It comes amid reports last night that Brussels was considering granting a Brexit extension until February. Sir Keir confirmed Labour will also try to change the deal to include the UK being in a customs union with the European Union after Brexit in a move that would potentially torpedo the whole agreement. The Brexit-wrecking plan was met with outrage from Tory MPs last night. Tory Brexiteer Nigel Evans said: “They have finally been smoked out as the wrecking Remainers they are.
“No to no deal, no to a deal, no to an early election – and reneging on their election manifesto of just two years ago.
“It’s been delay after delay after delay, and the next stage is to wreck the deal.
“People know that a customs union and single market is simply not Brexit.
“A second referendum is nothing more than a short term self-protection device where their own jobs are not at risk.”
Conservative MP Philip Davies said: “Labour’s amendments are all about overturning the referendum result, but they haven’t got the guts to tell their northern working class voters.
Brexit blockers: McDonnell and Starmer
“However, those voters are not as stupid as Labour’s London-centric leadership think they are. When Labour finally have the guts for a general election, they will find that out.”
Tory Michael Fabricant said: “Labour are languishing in the polls, far behind the Tories.
“Their so-called game plan is to delay or stop Brexit so that Boris is discredited and then they will finally allow a general election to be called. Wrong! I think the public will see through this, know that Labour are the Brexit wreckers, and they will be deservedly punished when the time comes.
The MP added: “The silent majority want a real Brexit on October 31 and will not forgive those MPs who seek to hinder it.”
Mr Johnson is expected to try to pass his deal into law with a vote on the Withdrawal Agreement Bill tomorrow, which would allow Britain to leave the European Union on October 31.
But Remain-backing MPs will use the opportunity to try to change the PM’s deal and delay the whole process.
Sir Keir told the BBC’s Andrew Marr Show it was “inevitable” the second referendum amendment would be tabled.
He said: “It’s been down many times when we’ve got to this stage of the exercise. When that Bill goes down it is inevitable that that amendment will be put down, because a growing number of people now think the only way truly to settle this is to ask people, ‘do you want to leave on these terms or would you rather remain?’’
Asked if Labour would back such an amendment, Sir Keir replied: “Yes. Almost every victory we’ve had on anything in the last three years has come from the backbenches. That’s how we got the meaningful vote, that’s how we got any progress in this.”
Mr McDonnell agreed with Sir Keir that the amendment would have the best chance of success if it was tabled by a backbencher rather than Jeremy Corbyn.
He told Sky News: “Sometimes the tactical choice on this is that sometimes it is better coming from a group of MPs from the backbenches where you can get cross-party agreement, and we have spoken about this on your programme some months ago now I think inevitably that will come up but we’ve always said on a deal like this, if Boris Johnson is confident about this deal, go back to the people with it.”
Labour has already whipped its MPs multiple times to back a second vote, but no attempts have succeeded so far.
But it is unclear what Jeremy Corbyn himself thinks of the plan.
Last week he said he would “caution” MPs against backing the PM’s Brexit deal, even if there were a referendum attached.
Labour has long advocated a softer Brexit plan which would see the UK stay closer aligned to the bloc and stay in a customs union with Brussels.
Meanwhile, Sir Keir confirmed Labour will try to force through a major change to Mr Johnson’s proposed divorce agreement by inserting a requirement for the UK to be in a post-Brexit customs union with the EU.
He said: “We’ve been arguing for a very long time now for a customs union with the EU and for single market alignment.
Boris Johnson could be stymied by Labour shenanigans
“There are other amendments that are really important because there is a trap door to no deal at the end of 2020 that we need to deal with and close, and we can do that in the legislation.
“And of course we need an amendment to say that whatever deal gets through it should be subject to a referendum where that deal is put to the public and they’re asked, ‘do you want to leave on these terms of would you rather remain in the EU?’ So next week’s going to be busy.”
Mr Johnson’s current Brexit deal would see the UK leave the EU customs union, allowing Britain to strike its own trade agreements in the future.