LONDON -- Supportive Cabinet ministers rallied around British Prime Minister Theresa May on Friday, trying to bolster her leadership after a barrage of resignations over Brexit, as rebel lawmakers pushed to force a leadership challenge.

May is battling to save her Brexit plan, and her job, after the draft withdrawal agreement between Britain and the EU sparked fierce opposition from politicians in her Conservative Party who want the U.K. out of the bloc. They say the agreement, which calls for close trade ties between the U.K. and the EU, would leave Britain a vassal state, bound to rules it has no say in making.

A group of hard-core pro-Brexit Conservative lawmakers is working to topple May by submitting letters saying they have lost confidence in her leadership. They are aiming for the magic number of 48 -- the 15 per cent of Conservative lawmakers needed to trigger a challenge to her leadership under party rules. If May lost her job as party leader, she would also lose her position as prime minister.

After a day of conflicting rumours about whether 48 letters had been sent, leading Brexiteer Steve Baker said, "I think we're very close."

He suggested the threshold might be reached "sometime next week."

If May faces a leadership vote and wins, it could strengthen her position, because the rules say she can't be challenged again for a year.

Cabinet Office Minister David Lidington, one of May's chief allies, predicted that "if it does come to a challenge, the prime minister will win handsomely."

"I've seen no plausible alternative plan from any of those criticizing her or wanting to challenge her position," Lidington said.

International Trade Secretary Liam Fox, another Brexit-backing minister, threw May a lifeline by urging rebels to "take a rational and reasonable view of this."

"Ultimately I hope that across Parliament we'll recognize that a deal is better than no deal," he said.

May got another piece of good news when Environment Secretary Michael Gove decided not to follow two Cabinet colleagues and quit over the divorce deal.

Brexit Secretary Dominic Raab and Work and Pensions Secretary Esther McVey quit Thursday, saying they could not support the agreement. Like them, Gove was a strong supporter of the "leave" campaign in Britain's 2016 EU membership referendum.

Gove said Friday that he "absolutely" had confidence in May, adding that he would work with government colleagues to achieve "the best future for Britain." But he did not answer when asked if he supported May's Brexit deal.

May has warned that abandoning her Brexit plan, with Britain's exit just over four months away on March 29, would plunge the country into "deep and grave uncertainty."

She appealed directly to voters by answering questions on a radio call-in show Friday. It was not an easy ride. One caller said May should resign and let a more staunchly pro-Brexit politician take over; another compared her to Neville Chamberlain, the 1930s prime minister who vainly tried to appease Nazi Germany to avoid war.

May stood by her plan.

"For a lot of people who voted 'leave,' what they wanted to do was make sure that decisions on things like who can come into this country would be taken by us here in the U.K., and not by Brussels, and that's exactly what the deal I've negotiated delivers," she said.

The week's political turmoil prompted a big fall in the value of the pound. On Friday, it recouped some gains, trading 0.4 per cent higher at $1.2821, partly on relief that Gove didn't join the others in quitting the government.

But investors and businesses remain worried about the prospect of Britain crashing out of the EU in March without a deal. That could see tariffs on British exports, border checks, restrictions on travellers and workers, and interruption to the supply of goods.

"The markets are looking for a deal," said Michael Baker, a financial analyst at ETX Capital. "They're looking for some sort of agreement, some sort of orderly withdrawal for the U.K. to come out of the European Union."

Simon Kempton of the Police Federation, a union for police officers, said a "no-deal" Brexit could spark protests, and "it's a real concern that those protests might escalate into disorder."

"It's 2018. It's the year that people dial (emergency number) 999 because KFC ran out of chicken," he told Sky News. "If that will happen, imagine what will happen if we start seeing food or medical supply shortages."

EU leaders, who have called a Nov. 25 summit in Brussels to sign off on the draft agreement, were doing their best to refrain from commenting on Britain's political chaos.

But French Finance Minister Bruno Le Maire called some British politicians "liars" who fooled voters into thinking that leaving the EU would be easy and in their interests.

"The truth is that Brexit could end with a nightmare," he said at a conference in Paris on reforming the global trade system.

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Associated Press writer Angela Charlton in Paris contributed.