British Prime Minister Theresa May faces a no-confidence vote from her Conservative Party lawmakers Wednesday, the latest fallout from her handling of the process to withdraw Britain from the European Union.

If a majority of Conservatives in the House of Commons vote against May, she will have to step down as prime minister. But if she survives the confidence vote, another could not be called for one year.

May vowed to fight the vote “with everything I’ve got,” and said changing leaders now would jeopardize the Brexit process.

Ian Lavery, chair of the main opposition Labour Party, said in a statement that “May’s weakness and failure has completely immobilized the government at this critical time for the country.”

Conservative official Graham Brady announced the vote Wednesday, saying the requirement of at least 15 percent of party lawmakers requesting it had been reached. He said the result of the vote would be made public “as soon as possible.”

Britain is due to exit the EU on March 29, 2019 as the result of a 2016 referendum. The two sides worked out an agreement on the divorce terms after lengthy negotiations, but it must be approved by Britain’s parliament and earlier this week May canceled a planned vote during which it seemed certain to fail.

May has subsequently been trying to save the agreement through talks with European leaders. But EU officials have been firm about their lack of desire to renegotiate the terms.

EU Council President Donald Tusk said after what he called a “long and frank discussion” with May on Tuesday that it is clear the other EU members want to help resolve the situation, but that “the question is how.”

Tusk has called a meeting of EU leaders to discuss Brexit on Thursday, including the possibility March 29 will come with no agreement in place.