The prime minister spoke to cabinet colleagues on Monday morning in a hastily arranged conference call, after apparently concluding she could not win over enough of the 100 Tory MPs who had said they were against the deal. The BBC's political editor Laura Kuenssberg quickly reported the same thing.
Sterling fell 1% on Monday after May opted to push back the debate on fears of an overwhelming defeat for her deal. Although May has so far ruled out taking the question back to the people of Britain, some of her more loyal ministers are already planning for just such a scenario, the Sunday Times said.
Critics said delaying the vote also highlighted her weakness.
Meanwhile, politicians within May's party have been pushing a new message to try and "sell" the deal.
"This vote is a lightning-rod realisation for some clients, that two years of ministerial resignations, chit-chat and speculation comes down to this: in three months we could be crashing out of Europe", said Matthew Hudson, CEO of MJ Hudson which advises more than 600 institutional and retail investment firms.
It is not just in London where traders will be gripped by the Brexit vote, with less than four months to go before Britain is due to leave the European Union on March 29.
"They also agreed that preparations for a "no deal" outcome should intensify", it said.
May is facing her biggest crisis since coming to power a month after the nation voted by a 52-48 margin in June 2016 to leave the world's largest single market after 46 years.
UK prime minister to delay Brexit vote, pound sinks
May's deal, which would see Britain keep close economic ties with the European Union, looks set to be rejected by Parliament on Tuesday.
May said that it was her duty to deliver Brexit, and that she would seek reassurances needed by parliament to complete the process.
May has warned that if MPs vote down her plan the country risks crashing out on this date with no agreement. This raises the prospect that the government could still face, and lose a vote on the deal even it it doesn't want to.
The rejection of the text in the House of Commons could lead to a Brexit without agreement on March 29.
Conservatives such as former foreign minister Boris Johnson, a leading Brexiteer, want May to renegotiate a unilateral exit from the backstop. We will not renegotiate the deal that is on the table right now. The 585-page document states that both sides will make "best endeavours" towards negotiating a trade deal to ensure there is no need for the backstop - an all-UK customs union that would act as a guarantee against a hard border on the island of Ireland.
Brexit looks as if it will make headlines from the start, with the European Court of Justice due to rule on Monday morning whether the United Kingdom can unilaterally revoke Article 50.
Calls for a new referendum now attract significant cross-party support from dozens of MPs.
"We have a common determination to do everything to be not in a situation one day to use that backstop, but we have to prepare", he said.
France tells Trump to stop interfering in its politics
He was referring to violent protests in France which saw fires in the capital, and police using tear gas and water cannons. The number of people arrested during Saturday's protest movement "yellow jackets" in France has reached 1726.
Dolphins Beat Pats on Desperate Lateral Play
The Chiefs defence forced a turnover but Harrison Butker missed from 43 yards with a potential game-winning field goal. Brady's young daughter offered an explanation. "Football", said Patriots quarterback Tom Brady , "is a insane game".
Australia v India: first Test, day four
But that was when David Warner was using his Kaboom and Steve Smith was playing shots most could only dream of. Ajit Agarkar, who was part of the Indian team which won a Test at Adelaide during India's 2003-04 tour.
USA And Universal Health Care
This is because the each state has its own different set-up on all levels socially, financially and geographically. Each state has populations equivalent to nations with universal coverage hence size can never be a limiting issue.