Prime Minister Theresa May is facing a decisive battle with her cabinet over the U.K.’s future ties to the European Union, in a showdown that threatens to throw Brexit talks into disarray.

May’s top team of ministers is due to finalize the U.K. blueprint for its partnership with the EU at crunch meeting in her Chequers country residence Friday, but a group of seven pro-Brexit ministers are privately pushing for her to tear up her plans.

In an extraordinary move, the rebel cabinet ministers met in Foreign Secretary Boris Johnson’s offices late Thursday to coordinate their opposition to the premier’s policy on linking tariffs and goods regulations closely to those of the EU.

For her part, May is also ready for a fight, one of her senior allies said.

“We have a great opportunity –- and a duty,” May said ahead Friday’s cabinet meeting. “This is about agreeing an approach that delivers decisively on the verdict of the British people -– an approach that is in the best interests of the U.K. and the EU, and crucially, one that commands the support of the public and Parliament.”

The clash comes at a critical moment in the Brexit process. The EU is pushing May to produce a workable plan for the future trade relationship, warning that time is running out for reaching an agreement before exit day in March.

Betrayal

May has summoned her cabinet to the all-day meeting at Chequers with the goal of securing their support for an overarching plan—in the form of a government “white paper”—to take to the EU.

Brexit backers among May’s top team are worried that she’s betraying their vision of a clean split with the bloc that will enable Britain to strike free trade deals with countries around the world such as the U.S.

The Brexit backers’ concerns include May’s plan for a customs deal in which the U.K. collects the EU’s tariffs, and a trade regime that binds British regulations on goods and agri-food to European rules forever.

“If true, this would be a complete breach of Theresa May’s manifesto commitment” to leave the EU single market, customs union and the bloc’s court, said Owen Paterson, a former Cabinet minister and Brexit campaigner. “We would be out of Europe but still run by Europe.”

The seven “Brexiteer” ministers held constructive talks in Johnson’s office and want to work through their differences with May, according to people familiar with the discussions. As well as Johnson, the ministers present in the Foreign Office included Brexit Secretary David Davis, Development Secretary Penny Mordaunt, Work and Pensions Secretary Esther McVey, Andrea Leadsom, the Commons leader, and Michael Gove, the environment secretary, according to a person familiar with the matter.

Fox left the meeting of Brexiteers for private talks with May over a drink in her apartment in Downing Street at which he raised a number of issues. She gave him a personal assurance that Brexit would allow Britain to strike free trade deals around the world, a person familiar with the matter said. Fox now expects May on Friday to clarify the points they discussed.

Merkel Unhappy Too

Pro-Brexit ministers are angry that May’s aides devised the plan without consulting senior cabinet members who were supposed to be working on a customs solution. It has also received a chilly response from German Chancellor Angela Merkel’s government.

A draft of May’s proposal was leaked Thursday, including a line saying it wouldn’t “allow the U.K. to accommodate a likely ask from the U.S. in a future trade deal.” That upset the “Brexiteers” in the cabinet who have made an American trade deal one of their key aims.

May’s office hit back at the leak, with one official saying the line had been selectively quoted. The prime minister’s spokeswoman Alison Donnelly said May remains committed to seeking an agreement with America.

“It is categorically untrue to suggest that we will not be able to strike a trade deal with the U.S.,” she said.

According to one of May’s Cabinet allies, who spoke on condition of anonymity, the prime minister views other kinds of relationships with the EU—typically ones modeled on Canada’s or on Norway’s—as either unacceptable or unworkable.

Quitting without a deal, as proposed by some in May’s Conservative Party, would leave the U.K. in a bitter and acrimonious relationship with the EU just as it was trying to sort out side-deals in areas such as aviation that Britain would still need.

While May’s delay in making a decision on Brexit has been characterized as weakness, and left some in her government wondering if she would ever make a decision, the minister said this had been a strategy aimed at leading her internal opponents to the same conclusion as she had come to regarding the viable options.

At Chequers, the minister said, she was prepared to push for what she wanted, even if it meant upsetting people. It’s a political convention in the U.K. that ministers who feel they cannot sign up to government policy are expected to resign from the cabinet.