On a day of high political drama, rebel ringleader Dominic Grieve pulled support for his own amendment to the EU (Withdrawal) Bill which aimed to give parliament a “meaningful vote” over the process.
It would have ensured the Commons had the opportunity to block a “no deal” Brexit in the event Mrs May was unable to reach a deal with Brussels.
The bill must now go back to the House of Lords in the latest instalment of “parliamentary ping-pong”.
But Wednesday’s Commons vote essentially means the PM has won the battle over her flagship Brexit bill.
In a dramatic afternoon at Westminster, Mr Grieve told fellow MPs that he was backing down after receiving “obvious acknowledgement of the sovereignty of this place over the executive” in the form of an official ministerial statement which emerged minutes before the debate began.
There were cries of “shame” as the former attorney general explained why he was changing course.
But while Mr Grieve withdrew support for his amendment, he still moved it to allow MPs to have their say.
In the ensuing vote, the government prevailed by 319 votes to 303, a majority of 16.
Six Conservative MPs rebelled against the government and backed the Grieve amendment – Heidi Allen, Ken Clarke, Antoinette Sandbach, Sarah Wollaston, Phillip Lee and Anna Soubry.
Four Labour MPs sided with the government – Frank Field, Kate Hoey, John Mann and Graham Stringer.
Labour’s shadow Brexit secretary Sir Keir Starmer described the result as “disappointing”, accusing the PM of “buying off her own MPs at the eleventh hour”.
The Lib Dems said the “so-called Tory rebels” had “lost their bottle and caved into yet another pathetic government compromise that isn’t worth the paper it is written on”, while SNP leader Nicola Sturgeon said the concession was a “fudge”.
Meanwhile, arch Brexiteer Jacob Rees-Mogg said the day’s events were a “happy occasion when all may claim an element of success”.
Mr Grieve had tabled an amendment to the EU (Withdrawal) Bill which would have required MPs to be given the chance to approve or reject the government’s next steps on Brexit in the event that no agreement was reached by Brexit Day in March 2019.
The government instead offered only an unamendable “neutral motion”, which would have allowed MPs to take note of the situation.
In a sign of how determined Downing Street was to win the day, Tory whips made clear they would not observe the parliamentary convention allowing votes to be “nodded through” from ambulances and cars in the courtyard outside if MPs are too physically ill to vote in the normal way.
Naz Shah, Labour MP for Bradford West, was pushed in to vote in a wheelchair with a sick bucket on her lap, while pregnant Lib Dem deputy leader Jo Swinson turned up to vote despite being past her due date.
The ministerial statement from Brexit secretary David Davis explicitly says the parliamentary rule-book allows the Speaker to determine whether a motion is amendable or not.
It also notes there is a parliamentary convention that time is made available to debate motions tabled by MPs on important issues.
But Number 10 said ministers were confident of formulating a motion which John Bercow will rule is unamendable.
The PM’s official spokesman told reporters: “We will ensure that under standing orders the motion we bring forward is neutral.”