MPs are debating Boris Johnson's proposal to hold an early general election after he was defeated in the Commons on a key vote designed to block no-deal at the end of October.
After the debate MPs will vote on whether to hold the snap poll or not, but Mr Johnson looks set to be defeated for a third time in 24 hours as Labour leader Jeremy Corbyn has said his party will not back it.
Two-thirds of MPs will need to vote for an election for one to be held.
The Prime Minister's call for the country to head to the ballot box came after MPs voted to prevent a no-deal Brexit on October 31, by 327 votes to 299, a majority of 28.
The Bill will now be debated in the House of Lords and needs Royal approval before it can become law.
If the Bill is passed in full the PM will be forced to request a delay to Brexit, unless there was a deal or Parliament explicitly backed leaving the EU without one by October 19.
Mr Johnson told the Commons: "The country must now decide whether the Leader of the Opposition, or I, go to those negotiations in Brussels on the 17th October to sort this out."
The PM put pressure on Jeremy Corbyn to get Labour to back a vote for an early general election.
But both Labour and the Liberal Democrats have said they will not back the motion - which requires a two-thirds majority - until chances of a no-deal Brexit were taken off the table.
Mr Corbyn said the Bill must be passed through the Lords and have received Royal Assent before he will entertain the thought of a general election.
"The Prime Minister says he has a strategy but he can't say what it is and can't tell the EU either - the truth is that there really is nothing there."
Mr Corbyn continued: "We want an election as we look forward to turfing this Government out."
He likened Mr Johnson's offer of a general election on Tuesday, October 15, to "the offer of a poisoned apple to Snow White by a wicked queen".
Mr Johnson, opening a debate on triggering an early general election, said: "I think it's very sad that MPs have voted like this, I do, I think it's a great dereliction of their democratic duty.
"But if I'm still Prime Minister after Tuesday October 15 then we will leave on October 31 with, I hope, a much better deal."
Mr Johnson claimed the House had voted to "scupper" serious negotiations and said the Bill is "designed to overturn the biggest democratic vote in our history, the 2016 referendum".
He added: "It is therefore a Bill without precedent in the history of this House seeking as it does to force the Prime Minister with a pre-drafted letter to surrender in international negotiations."
Following a moment of confusion, an amendment to the Bill seeking to give MPs a vote on Theresa May's final Brexit deal was also passed.
Labour MP Stephen Kinnock's amendment was approved after tellers for those voting against the amendment were not put forward during voting.
A Government source said it was a "free vote so no one put tellers in".
Mrs May's final offer, the Withdrawal Agreement Bill, emerged from cross-party talks earlier this year, but was never put before Parliament because she was ousted as Tory leader.
On Wednesday, Tory former Cabinet minister Dame Caroline Spelman became the latest MP to rebel against the Government, when she backed the Bill aimed at blocking no-deal at its second reading, but will not have the party whip withdrawn.
Some , including former chancellor Phillip Hammond and ex-justice secretary David Gauke, have had the whip removed after voting against the government on Tuesday, when they backed a vote calling for Parliament to take control of Wednesday's events.
Tory Chief Whip Mark Spencer said at the moment he has no regrets about sacking his colleagues.
He told ITV News Political Correspondent Paul Brand it was "about party discipline and making sure MPs support the prime minister".
A Downing Street spokesperson earlier said the PM will not resign to force the country to head to the polls if the Government lost the Commons vote on an election, telling a Westminster briefing: "He's not going to step down.
"He wants an election.
"We will find a way to deliver on what the British people want, which is to deliver Brexit by October 31.
"If the PM cannot get the Bill through Parliament because Parliament is determined to wreck the negotiations, the only other option then is a general election."
The spokesperson refused to say what steps the Government would take to secure a general election if it loses a vote on calling a ballot, but said Mr Johnson believes going back to the public is the only option if Parliament votes to delay Brexit.
Mr Johnson said he was ready for an election but that Mr Corbyn was scared to face him and the country.
At one stage, he taunted Mr Corbyn that "there is only one chlorinated chicken in this House and he's on that bench" - referencing a potential trade deal with the US.
As a bruised Mr Johnson sought to wrestle back some measure of control over his splintered party, he said his strategy was to get a deal by the summit on October 17 and "to get Brexit done".
He added: "What his surrender bill would do is wreck any chance of the talks and we don't know his strategy at all."
Announcing his decision, Lord Doherty said the decision on proroguing Parliament was for politicians, and not for the courts.