Labour has thrown its weight behind an early general election, significantly boosting the chances of voters going to the polls before Christmas.
Leader Jeremy Corbyn dropped his opposition to a snap election after the EU granted a Brexit delay until 31 January 2020 to avoid a no-deal divorce.
MPs will vote this evening on the proposal for a snap poll, which would be the first December general election for almost a century.
But there is disagreement between the political parties over what date it should be held.
Boris Johnson has pushed for Thursday 12 December.
But Labour and the Lib Dems prefer 9 December in order to dissolve parliament earlier and remove any chance of the prime minister’s Brexit bill being fast-tracked through parliament.
Mr Corbyn has also expressed concerns about whether students will have already finished their term and gone home by 12 December, which he claims could hinder their ability to vote.
“We are going out there to fight an election campaign and I can’t wait to get out there on the streets,” he said after a meeting of Labour’s shadow cabinet.
But several Labour MPs have already declared they will defy orders and vote against a snap election.
One, Barry Sheerman, called the decision “sheer madness” and said he had heard frontbenchers and whips were “resigning” over the issue.
Education Secretary Gavin Williamson said a new set of MPs was needed to replace the “rotten” and “broken” current parliament that is “standing in the way of the British people”.
“It is welcome to see that Labour are moving in a general election, but let them vote for a general election, not just talk about it,” he added.
MPs have three times rejected Mr Johnson’s bid for a snap election, which he needed two-thirds of their support for.
But tonight’s vote will only require a simple majority to pass – just over half.
Analysis: Labour’s election move sparks backlash
By Tom Rayner, political correspondent
Labour’s decision to back a December election has been fraught, but the positioning of the Liberal Democrats and SNP in the last 48 hours meant that when Jeremy Corbyn woke up this morning he was the only leader of a major party not committed to an approach that could feasibly lead to a pre-Christmas vote.
Having spent months demanding an election prior to this moment, the Labour leader clearly decided that was politically unsustainable.
But it is a decision that has provoked a backlash in the parliamentary party, and is understood to be opposed by a number of shadow cabinet members.
Whether that backlash will result in rebellious parliamentary manoeuvres and amendments significant enough to scupper what looks like an inevitable election is highly questionable.
Political reporter @breeallegretti Labour has thrown its weight behind an early general election, significantly boosting the chances of voters going to the polls before Christmas. Leader Jeremy Corbyn dropped his opposition to a snap election after the EU granted a Brexit delay until 31 January 2020 to avoid a no-deal divorce.