Extra day of parliament seen as moment to test support for move as Corbyn urged to back it

Pro-remain MPs are planning a crunch vote on a second referendum during the “super Saturday” sitting of parliament, as Jeremy Corbyn comes under intense pressure from senior allies to back another Brexit vote before an election.

Several MPs involved in the People’s Vote campaign said the special parliamentary session on 19 October could be the key moment when the House of Commons will test whether there is support for a second referendum.

Speaking in Northampton, Corbyn brushed off a suggestion that Labour should be pushing for a second referendum before an election. Asked whether another referendum should come first, he said: “A second referendum is what we propose under a Labour government, which would be, as I have said, not a choice between a no-deal cliff edge but between an intelligent arrangement with the European Union and remain.”

There are several stages yet to conclude before the circumstances of the Saturday sitting become clear, chiefly whether Boris Johnson manages to get a deal from the EU summit on 17 and 18 October. Pro-remain MPs could try to attach a confirmatory referendum on to any deal he secures. If no deal is agreed, the rebels have the option of trying to table Theresa May’s withdrawal agreement bill from the backbenches with a second referendum promised on the face of the legislation.

One source with knowledge of cross-party talks said there were “four or five plans floating around” but there was a possible alliance for a confirmatory vote emerging between supporters of a second referendum, pro-deal Labour MPs and Tories or former Tories nervous about the prime minister winning an election on a no-deal Brexit platform.

Peter Kyle, one of the Labour MPs behind the Kyle-Wilson amendment seeking a confirmatory referendum on a deal, said: “We are very clearly in the end game. We are prepared for any eventuality – a motion, an amendment or a more novel move. Saturday 19 will be a key moment because it is after the EU summit. In the absence of Boris Johnson being capable of delivering the deal he promised, it’s blindingly obvious that the next best option is the one that already exists or a similar version of it.

“Parliament might well want to re-examine that. If Boris Johnson comes back empty-handed, then parliament will be forced to be the grown-up in the room and find a workable proposition.”

He said it would be “irresponsible” for Labour to agree to an election before a second referendum on a deal has resolved the Brexit issue.

Hilary Benn, the Labour MP and chair of the Brexit committee, also said the 19 October sitting would provide an opportunity for those pushing for a second referendum.

He told the BBC’s Newsnight programme: “If parliament is going to be meeting we have shown our capacity as parliamentarians to take control of the order paper, so we won’t be meeting just to sit and see what the prime minister has in store for us, this is an opportunity – if we can get a majority, and that is a big if – for parliament to say we can find a way forward, a confirmatory referendum is the way to do it, let’s go and ask the British people finally to take the decision.”

Labour would be crucial in this plan, with Corbyn already coming under huge pressure from senior shadow cabinet ministers to back a second referendum before agreeing to an election, especially when the party is not performing well in the polls.

Emily Thornberry, the shadow foreign secretary, went public with her concerns in an interview on the BBC’s Victoria Derbyshire show on Thursday.

“My concern about if we had a general election, is it would be a kind of quasi-referendum, that it would be all about in or out, what kind of deal, and so to a certain extent I can see the sense in trying to have a referendum first. But it’s really just a question of how can we do that in practice,” she said.

Corbyn had flatly rejected the idea when it was proposed last month by his deputy, Tom Watson. But since then, members of his shadow cabinet have raised concerns that an early election could be a “trap” that lets Johnson dominate on the issue of Brexit.

The shadow cabinet is due to tackle the timing of a general election again next week, after an inconclusive discussion this week.

Corbyn himself appeared “gung ho” about an election, according to one close ally. But several other shadow ministers, including Keir Starmer and John McDonnell, have struck a more cautious note.

There was also a “strong hint” that those who favour a referendum before a general election plan to press for it in parliament, according to one person present at the meeting.

Labour insiders say the push for a second referendum before an election has been made easier by the moving of Karie Murphy, Corbyn’s chief of staff, out of the leader’s office and into an election role at party HQ. She was among those who were keen to see an early general election, as well as being sceptical about the party adopting a remain stance. One described it as a “game-changer” for those trying to shift Corbyn towards a more unequivocally pro-remain position.