John McDonnell has said he will “have a word” with Labour MPs to stop them voting in favour of Boris Johnson’s Brexit deal this weekend.
The prime minister is heading towards a dramatic Commons showdown on Saturday after he secured an exit deal with the EU.
Johnson’s chances of winning the vote are on a knife-edge after the DUP confirmed its 10 MPs would vote against him.
To win, No.10 will have to rely on Labour backbenchers defying Jeremy Corbyn’s orders and voting with the government.
HuffPost UK understands the party whip will not be withdrawn from Labour MPs who vote for the deal. But there will likely be other consequences for them once the immediate Brexit process is over.
Speaking to BBC Radio 4′s Today programme on Friday morning, McDonnell warned Labour MPs that no one who had “the true interest of their constituents at heart” could back the deal.
The shadow chancellor said Johnson’s Brexit deal was worse than Theresa May’s as it would give the Conservatives the opportunity of “undermining workings rights and impoverishing working people”.
On Thursday night, veteran left-wing Labour MP Ronnie Campbell told BBC Newsnight he was minded to vote for Johnson’s deal as voters were “fed up”.
McDonnell told Today: “I’m going to have a chat with Ronnie, because he is a good socialist and all his life he has fought alongside me to protect trade union rights and develop trade union rights.
“Boris Johnson and those Tory MPs that populate the cabinet, these are the extreme right who have attacked trade unions throughout their political careers.”
He added: “No MP, as far as I’m concerned, who has the true interest of their constituents at heart can allow that to happen.”
A total of 635 votes will be in play when the deal is debated, which means the government will need at least 318 votes to be certain of a majority. If every Conservative MP who is able to vote also backs the deal, this gives the government 285 votes.
A handful of other Labour MPs have also indicated they would be prepared to vote for the deal. Graham Stringer, who campaigned for Leave, told LBC Friday morning he was “thinking hard” about backing the PM.
“This is a bigger issue than party loyalty. I want to vote with my party. That’s my first thought, but in the interests of the country getting this sorted out is vital, and so I will make my decision on Saturday morning,” he said.