Labour leader Jeremy Corbyn is eyeing plans to ambush Boris Johnson by trying to force a House of Commons vote on a second EU referendum should the prime minister bring a new Brexit deal before parliament.
Senior Labour figures said it was “conceivable” that the party would pursue attaching a confirmatory referendum to any new withdrawal agreement while also pushing for a general election.
Mr Johnson’s hopes of getting his new Brexit plan through parliament rose on Friday after Northern Ireland’s Democratic Unionist Party chose not to immediately reject his proposal to try to resolve the vexed question of the Irish border after Brexit.
The DUP is highly influential with Eurosceptic Conservatives, and these two groups of MPs combined to oppose Theresa May’s Brexit deal — she failed on three occasions to secure parliamentary approval for her withdrawal agreement reached with the EU.
But Mr Johnson could face a political landmine should Labour seek to muster cross-party support for a confirmatory referendum being tied to any Brexit deal finalised by Mr Johnson with the EU.
Mr Corbyn said on Thursday he wanted an election as soon as possible to topple Mr Johnson’s government and replace it with a socialist administration.
But some shadow cabinet members favour pushing for a second EU referendum — without making a commitment to backing any Brexit deal forged by Mr Johnson.
Labour could seek to attach a referendum to a revised withdrawal agreement through a Commons amendment.
One Labour figure said that if Mr Johnson managed to strike a deal with the EU, Britain would be heading for either a referendum or an election, with Labour far behind in the opinion polls. “The question will be, what’s the least worst option [for the party],” he added.
Meanwhile DUP leader Arlene Foster did not directly rule out supporting Mr Johnson’s latest Brexit proposal, saying instead she was in regular in touch with the prime minister who was “aware of our views”.
She added the party would use its “considerable influence” to stand up for Northern Ireland’s “long-term economic and constitutional interests” over the next few days of negotiations between the UK and the EU.
“Anything that traps Northern Ireland in the European Union, whether single market or customs union, as the rest of the United Kingdom leaves will not have our support — the prime minister is very mindful of that.”
Eurosceptic Conservative MPs welcomed Mr Johnson’s apparent progress towards striking a new Brexit deal and the news that talks were entering a more detailed phase that could produce a reworked treaty.
“It’s a good thing we’ve entered a more intense phase of talks but we’ll give an opinion when we see what they’re discussing,” said Mark Francois, deputy chair of the pro-Brexit European Research Group of Tory MPs.
While the ERG lambasted Mrs May’s Brexit deal, the group is likely to follow the lead of the DUP on whether Mr Johnson’s Northern Ireland proposal is acceptable.
Other leading Eurosceptic Conservatives warned that any Brexit deal must still pass their test of being “a Brexit worth having”, adding they would “absolutely not” support any agreement that involved delaying the UK’s departure beyond October 31.
Mr Johnson has appointed three senior Eurosceptics to prominent ministerial positions: home secretary Priti Patel, environment secretary Theresa Villiers and Brexit minister James Duddridge. They are expected to back his latest Brexit proposal.