If Theresa May has a genius, it is for survival. A day that the British prime minister started battling a political crisis over Brexit that could have destroyed her, ended with May flying to a G-7 summit relatively unscathed.

But while May escaped the immediate danger, a fresh storm blew up over secretly taped comments from her colorful Foreign Secretary, Boris Johnson. Speaking at a private dinner, he attacked her strategy, predicted a Brexit “meltdown” and lifted the lid on the bitter divisions inside the Cabinet.

Johnson’s outburst—leaked to Buzzfeed—shows how for the prime minister leading a fragile government and encircled by critics, victory is only ever temporary.

It is a year since May’s gamble on an early election backfired disastrously, costing her Conservatives their majority in Parliament and putting her own future—and that of Brexit—in doubt. Many on her own side thought she’d be gone within weeks of the June 2017 vote. But she’s come through a succession of crises and remains in office, despite threats and plots to oust her.

Thursday’s drama focused on May’s fractious relationship with her euroskeptic Brexit Secretary, David Davis, once seen as a leading candidate to replace her. He was said to be ready to quit in protest at May’s plans for the U.K.’s future tariff regime. He was furious that she was proposing an open-ended commitment to stay in European customs rules in order to avoid a hard border with Ireland.

More Complex

After two tense meetings, Davis’s allies trumpeted a victory, claiming he had persuaded her to insert an end date to the plan so the U.K. would not be bound forever by European trade law.

But when the proposal was published, it was clear that the truth was more complex. Government officials privately admitted it was a “fudge.” There was no firm end-date to the plan, only an aspiration that it “should be” time limited, and that the government “expects” it to last no longer than until December 2021.

This was enough for Davis to claim a face-saving victory, but it didn’t impress other Brexit supporters in May’s party. “I am very concerned that by the time we have negotiated this with the EU we will have a never-ending vassal state status,” said Nigel Mills, a Brexit backing Conservative member of Parliament. “That is not something I think that this country could possibly sign up to.”

Mills said the government must be much clearer about its long-term plan for a realistic new customs deal with the EU, so May’s temporary backstop option isn’t needed. At the moment the government is “scratching around hoping to find a magical solution that isn’t there,’’ he said.

Asked twice by reporters accompanying May to the meeting of G-7 leaders in Canada if that date is a cast-iron guarantee, she declined to give that assurance. May said the measure may never have to be used and she expected the “end-state” customs agreement with the bloc to be in place by December 2021 “at the latest.”

“We expect that we will actually be able to have that end-state customs arrangement in place at the very latest by December 2021, but our focus, obviously, is going to be on making sure that we get that agreement which we have all agreed—and others are agreed—is the best way to ensure that we get the right relationship between the U.K. and the EU for trading,” she said.

‘Irrelevant to Reality’

Whilst May and her allies tried to convince Tories to back her temporary customs arrangement, European officials were privately unimpressed.

One diplomat described the government’s paper as a “joke,” and another as “backtracking.” A third said the EU would never be able to accept it without far greater clarification. “It’s a fudge that satisfies her cabinet, but it’s a fudge that’s practically irrelevant to reality,” said the first diplomat, speaking on condition of anonymity.

Michel Barnier, the EU’s chief Brexit negotiator, was more polite, but hardly encouraging. He is due to give a news conference Friday before holding face-to-face talks with Davis on Monday. By then, May will be pitched into a new domestic political drama: trying to get her key Brexit law through a potentially hostile Parliament.