Jeremy Corbyn has swung the Labour leadership behind a second EU referendum with an option to remain should his party’s preferred plan not get through Parliament.

The dramatic move came as Theresa May’s plane touched down following her trip to Egypt when she insisted a deal with Brussels was “within our grasp”.

But she placed herself on a collision course with a large number of Tory colleagues, including some in the Cabinet, when she set her face against calls to put back exit day from March 29 to allow more time for talks.

Today, she will update MPs on the “progress” in the Brussels talks; key will be the wording of the Government motion to be debated and voted on tomorrow evening.

After days of senior figures saying Labour was “moving towards” supporting a People’s Vote, Mr Corbyn announced the shift during a two-hour meeting of the Parliamentary Labour Party at Westminster.

He explained Labour would table its own amendment, calling for a customs union with a UK say and close alignment with the single market, and would also support his colleague Yvette Cooper’s amendment to extend the Article 50 process to avoid a no-deal outcome.

But, significantly, the party leader said, if those failed, Labour would back an amendment “in favour of a public vote to prevent a damaging Tory Brexit".

A senior party source said the “assumption” would be that Remain would be on the ballot paper but made clear it would not be a straight choice between the Government’s deal and Remain as the former was unacceptable; various options were being considered.

But not everyone was happy. Backbencher John Mann reportedly claimed people in the North of England would "never vote Labour again". He told Mr Corbyn: “This decision will stop you being Prime Minister.”