Mrs May suffered a crushing defeat in the Commons today after MPs voted in favour of amendment seven which means they will have to vote the final Brexit deal into effect.
This gives them the ability to force the Prime Minister to go back to Brussels and strike another deal.
Chair of the National Infrastructure Commission and former Transport Secretary and Schools Minister, Lord Andrew Adonis, said: “First step towards defeat of Brexit. And this is before the Lords has got going on the National Betrayal Bill.”
One Twitter user responded to Lord Adonis: “Balls to democracy eh? There was a democratic vote in favour of Brexit. It appears, however, to have taken a knock tonight.”
Former chief of staff to Theresa May, Nick Timothy replied: “Dream on, Lord A.”
But, responding to Nick Timothy, Conservative MP for Broxtowe and arch-Remainer, Anna Soubry, said: “Oh dear, yet more nonsense from the man who helped lose the Conservatives a majority in the General Election.”
One Tory Brexiteer vented their outrage at the vote and called for the rebels to be deselected.
Conservative MP for Mid Bedfordshire Nadine Dorries said: “Tonight, the Tory rebels have put a spring in Labours step, given them a taste of winning, guaranteed the party a weekend of bad press, undermined the PM and devalued her impact in Brussels.
“They should be deselected and never allowed to stand as a Tory MP, ever again.”
She added: “I’ve been a rebel myself, but never when a Marxist government was knocking at the door.”
The general public also launched a scathing attack.
One Twitter user replied to Anna Soubry saying: “Pot, kettle! This from the so-called Conservative MP that should be sat on the opposite side of the house!
“You’ve let your party down this evening and those who for voted for you to sit in the back row.”
Another said to Ms Soubry: “You voted with the hard left and the Nationalists; no way back for you.
“When the Political class vote down Brexit, you watch the rise of the right and remember this post; you contributed.”
The amendment passed with 309 in favour and 305 in opposition.
Along with Mr Grieve, MPs Ken Clarke, Nicky Morgan, Anna Soubry, Antoinette Sandbach, Stephen Hammond, Sarah Wollaston, Jeremy Lefroy, Robert Neill and Heidi Allen all signed off on the amendment ahead of the vote.
But in total there are believed to have been 11 Tory rebels who backed the amendment.
In a mocking statement, Jeremy Corbyn described the vote as a humiliation for the Prime Minister.
He said: “This defeat is a humiliating loss of authority for the government on the eve of the European Council meeting.
“Her refusal to listen means she will now have to accept Parliament taking back control.”