Labour conference will vote on a motion that if passed will mean it must back “a public vote” on Brexit if Jeremy Corbyn cannot secure a general election.

The compromise motion that will be voted on this Tuesday was hammered out after a sometimes heated meeting that lasted almost six hours at the conference in Liverpool.

The critical section will say that if Theresa May’s Brexit plans collapse but the Tories refuse to call an election, “Labour must support all options remaining on the table including a public vote”.

The Independent has launched its Final Say campaign for a People’s Vote on whatever the outcome of Brexit is, with more than 820,000 people having signed its petition so far.

One Labour delegate inside the room when the motion was agreed, said: “There were endless speeches from all sides of the debate, a lot of push and pull. But the majority who wanted the support for a referendum strengthened won out.”

An early draft of the motion put forward by the Labour leadership was six pages long and only mentioned a new public vote on Brexit as an option to be considered, but a more tightly worded version was proposed by the Remain-supporting TSSA union boss Manuel Cortes.

The motion that was finally agreed reads: “If we cannot get a general election Labour must support all options remaining on the table including campaigning for a public vote.

“If the government is confident in negotiating a deal that working people, our economy and communities will benefit from they should not be afraid to put that deal to the public.”

Frontbench sources emphasised that the key line in the motion committed Labour to supporting a campaign for a new referendum in addition to other options, if the prime minister blocks any drive for a new general election.

We are now talking with clarity of voting down deal if doesn’t meet our tests, calling for a general election and if that is not possible – we want a public vote on the deal

Pro-EU Labour figure

Story continues

The meeting had begun at around 6pm on Sunday with more than one hundred delegates cramming into a room in the depths of the conference centre in Liverpool.

It was not until almost midnight that reports that a deal had been reached inside emerged, with eventual outcome getting a mixed reaction.

One pro-EU Labour figure said: “This is clear movement from the party. We are now talking with clarity of voting down a deal if doesn’t meet our tests, calling for a general election and if that is not possible – we want a public vote on the deal.

“Last year we didn’t even get a debate. What a difference a year makes.”

But others pointed out that there were still gaps in the wording, for example that it failed to set out what the other “options” would be and if they would take priority, not to mention the fact that the motion does not spell out what a new referendum would ask.

They pointed to comments made by Unite general secretary Len McCluskey, one of Mr Corbyn’s closest allies and leader of a union that is Labour’s biggest financial backer.

He said earlier in the day: “The referendum shouldn’t be on, ‘Do you want to go back in the European Union’.

“The people have already decided on that. We very rarely have referendums in this country, the people have decided against my wishes and my union’s wishes, but they have decided.”

A YouGov poll commissioned by the People’s Vote campaign showed nearly 90 per cent of Labour Party members want another referendum, three-quarters would like to see a commitment in Labour’s manifesto – but critically, it shows that 93 per cent would vote to stay in the EU if they were given a chance.

But Mr McCluskey went on: “There are significant numbers of traditional Labour supporters who are saying, ‘We’re going to vote Conservative because we don’t trust Labour to take us out of the European Union’, despite the fact that Jeremy has said repeatedly, ‘Of course, we recognise the result, of course we respect the result, we are coming out of the European union’.

“For us now to enter into some kind of campaign that opens up that issue again, I think would be wrong.”