Amid growing anger over her leadership, Prime Minister Theresa May struck a defiant tone Monday, insisting that Brexit negotiations are 95 percent done and that the final product will amount to a good deal for Britain.

May has faced harsh criticism from Brexit hard-liners, who say she is ceding control to the European Union; from political rivals, who say she has lost command over her party; and from those who want to remain in the E.U. and say she is denying the people of Britain control over their future.

“The shape of the deal across the vast majority of the withdrawal agreement is now clear,” May told Parliament, adding that her government has been making progress in talks with negotiators across the English Channel.

But that last 5 percent is no small thing. Indeed, how to avoid a hard border between Northern Ireland, which is part of the United Kingdom, and Ireland, an E.U. member, is “a real sticking point,” May acknowledged.

It has been this way for months.

“It’s basically Groundhog Day every single day,” said Rob Ford, a politics professor at the University of Manchester. “The Irish border? How do we solve it? Who knows? Everyone has a big row. Wake up the next day, like Bill Murray, you hear the same song.”

The problem is becoming more urgent, however, because Britain is set to leave the E.U. in just five months. If the two sides do not strike a divorce deal, Britain risks exiting without one — a doomsday scenario that could have serious implications for the economy and daily life.

Two years after Britons voted 52 percent to 48 percent in favor of leaving the E.U., Brexit continues to be a highly divisive issue.

On Saturday, thousands of people took to the streets to protest Brexit and call for a “people’s vote.” Organizers estimated that 700,000 people turned out, which would make it the largest protest in Britain since the start of the Iraq War. Still, it was noteworthy that none of the featured speakers were leading members of the ruling Conservative or opposition Labour party.

May further angered her critics in recent days when she indicated she would be open to extending the Brexit “transition period” beyond the proposed timeline of December 2020. That is deeply unpopular with the hard-liners, who say it would leave Britain in the position of a “vassal state,” and with those desperate to end the uncertainty associated with Brexit.

“The whole country is waiting for a plan that works for Britain, not another fudge, kicking the can down the road to keep her party in power,” Jeremy Corbyn, leader of the Labour Party, said in Parliament on Monday.

Meanwhile, May also must contend with allegations of plots against her.

In the weekend British papers, unnamed lawmakers were quoted using savage imagery to describe a possible coup, with some saying that “assassination is in the air” and that May should “bring her own noose” to an upcoming meeting.

But the remarks may have backfired. Their tone — if not the substance — was condemned by politicians from all parties.

Nicola Sturgeon, the Scottish first minister, said: “Few disagree with her more than I do, but language like this debases politics. Get a grip, Tories.”

Many of those who took exception to the remarks referenced Jo Cox, the Labour member of Parliament who was killed in 2016 by a right-wing extremist. There were also calls to unmask the lawmakers who made the purported comments.

Most analysts say it is unlikely that May will be ousted just yet. Forty-eight Conservative lawmakers have to submit the letters required to trigger a vote of no confidence, but many predict that — in the current climate at least — May would probably win that vote.

And despite all the mudslinging from the sidelines, there is not an obvious successor. Boris Johnson, the former foreign secretary, may be hugely popular among the Conservative grass roots, but many doubt that his preferred Brexit deal would win the support of Parliament.

“If you got the poisoned chalice of negotiating Brexit, you might as well keep Theresa May as prime minister, because there isn’t a successor who could unite the party,” said Jonathan Tonge, a professor of politics at the University of Liverpool.

“A Boris Johnson-led administration would hit the buses within weeks,” Tonge said. “Theresa May is at least still managing to juggle the plates.”