JEREMY Corbyn will come under intense pressure today from senior colleagues and grassroots members to swing Labour fully behind the campaign to keep Britain in the EU - but he is determined to resist it.

Senior sources close to the party leader were confident the leadership would win the key vote following what is set to be an impassioned debate at Labour’s autumn conference in Brighton.

The party’s ruling National Executive Committee voted to back Mr Corbyn’s approach; to go into an election, offering a referendum with the choice of a Leave option – a Labour Government’s new withdrawal agreement with Brussels – and a Remain option.

One senior insider told The Herald: “It’s a vote, so anything can happen, but there is a lot of support for Jeremy’s approach.”

At the conference fringes a string of senior figures insisted the party had to be clear and come out unequivocally before a general election for Remain or face losing a lot of votes.

Sadiq Khan, the London Mayor, said: “We are at a vital crossroads, neutrality is not an option. The party should be unequivocally pro-Remain."

Richard Leonard, the Scottish Labour leader, called on the UK leadership to give “clarity” on its position; his is to back Remain.

Emily Thornberry, the Shadow Foreign Secretary, was also ebullient, saying: “We must demand that the public has a final say and we must not just campaign to Remain but we must lead the campaign to Remain."

However, Len McCluskey, the leader of the Unite union, who is said to have Mr Corbyn’s ear, sent out a stark warning to the likes of Ms Thornberry, urging them to “support your leader” and, if they could not, then they should “step aside from the Shadow Cabinet…and they can argue for whatever they want”.

Meanwhile, the UK Supreme Court’s eagerly-awaited ruling on whether Boris Johnson’s decision to suspend the UK Parliament for five weeks was lawful is expected in the next 48 hours or so. Mr Corbyn said that if the 11 justices found against the Prime Minister, then the Commons must be recalled immediately.