MPs are to vote on the Government’s EU Withdrawal Agreement on Friday.
But the motion will not count as a third attempt to pass a “meaningful vote” on Theresa May’s deal, because it will not cover the future relationship with Europe.
Commons Speaker John Bercow cleared the motion for debate, ruling that it complies with parliamentary conventions which bar ministers from asking MPs to vote repeatedly on the same proposals.
But Labour and the DUP have said they will vote against the Withdrawal Agreement.
The Government’s move is set to allow Mrs May to present it as a choice between a short delay to Brexit and the potential for a much longer postponement which would mean taking part in European elections.
But it would not allow Parliament to go ahead and ratify the withdrawal deal, as Brexit legislation allows this only after the passage of a “meaningful vote” on both the Withdrawal Agreement and a Political Declaration on the future relationship.
Labour leader Jeremy Corbyn spoke to the PM by telephone for twenty minutes about the situation on Thursday, and said his MPs would not back the Government move.
A Labour spokesman said: “Jeremy made clear Labour will not agree a blindfold Brexit to force through Theresa May’s damaging deal, which would leave the next Tory party leader free to rip up essential rights and protections and undermine jobs and living standards.”
Significant doubts remain over whether Mrs May can secure a majority for the Withdrawal Agreement alone on Friday.
The agreement includes the controversial “backstop” customs arrangements for the Irish border which continues to represent the biggest obstacle to support from the DUP and Brexit-backing Tories in the European Research Group.
He told the BBC: “We will be voting against the Withdrawal Agreement because the concerns that we have about the trade border between Northern Ireland and the rest of the United Kingdom, and what that would mean in terms of who makes our laws – not Stormont or Westminster – those concerns remain.
“We regret the fact that we weren’t able to get to a position to support the Withdrawal Agreement, and the fact of the matter is that had there been legally binding changes at treaty level then we could have been in business.”
Moving the motion to enable the debate to take place on March 29 – initially slated as Brexit day – the Leader of the Commons Andrea Leadsom urged MPs to back the deal “so that we can leave the EU in an orderly way that gives businesses and people the certainty that they need”.
Downing Street has said that Mrs May will not move to a third meaningful vote – known in Westminster as MV3 – unless she believes she has a realistic chance of success, having seen it defeated by 230 votes in January and 149 in March.
This would buy time to seek wider agreement among MPs on the shape of the UK’s future relationship with the EU, in the hope of passing MV3 in April and leaving with a deal on May 22.
If the motion fails, the UK will have until April 12 to ask for a further extension to Brexit negotiations – which would require voters to choose new MEPs – or leave the EU without a deal.
Meanwhile, US President Donald Trump has praised Mrs May.
He told reporters outside the White House: “She’s a very nice lady. She’s a friend of mine.
“I hope she does well. I hope the Brexit movement and everything happening there goes very well.
“But, Theresa May is a very good woman. And, I’ll tell you what, she’s strong, she’s tough, and she’s in there fighting.”