An emergency debate aimed at blocking a no-deal Brexit is raging in the House of Commons after at least 10 Conservative MPs rebelled against the government.
Despite the threat of deselection, the Tory rebels rose to their feet in support of the emergency debate application, moved by colleague Sir Oliver Letwin.
Labour MPs described the "powerful" scenes, after senior Tories including former chancellor Phillip Hammond and Rory Stewart confirmed they would put their jobs on the line to secure a vote.
Success in securing an emergency debate means MPs will vote on whether to control the Commons agenda on Wednesday.
If MPs seize the Commons order paper, votes will be held intended to force the PM into requesting a Brexit extension from the EU.
However Mr Johnson has promised if he loses tonight's vote, he will call a general election for mid-October and deselect any Tory to oppose him.
Despite it being Labour policy to demand a general election, it might not be guaranteed when the prime minister seeks to hold one.
Emily Thornberry, the shadow home secretary, told ITV News: "There's not going to be a general election tomorrow, because we're not going to vote for it, because we have to make sure this legislation (blocking no deal) has been embedded."
Opening the emergency debate, Sir Oliver said: "Over the last six weeks the government has not produced a single indication of any viable proposal to replace the backstop by any alternative likely to prove acceptable to the EU.
"The likelihood of the Government reaching a deal at the council meeting on October 17 and 18 on the terms the Government itself has set is accordingly slight."
Sir Oliver added this was the last week Parliament will have to block a no-deal exit on October 31, noting: "It's decision time."
Aside from Brexit, the biggest talking point of the debate was the body language of Leader of the House of Commons, Jacob Rees-Mogg, who was told to "sit up" by MPs.
Green Party MP Caroline Lucas said Mr Rees-Mogg's body language was "so contemptuous of this House and of the people".
Addressing him directly in the Commons, Ms Lucas said: "For the benefit of Hansard, the Leader of the House has been spread across around three seats, lying out as if that was something very boring for him to listen to tonight."
Former Tory-turned-independent MP Nick Boles, who was driven to vote for the Article 50 Bill in the chief whip's car having just undergone chemotherapy, gave an impassioned speech to the Commons.
Mr Boles, who left the Conservative party in April, said he was able to "hold his head high" after leaving the party.
Mr Boles told the Commons: "To those brave souls on the Conservative benches who face expulsion from the party for voting for the motion today, I say this: your country needs you.
"Do what you know to be right.
"Join me on these benches and, together, let us build a new force in British politics and a true home in Parliament for those who believe in one nation."
Some of the most amusing moments from the debate came from Tory grandee Ken Clarke, who mocked Leader of the House Jacob Rees-Mogg.
After Mr Rees-Mogg criticised the night's debate as "unconstitutional" for disregarding conventions, Mr Clarke quipped "he's coming out with arguments that are almost incredible".
As MPs battled traded blows in the Commons, hundreds of anti-Brexit protesters chanted on Westminster Bridge.
It came after former Tory MP Phillip Lee wiped out Boris Johnson's working majority as he crossed the House to join the Liberal Democrats.
In a statement, the former justice minister said: "This Conservative Government is aggressively pursuing a damaging Brexit in unprincipled ways.
"It is putting lives and livelihoods at risk unnecessarily and it is wantonly endangering the integrity of the United Kingdom."
Earlier in the day Mr Johnson told the Commons legislation aimed at blocking a no-deal Brexit, he said, would "force me to go to Brussels and beg an extension" and "destroy any chance" of negotiating an agreement.
He said any Conservative who voted against him would have the whip removed.
Former chancellor Phillip Hammond - who along with David Gauke and Sam Gyimah confirmed he would vote against the government - said he feels "a sense of outrage" at the prospect of being deselected.
"I would be extremely disappointed if Boris Johnson's government were to withdraw the whip from me and others who vote for this Bill tonight," he said.
He added: "I don't recognise the right of these people who have taken over in our party."
In the Commons Mr Johnson insisted he would never "surrender" control of the Brexit negotiations to Brussels, in reference to legislation aimed at blocking a no-deal Brexit on October 31.
"It would enable our friends in Brussels to dictate the terms of the negotiation. That's what it does. There is only one way to describe this deal: it is Jeremy Corbyn's surrender bill," he told the Commons.
"It means running up the white flag... I want to make clear to everybody in this House there are no circumstances in which I will ever accept anything like it.
"I will never surrender the control of our negotiations in the way the Leader of the Opposition is demanding."
Speaking in the Commons, Labour leader Jeremy Corbyn said it was becoming increasingly clear "this reckless Government only has one plan - to crash out of the EU without a deal".
He added: "No-deal will mean food shortages, reduced medical supplies and chaos at our ports. Not me, not me saying that. The Government's own leaked analysis says."
Mr Corbyn said: "He isn't winning friends in Europe, he's losing friends at home. His is a Government with no mandate, no morals and as of today no majority."
He had earlier said he fully expected the no-deal Brexit prevention legislation to be passed by Parliament.
Former Tory leadership rival Michael Gove, now Chancellor of the Duchy of Lancaster, pleaded with colleagues to give Mr Johnson "time and space" to work on a potential deal.
He said: "The response that the Prime Minister has received from European leaders shows that they are ready to move - they want a deal too.
"And they are moving because the Prime Minister has been clear that matters must be resolved by October 31.
"If we drift then the incentive on them to deliver will quickly dissipate."
The no-deal planning minister told MPs: "There are undoubted risks and real challenges in leaving without a deal on October 31.
"But there are also opportunities and new possibilities for our country outside the EU.
"Operation Yellowhammer assumptions are not a prediction of what is likely to happen, they are not a best-case scenario or a list of probable outcomes they are projections of what may happen in a worst-case scenario."
He said businesses and the public should not be "blithe or blase" about the challenges of Brexit, but that "risks can be mitigated" and "we can be ready".
His pleas came hours after the prime minister gave Tory rebels an "unconvincing explanation" of how a Brexit deal could be reached by October 31, as the MPs sought reassurances on negotiations.
Members of the so-called Gaukeward Squad - including former chancellor Mr Hammond and ex-justice secretary Mr Gauke - met the prime minister earlier in the day having threatened to do whatever it takes to stop a no-deal Brexit.
A source close to the group said the Prime Minister "gave an unconvincing explanation of how a deal could be ratified, legally drafted and legislated in the very short timeframe when Parliament is not prorogued".
The source said Mr Johnson could not give a "reasonable answer" as to why the Government had provided the European Union with its alternative proposals to the Irish backstop.
Following the meeting, minister-turned-rebel Alistair Burt confirmed to ITV News he would not stand at the next general election, after hinting on Monday he would struggle to stand against the Conservatives.
Flowchart lays out what eventualities may lie ahead for Brexit:
An estimated are believed to be ready to vote against the government - despite being threatened with the sack from the party and barred from standing as a Conservative in any upcoming general election.
Rory Stewart tweeted a video explaining that he would be voting against the Government and fellow Tory MP Nicholas Soames - the grandson of Winston Churchill - replied: "#MeToo".
Another rebel, Sam Gyimah, told ITV News he will be voting against the government "to stop no deal and that is because I believe it is the right thing to do".
He said he is prepared to have the whip removed and will stand in the next general election, whether or not as a Conservative.
He said: "I will vote against the Government tonight because it is the right thing to do."
Under the terms of the European Union (Withdrawal) (no 6) Bill, the Government must seek a delay to the UK’s withdrawal from the EU until January 31 if there is no agreement with Brussels in place by October 19 and Parliament has not approved a no-deal Brexit.