Britain's Prime Minister Theresa May leaves Downing Street in London, Wednesday, Dec. 5, 2018. Credit: Kirsty Wigglesworth | AP

U.K. Prime Minister Theresa May is calling off a crucial vote in Parliament on whether to approve her Brexit deal, according to a person familiar with the situation.

The vote in the House of Commons to endorse the terms of the U.K.’s split from the European Union was due to be held on Tuesday evening but is now set to be rescheduled, according to the person who declined to be named.

The pound fell to the lowest since June 2017 as market fears about a no-deal Brexit resurfaced after the report that May’s vote will be delayed. U.K. Government bonds rallied, with yields hitting the lowest since August.

May is holding talks with her top ministers to finalize the government’s position, and some are said to think she should go ahead and call the vote as planned for Tuesday.

May will make a statement to Parliament on Brexit on Monday afternoon, House of Commons Speaker John Bercow’s office announced, and she is then expected to confirm her plan to shelve the vote and set out the reasons why.

Two further statements from Cabinet ministers will follow — one from Brexit Secretary Stephen Barclay and another from Andrea Leadsom, who is in charge of the government’s legislative plans.

May’s office publicly insisted the vote was going ahead as recently as 11:20 a.m. on Monday in London but the prospect of an overwhelming revolt from members of Parliament forced the premier to think again.

Graham Brady, chairman of the 1922 Committee representing rank-and-file Tory lawmakers, said May’s decision to pull the vote “is clearly the right thing to do.” He is a key figure in all this because he receives the letters from lawmakers that could initiate a leadership challenge in May.

Last week Brady had publicly urged the premier to drop her plans for a vote. In an interview Monday, he said, “Obviously there wasn’t sufficient support to press ahead successfully.”

May’s plan to delay the vote throws the Brexit process into further turmoil. She is due back in Brussels at a summit of EU on Thursday and is expected to ask for fresh concessions in an attempt to revive the chances of getting her deal through Parliament.

“Everyone knows what the bone of contention is — the backstop — and there are a large number of MPs who are prepared to compromise,” Brady said. Now the prime minister can go to Brussels and re-negotiate, he added.

May spent the weekend talking to fellow EU leaders to update them on her struggle and to explore possible changes to make the agreement more palatable. But the EU has said it won’t reopen negotiations.

The stakes for May are high. If Parliament refuses to ratify the withdrawal agreement, the U.K. will be on course to leave the EU without a deal, unleashing political and economic chaos. May herself could be forced from office and the U.K. might need a fresh election or a new referendum to resolve the crisis.

Delaying the vote is likely only to provide a temporary reprieve for the premier as she has promised to give Parliament a decisive say on whether to accept or reject the agreement before the U.K. leaves the bloc on March 29.

“Pulling the ‘deal’ vote would just delay the inevitable,” Tory MP Philip Lee tweeted. “Brussels will not grant any further significant concessions.”