The Prime Minister is feared to have given the EU the upper-hand in negotiations, as she made concessions to quell unrest from pro-Brussels Tory MPs.
In a major climbdown, she agreed to consider key aspects of a controversial amendment proposed by Tory Remainer Dominic Grieve.
Mr Grieve’s amendment, which would have secured a ‘meaningful vote’ on Mrs May’s Brexit deal, was voted down by 324 votes to 298, a majority of 26.
But to get the vote through, Mrs May agreed to a motion, which could be amended and will be put before MPs, in the event of a no-deal in November.
If the Commons decides to reject the Prime Minister’s divorce deal, Mrs May would be forced back to the negotiating table with the EU.
Brussels will now be able endlessly delay meaningful Brexit talks in the knowledge that Parliament would veto any hard Brexit.
This significantly strengthens the EU’s negotiating position as Mrs May does not have a strong enough majority, thus paving the way for a soft Brexit.
Brexiteers fear the Government has offered too many concessions to Remainers in order to secure a pyrrhic victory in the Commons.
The Prime Minister personally intervened by holding talks with would-be Tory rebels in her Westminster office before the Commons vote.
And Tory Chief Whip Julian Smith darted in and out of the chamber as he sought to persuade backbenchers to remain loyal.
Mr Grieve ended up voting with the Government – against his own amendment – and said he believes MPs will be offered a meaningful vote anyway.
He told Sky News: “I’ve voted with the Government following a meeting with that our concerns will be addressed.
“We had a personal assurance that we would find a way to address the concerns in the House of Lords when the Bill goes back there.
“I’m fairly confident we will be able to do that. There is goodwill to secure the protection we are seeking in the event of no deal.”
Two Tory MPs, Ken Clarke and Anna Soubry, voted against the Government.
But senior pro-EU Tory Sarah Wollaston, who had been expected to rebel, backed the Government.
Dr Wollaston tweeted: “Following further assurances that further Govt amendments will come forward in the Lords, I will now be supporting the Govt.
“For avoidance of any doubt, the promised further amendment in the Lords must closely reflect Dominic Grieve’s amendment.”
Stephen Hammond, another pro-Brussels Tory, said: “We have spoken in a room with the Prime Minister this afternoon, 10 minutes before the first round of voting.
“I absolutely trust what the Prime Minister says to us.”
Before the vote, Brexit Secretary David Davis warned warned Tory rebels that the Government was committed to honouring the 2016 referendum result.
He said: “A meaningful vote is not the ability to reverse the decision of the referendum.
“We will put in front of Parliament the decision for them to vote.
“After that there will be a process of primary legislation to put the actual details of it in Parliament, so Parliament will actually decide on the application of the detail.”
He added that the Cabinet would meet for two days at Chequers to finalise the Government’s Brexit White Paper and allow negotiations with the EU to speed up.
Meanwhile, Tory backbencher and ardent Brexiteer Sir Bill Cash branded Mr Grieve’s amendment “completely nonsense”.
He said: “There is no way the House of Commons, 650 members of Parliament, can arrive with a motion as to proscribe what the Government will do in relation to negotiations.
“It is not simply a question of whether or not we are departing from normal constitutional procedures. This amendment is complete nonsense.”
The Prime Minister’s judgement day over Brexit got off to abysmal start after the shock resignation of justice minister Phillip Lee.
In a dramatic statement, Dr Lee said Parliament was being sidelined and he could not support “how our country’s exit from the EU looks set to be delivered”.
He added: “If Brexit is worth doing, then it is certainly worth doing well; regardless of how long that takes. It is, however, irresponsible to proceed as we are.”
The Bracknell MP also called for Article 50 to be paused, extended or revoked to allow more time for negotiations.
However, he ended up abstaining on the vote this evening.
Labour’s shadow Brexit secretary Sir Keir Starmer said Mrs May said Mrs May’s “so-called concession” came as she faced a “humiliating defeat”.
He added: “We will wait and see the details of this concession and will hold ministers to account to ensure it lives up to the promises they have made to Parliament.”
Lib Dem Brexit spokesman Tom Brake added: “Time will tell as to whether this is just another attempt to buy off the rebels or a real attempt at consensus.
“But if we face the prospect of a ‘meaningless process’ rather than a ‘meaningful vote’, Parliament will be enraged.”
A Brexit Department spokesman said: “On the meaningful vote we have agreed to look for a compromise when this goes back to the Lords.
“The Brexit Secretary has set out three tests that any new amendment has to meet – not undermining the negotiations, not changing the constitutional role of Parliament and Government in negotiating international treaties and respecting the referendum result.
“We have not, and will not, agree to the House of Commons binding the Government’s hands in the negotiations.”
EU Withdrawal Bill breakdown of votes
Lords Amendment 110: Proposed to prevent the Government from using special powers to re-write EU regulations without parliamentary scrutiny. Tabled by Lord Lisvane, retired parliamentary official and crossbench peer.
Ayes: 324 Noes: 302 Majority: 22
Lords Amendment 128: Proposed strengthening parliamentary scrutiny of the use of secondary legislation. Tabled by Lord Lisvane.
Ayes: 325 Noes: 304 Majority: 21
Lords Amendment 37: Proposed removing the “11pm March 29 2018” exit date from the Bill and refers instead simply to “exit day”. Tabled by the Duke of Wellington, hereditary Tory peer.
Ayes: 326 Noes: 301 Majority: 25
Lords Amendment 39: Also proposed changing the definition of the exit day. Tabled by the Duke of Wellington.
Ayes: 324 Noes: 302 Majority: 22
Lords Amendment 125: Proposed requiring parliamentary approval of the UK’s exit date from the EU. Tabled by the Duke of Wellington.
Ayes: 328 Noes: 297 Majority: 31
Lords Amendment 19: Proposed that a withdrawal deal agreed between the Government and the EU must be approved by votes in the Commons and the Lords. Tabled by Viscount Hailsham
Ayes: 324 Noes: 298 Majority 26
Lords Amendment 52: Proposed removing the power from ministers to decide when retained EU law can be challenged in court.
Tabled by Lord Beith, Lib Dem peer.
Ayes: 326 Noes: 301 Majority: 25
Lords Amendment 10: Proposed restricting ministers’ use of powers dating back to the reign of Henry the Eighth to correct deficincies in retained EU law. Tabled by Lord Lisvane.
Ayes: 320 Noes: 305 Majority: 15
Lords Amendment 43: Further restrictions on ministerial use of so-called “delegated legislation” not requiring parliamentary scrutiny. Tabled by Lord Lisvane.
Ayes: 322 Noes: 306 Majority: 16
Lords Amendment 45: Proposed further restrictions on the use of ministerial powers. Tabled by Lord Lisvane.
Ayes: 317 Noes: 306 Majority: 11
Lords Amendment 20: Proposed making the use of powers to implement a withdrawal agreement dependent upon Parliamentary approval of a mandate for negotiations on the UK’s future relationship with the EU.
Tabled by Lord Monks, Labour peer and former general secretary of the Trades Union Congress.
Ayes: 321 Noes: 305 Majority: 16
A series of Lords amendments relating to the transfer of EU powers to the Scottish Parliament and other devolved assemblies.
Ayes: 321 Noes: 40 Majority: 281.
Additional reporting by Rebecca Perring and Macer Hall