May was due to meet senior ministers to discuss her Brexit bill as plans to put it to a vote in Parliament were thrown into doubt. May's fate looked sealed after the resignation late Wednesday of House of Commons leader Andrea Leadsom, who said she could not support May's European Union withdrawal bill.
Leadsom had been due to announce in the Commons on Thursday when a vote on the bill would be held. But Leadsom said May's Brexit plan did not "deliver on the referendum result" that saw voters in 2016 opt to leave the EU.
"No one has wanted you to succeed more than I have, but I do now urge you to make the right decisions in the interests of the country, this government and our party," Leadsom wrote in a resignation letter to May.
May moved quickly on Thursday to replace Leadsom with former Treasury minister Mel Stride. But she was forced to delay plans for the bill, which is May's fourth and likely final attempt to secure Parliament's backing for her Brexit blueprint.
The draft legislation contains measures aimed at winning support from the opposition, including a promise to let Parliament vote on whether to hold a new EU membership referendum. That concession was the final straw for many Conservative lawmakers and ministers, who are urging May to scrap the bill.
May previously announced that it would be published on Friday and put to a vote during the week of June 3. But there was no mention of the bill on the parliamentary schedule for that week, published on Thursday.
Government whip Mark Spencer told lawmakers that "we will update the House on the publication and introduction of the Withdrawal Agreement Bill" when lawmakers return from an 11-day recess on June 4. The political turmoil weighed on the pound, which fell to $1.2601 on Thursday, its lowest point against the dollar since early January.
Meanwhile, the number of Conservative lawmakers calling on May to resign was growing. The party's legislators want May to agree on Friday that she will quit, triggering a Conservative leadership contest. If not, they are likely to try to topple her.
"I want her to give a timetable for when she will go," said Geoffrey Clifton-Brown, treasurer of the committee that oversees Conservative leadership races. He said that if she did not set a departure date there would be "overwhelming pressure" for a no-confidence vote in her.
If May quits as party leader she will likely remain as caretaker prime minister for several weeks while Conservative lawmakers and members vote to elect a successor. May's spokesman, James Slack, insisted she would still be in the post when U.S. President Donald Trump comes to Britain for a June 3-5 state visit.
"She looks forward to welcoming the president," he said. May became prime minister soon after the June 2016 EU membership referendum, and has spent her entire term in office trying to deliver on that decision.
She seemed close to success when she struck a divorce agreement with the EU late last year. But lawmakers have rejected it three times, and Britain's long-scheduled departure date of March 29 passed with the country still in the bloc.
Many Conservatives blame May for the delay, and believe she is now an obstacle to Brexit. They want her replaced with a more ardent Brexiteer such as the former foreign secretary Boris Johnson. May says another leader will not be able to strike a better deal with the EU. On Wednesday she urged lawmakers to support her Brexit bill, saying that if they reject it "all we have before us is division and deadlock."
If May stays on until next week, pressure is likely to increase when results come in from this week's elections for the European Parliament, with Conservatives expect to receive a drubbing. Many British voters on both sides of the Brexit debate look set to use the election to the EU legislature to express displeasure over the political gridlock.
Opinion polls show strong support for the single-issue Brexit Party — largely from angry former Conservative voters — and for pro-EU parties including the Liberal Democrats and the Greens. The election is being held on Thursday in Britain, but results won't be announced until all 28 EU countries have finished voting late Sunday.
British newspapers on Thursday were unanimous in declaring that the end was nigh for May. The Conservative-backing Daily Telegraph said in an editorial that "either Mrs. May must go as soon as humanly possible, or the Conservative Party must finally remove her."
The Daily Mail, which has been supportive of May, said that "despite her valiant efforts to deliver an honorable Brexit, she has finally run out of road."
Carlo Piovano contributed to this story
Follow AP's full coverage of Brexit at: https://www.apnews.com/Brexit