MPs supported in overwhelming numbers the Prime Minister’s bill to hold an election on 12 December at the second reading stage - meaning they have given their consent to the general principal of the bill.
An amendment to hold an election on December 9 was narrowly defeated.
Labour had put forward three amendments, one to move the date to 9 December, one to allow 16 and 17-year-olds to vote, and one to allow European citizens living in the UK to vote.
Opposition parties want to bring the date forward to ensure there is not enough time for the Prime Minister to deliver Brexit before an election.
But as the options narrowed over the course of a dramatic day in Parliament, the odds of an election on December 12 became more and more likely.
Jeremy Corbyn announced his backing for the election bill earlier today - less than 24 hours after Labour rejected a similar bill to trigger an election.
The Labour leader said: "No Deal is now off the table so tonight Labour will back a General Election. We're launching the most ambitious and radical campaign for real change our country has ever seen.
“This is a once in a generation chance to build a country for the many, not the few. It's time.”
He added: “We are going out there to fight an election campaign and I can’t wait to get out there on the streets.”
Speaking in the House of Commons on Tuesday, Mr Johnson criticised the opposition leader for changing his mind.
He said: “They just want to spin it out forever, until the 12th of never. And when the 12th of never eventually comes around, they’ll devise one of their complicated parliamentary procedures and move a motion for a further delay and a further extension then.”
The PM has doubled down on his bid for an election after setting aside his pledge to deliver Brexit by 31 October “do or die”.
The plan is now in tatters after the EU agreed to Mr Johnson’s request for a Brexit extension.
What could happen in an election?
The Brexit Party is likely to try and hammer the Tories over Mr Johnson’s pledge that he would “rather be dead in a ditch” than ask for an EU withdrawal delay beyond October 31.
After two very shaky general elections, the Lib Dems have a new, untested, leader in the form of Jo Swinson but have been riding higher in the polls.
The SNP also expect to perform well against the Tories in Scotland.
In 2017, Labour stormed back from 24 points behind in the polls to come close to drawing level with the Conservatives in the popular vote, but since then Mr Corbyn’s image has been rocked by his stance on Brexit and rows over how he has handled allegations of anti-Semitism within the party.
He told LBC on Tuesday that a potential surge in popularity for the Brexit Party or Liberal Democrats could make it harder for either of the two main parties to win a parliamentary majority.
“I will make a prediction,” he said,. “There are going to be a record number of non-Conservative and non-Labour MPs as a result of this election
How could it impact Brexit?
Brexit will be a big flashpoint as the major parties have much more pointed policy stances than they did in 2017.
The Tories would be pushing the amended Withdrawal Agreement Bill (WAB) Mr Johnson secured with Brussels, which all wings of the party have, grudgingly, united behind.
Labour wants to renegotiate that deal and then put the results to a new referendum, and the Liberal Democrats seek to revoke Brexit without the need for a fresh national poll on the issue.
If the Tories secure a majority Mr Johnson could push through his WAB – House of Lords willing – and under the so-called “flextension” agreed with Brussels the UK could quit the EU on December 31, rather than the currently scheduled exit date of January 31.
The European Parliament would also need to ratify the deal before the end of December for this to happen.
What if there’s a hung parliament?
Such a scenario is likely to produce more deadlock. However, with the WAB receiving a healthy majority in its first vote in the current Parliament, such legislation could still pass if the Tories are the largest party.