Jeremy Corbyn will repeat his demand for Theresa May to call a general election in order to “break the deadlock” over her Brexit deal.
The Labour leader will use a speech on Thursday to reissue the challenge to the prime minister ahead of MPs’ crunch vote on Mrs May’s EU agreement next week.
The prime minister dramatically pulled a pre-Christmas vote on her Brexit deal amid the expectation of a heavy defeat.
There has yet to be signs of a significant shift in attitudes among sceptical MPs, despite government efforts to win over opponents of the agreement.
Speaking in Wakefield, Mr Corbyn is expected to say: “Let there be no doubt: Theresa May’s deal is a bad deal and Labour will vote against it next week in parliament.
“If the government cannot pass its most important legislation, then there must be a general election at the earliest opportunity.
“A government that cannot get its business through the House of Commons is no government at all.
© PA Shinzo Abe and Theresa May will hold talks in Downing Street
“So I say to Theresa May: if you are so confident in your deal, call that election, and let the people decide.”
Mr Corbyn is under increasing pressure from many of his MPs and Labour supporters to give his backing to a second EU referendum.
But the Labour leader will describe an election as “not only the most practical option, it is also the most democratic option”.
Suggesting an incoming Labour government would strike their own Brexit deal with Brussels, Mr Corbyn will add: “It would give the winning party a renewed mandate to negotiate a better deal for Britain and secure support for it in parliament and across the country.”
The Labour leader’s speech will be scrutinised for signs Mr Corbyn could back a delay to Brexit amid the current impasse in parliament on Mrs May’s deal.
On Wednesday, as MPs resumed their debate on the prime minister’s agreement, Labour shadow Brexit secretary Sir Keir Starmer told the House of Commons an extension to the Article 50 period “may well be inevitable now”.
Responding to Mr Corbyn’s expected comments, Labour MP Jo Stevens warned her leader of an “historic” election defeat if the party adopted a pro-Brexit position before a national poll.
The Cardiff Central MP, a supporter of the People’s Vote campaign for a second EU referendum, said: “The EU has made it clear, repeatedly, that there is no prospect of a deal that differs, in any substantial form, from that negotiated with Theresa May.
“If we go into a general election on a pro-Brexit Labour platform the result could be an electoral reverse that would rival the historic defeats of 1931 and 1983 in scale and depth.”
Meanwhile on Thursday, Mrs May will hold talks with Japan’s prime minister Shinzo Abe in Downing Street, where the two leaders will renew their commitment to a post-Brexit trade deal.
The visit has prompted speculation Mr Abe has been flown in to bolster international support for the prime minister’s Brexit agreement.
However, there was little sign Mrs May’s charm offensive with Tory MPs had yet to secure further backing for her deal, as the prime minister hosted a second drinks reception in Number 10 on Wednesday night.
Top Brexiteer Jacob Rees-Mogg, the chair of the European Research Group of Conservative eurosceptics, said on his departure from Downing Street: “I doubt it will change many votes on the withdrawal agreement.
“I don’t think that was really the effort. I think it was a useful reminder that the Conservative Party is much more united on other things than it may be on Europe.”
MPs will continue their debate on Mrs May’s agreement on Thursday, prior to Tuesday’s scheduled vote.