate after exit day in a customs union with the EU”.

Ms Soubry, who earlier this month urged Theresa May to “sling out” the Brexiteers, said on Friday that she believed “many others” would follow suit and add their names to the amendment.

Mr Umunna is also confident that Labour colleagues will throw their weight behind it, amid reports that Jeremy Corbyn is expected to announce on Monday that the party is now for remaining in the Customs Union.

Such a move could provide a majority for the amendment, resulting in the Government being defeated on key Brexit legislation when it goes comes down to a vote.

“There’s cross-party support for it, the Labour Party position as John McDonnell the Shadow Chancellor has said has been evolving, that has moved,” Mr Umunna said.

“There is no majority in the House of Commons for us not to participate in the Customs Union, that is absolutely clear.”

The dispute threatens poses a serious headache for Theresa May’s Government, which remains firmly opposed to any scenario which would see Britain remain in the current customs arrangement.

It comes after Mrs May’s 11-strong ‘war’ Cabinet finally agreed on their Brexit negotiating position at Chequers on Thursday, during which the customs union was dismissed as an option. 

Answering questions about the meeting, the Health Secretary Jeremy Hunt reiterated that the Government would not accept any deal which included continued membership of the Customs Union.

“We don’t want to be part of the Customs Union,” he added. “We want to be able to negotiate trade deals independently with other countries.

“We wouldn’t have full sovereign control of our destiny as a nation. The Customs Union is one way of getting frictionless trade, but it’s not the only way. What we want is frictionless trade but by agreement between two sovereign bodies.”