Boris Johnson has said he will give MPs more time to debate his Brexit deal, but only if they agree to a 12 December general election.
The prime minister told the BBC he expected the EU to grant an extension to his 31 October deadline, even though he “really” did not want one.
He urged Labour to back an election in a vote he plans to hold next week.
EU leaders are expected to give their verdict on delaying Brexit for up to three months, on Friday.
Commons leader Jacob Rees-Mogg told MPs the government would on Monday table a motion calling for a general election.
Shadow leader of the House Valerie Vaz said Labour would back an election “once no-deal is ruled out and if the extension allows”.
Labour would offer the PM its support for a “proper timetable” for the Brexit bill to allow MPs to scrutinise and amend it, she added.
In a letter to Labour leader Jeremy Corbyn, Mr Johnson says his “preferred option” is a short Brexit postponement “say to 15 or 30 November”.
In that case, he writes, he will try to get his deal through Parliament again, with Labour’s support.
The prime minister adds that he “assumes” Mr Corbyn “will cooperate with me to get our new Brexit deal ratified, so we leave with a new deal rather than no deal”.
If, as widely expected, the EU’s Brexit delay is to the end of January, Mr Johnson says he will hold a Commons vote next week on a 12 December election.
If Labour agrees to this, the government says it will try to get its deal through before Parliament is dissolved for the campaign on 6 November.
The prime minister told the BBC’s Laura Kuenssberg: “I’m afraid it looks as though our EU friends are going to respond to Parliament’s request by having an extension, which I really don’t want at all.
“So, the way to get this done, the way to get Brexit done, is, I think, to be reasonable with Parliament and say if they genuinely want more time to study this excellent deal, they can have it but they have to agree to a general election on 12 December.”
Asked what he would do if Labour refused to vote for an election, he said: “We would campaign day after day for the people of this country to be released from subjection to a Parliament that has outlived its usefulness.”
The prime minister has repeatedly insisted the UK will leave the EU on 31 October, with or without a deal.
But he was forced to send a letter to the EU requesting an extension, under legislation passed by MPs last month.
MPs voted on Tuesday to back the first stage of the Withdrawal Agreement Bill, putting the deal the PM agreed with Brussels into law – but rejected Mr Johnson’s plan to push it through the Commons in three days.
The BBC’s Europe editor Katya Adler says EU leaders are set to decide on Friday whether to grant the UK a three-month Brexit extension.
Most EU nations back it but France “is digging its heels in”, she adds.
So there could be an emergency summit in Brussels on Monday to allow leaders to reach agreement face-to-face.
President Macron favours a short, sharp Brexit delay, encouraging MPs and the UK government to concentrate on ratifying the newly negotiated Brexit deal.
Mr Macron is fed up with the more-than-three-year EU focus on Brexit and the ever-present threat of a no-deal scenario.
He would rather shift attention to reforming the EU itself, to the benefit (he believes) of the countries remaining in it.
