Theresa May’s government faces a vote of no confidence later after MPs rejected the PM’s Brexit deal.
Labour launched the bid to trigger a general election after the deal setting out the terms of Britain’s exit from the EU was rejected by 230 votes.
However, one senior party figure has suggested it is unlikely to succeed, with Northern Ireland’s DUP and Tory rebels saying they will back the PM.
The confidence vote is expected to be held at about 1900 GMT.
Mrs May has told MPs she will return to the Commons with an alternative plan next week, provided she survives the confidence vote.
“The House has spoken and this government will listen,” she said on Tuesday, offering cross-party talks to determine a way forward.
MPs are set to debate the motion for about six hours following Prime Minister’s Questions at 1200, with Labour leader Jeremy Corbyn saying it would allow them to give their verdict on “the sheer incompetence of this government”.
BBC political correspondent Iain Watson says that if the prime minister sees off the challenge, she will begin a series meetings with “senior Parliamentarians” on Thursday.
He said Mrs May intended to retain her “red lines” – ruling out Labour’s demand for a customs union with the EU – with sources suggesting compromising on this would risk cabinet resignations.
But first she must survive the confidence vote tabled by Mr Corbyn and backed by MPs from the SNP, Lib Dems, Plaid Cymru and Green Party.
Shadow international trade secretary Barry Gardiner suggested Labour might have to force a series of confidence votes if it is to unseat the PM.
“The numbers are probably not there tomorrow,” he told the BBC. “We will hope that we can. But it is not about a one-off thing.”
