How many votes does Theresa May need to get her deal over the line?

Prime Minister Theresa May needs at least 318 votes for a majority in Tuesday’s Brexit vote Credit: House of Commons/PA

Theresa May has urged MPs to “come together, to back this improved Brexit deal”, maintaining she has secured legal changes to the controversial backstop.

But has she done enough to she reverse the humiliating 230-vote defeat she suffered the last time the Commons passed judgment on her Brexit plan?

There are 634 votes in play, which were split 202 in favour and 432 against on the last vote.

Mrs May needs at least another 116 votes on Tuesday night in order to reach the necessary 318 votes to give her a much sought-after majority.

If for example she gained the support of 10 DUP MPs, 70 more Tories and 36 more Labour members, she could claim victory.

But the DUP MPs, whose support the Prime Minister relies on in the Commons, have not yet indicated whether Mrs May’s latest efforts are enough to convince them to support it.

They have said the deal needs “careful analysis”, and added that they will scrutinise the text “line by line” before forming a judgment.

Credit: PA Graphics

In what could be interpreted as a potentially positive sign, Jacob Rees-Mogg, chairman of the The European Research Group, described the deal as “clearly a step in the right direction”.

He said whether or not the DUP ends up supporting the deal will be “a very important and significant factor”.

Perhaps unsurprisingly, Labour leader Jeremy Corbyn has urged MPs to reject the deal, and Shadow Brexit secretary Sir Keir Starmer said he will be surprised if the changes that have been made are sufficient to allow the Attorney General to alter his most recent legal advice.

Prominent Tory backbencher Damian Collins, who backed remaining in the EU in 2016, said he will be voting against the Government’s motion, while former Brexit minister and ERG member Steve Baker said he thinks the deal “falls very far short of what the Government whipped us to vote for”.

Prominent Remain figure Nicky Morgan signalled support for the changes, while Tory pro-European Dominic Grieve said he would vote against the deal.

The Independent Group – the recently-formed contingent of 11 former Labour and Tory MPs – has tabled an amendment to the motion to be debated, calling for an extension to Article 50 so Parliament can agree the terms of a so-called People’s Vote.

The current state of the parties is:

  • Conservative: 314

  • Labour: 245

  • SNP: 35

  • Lib Dems: 11

  • The Independent Group: 11

  • DUP: 10

  • Plaid Cymru: 4

  • Green: 1

  • Independents: 10