SENIOR Tories are forecasting their party is facing a permanent split over Theresa May’s plan for a softer Brexit.

The prediction was initially made by former minister Steve Baker and supported yesterday by Scottish Conservative MP Ross Thomson.

In a round of interviews Baker said he was “gravely worried” for the future of his party with up to 80 Tory backbenchers prepared to vote against it.

“We are reaching the point now where it is extremely difficult to see how we can rescue the Conservative Party from a catastrophic split if the Chequers proposals are carried forward,” he said.

“It is absolutely no pleasure whatsoever to me to acknowledge that, but I look at the mood of colleagues and the mood of the Conservative Party in the country and I am gravely concerned for the future of our party.”

Posting a link to a TV interview with Baker, Thomson, said: “I agree with @SteveBakerHW. The #ChequersPlan is an unworkable fudge which is not supported by leavers or Remainers. Oh and the EU too. If it’s pushed through the Conservative party will fracture. There’s still time to #ChuckChequers, deliver a free trade deal and unite the party.”

Baker is the former chairman of the Brexit supporting European Research Group (ERG), which plans to publish its own proposals for Brexit ahead of the Conservative Party conference which starts later this month.

He said the lack of support for May’s plan, which would involve the UK accepting a common rule book for trade in goods, among Tory MPs left her with a “massive problem” in the run-up to next month’s Conservative conference.

Downing Street yesterday delivered a withering put down to Boris Johnson’s claims that May’s Brexit plan has left the UK strapped to a “suicide vest”.

In the latest sign of increased tension between the Prime Minister and her former Foreign Secretary, Number 10 said they would not give “further oxygen” to his remarks,

Writing in the Mail on Sunday, the former Foreign Secretary said the PM’s plan was a “humiliation”, while “Brussels gets what Brussels wants”.

His remarks sparked a furious backlash from senior Conservatives, who said he had gone too far in his criticism.

Tory Foreign Affairs Committee chair and ex-soldier Tom Tugendhat suggested Johnson should “grow up”.

A spokesman for May said: “This isn’t language the Prime Minister would choose to use.

“I don’t plan on giving this article further oxygen.”

Meanwhile Justice Secretary David Gauke told the BBC Radio 4 Today programme: “There is an overwhelming majority within the Conservative Party that we respect the referendum result, that we implement it in such a way as to respect the integrity of the United Kingdom and the Good Friday Agreement and ensure that we are in a strong position to grow the economy in the years ahead.

“There isn’t an alternative credible plan out there. I think that it is absolutely right that the Cabinet and the parliamentary party backs the Prime Minister. In challenging circumstances she is the right person to deliver the right deal for this country.”

Former Tory cabinet minister Nicky Morgan, who campaigned for Remain, urged May to appeal to MPs across the political spectrum to come behind a compromise plan for Brexit. “I believe the vast majority of people in the middle, both in the Conservative parliamentary party and the country at large, want to see an ongoing trading relationship with the EU. That is why Chequers was very welcome,” she said, rejecting suggestions she could quit the Tory Party if Johnson became leader.