The UK is set to head to the polls on December 12 after MPs backed the government’s proposed move to break the Break deadlock.
MPs voted in favour by 438 to 20, a huge majority of 418, during the legislation’s crucial third reading in the House of Commons.
It comes after the bill passed its second reading without the need for a formal vote as it had the clear support of the main parties.
While it still needs to pass through the House of Lords before it is official, political parties moved to an election footing as soon as the result was announced.
Just moments after the vote, the PM told Tory backbenchers at the 1922 committee in Westminster to “take the fight to Corbyn” as MPs enthusiastically banged on the desks.
But leaving the room, Johnson attempted to play down the Conservatives’ chances of victory, despite some polls putting his party ten points in the lead.
“It is going to be a tough election but we will do the best we can,” he said, as reporters swooped on him to ask questions.
Tory MP Robert Halfon said the response in the room to the PM was “incredible”, adding: “He told MPs he is going to take the fight to Corbyn on schools, on hospitals and on the police. It was like Henry the Fifth at Agincourt.”
Halfon said that Johnson did, however, admit that the election was a risk and that victory was not certain.
“He did say forget about the polls and everything else you have read, this is going to be a tough election - perhaps our toughest yet.”
MPs earlier rejected Labour’s amendment to move the date to December 9 by 315 votes to 295, a majority of 20.
The next election was not scheduled to take place until May 2022.
Johnson said he wants an election to secure a majority and a “new mandate” from voters to get his Brexit deal through the Commons and take the UK out of the EU by January 31.
Labour leader Jeremy Corbyn backed the snap election following a meeting of his shadow cabinet on Tuesday morning. The Labour leader gave the go-ahead now a no-deal Brexit on October 31 was “off the table”.
After the crucial vote, Corbyn said: “This election is a once-in-a-generation chance to transform our country and take on the vested interests holding people back.
“The choice at this election could not be clearer. A Labour government will be on your side, while Boris Johnson’s Conservatives – who think they’re born to rule – will only look after the privileged few.
“We will now launch the most ambitious and radical campaign for real change that our country has ever seen.
“This is our chance to build a country for the many not the few and fit for the next generation.”
Johnson’s decision to call a poll came after the Lib Dems and SNP said they would help facilitate the early poll. The two parties have said getting more pro-Remain MPs elected is the only way to stop Brexit.