LONDON, United Kingdom (AP) — British Prime Minister Theresa May was hunkered down with close allies this morning as she considered whether to give in to relentless pressure to resign or fight on to save her Brexit plan and her premiership.

With her authority draining away by the hour, May delayed plans to get lawmakers to vote on her European Union withdrawal bill — May’s fourth and likely final attempt to secure Parliament’s backing for her Brexit blueprint.

Conservative lawmakers, who increasingly see May as an obstacle to Britain’s EU exit, have given her until Friday to announce her departure date or face a likely leadership challenge.

May has resisted pressure to resign before, and her spokesman, James Slack, insisted she would still be in office when US President Donald Trump comes to Britain for a June 3-5 state visit.

“She looks forward to welcoming the president,” he said.

But 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 withdrawal bill. The draft 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.

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 Thursday to replace Leadsom with former Treasury minister Mel Stride.

But she also delayed the bill, which May previously said would be published Friday and put to a vote during the week of June 3. There was no mention of the bill on the parliamentary schedule for that week that was published 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 today, 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.