Labour has tabled a no-confidence vote in the government after Theresa May's Brexit deal was comprehensively voted down by Parliament.
Here are the latest developments:
Brexit deal defeated by majority of 230
Government suffers biggest Commons defeat since WWI
Theresa May says government 'will listen'
Labour tables no-confidence vote
Government will make time for no-confidence vote on Wednesday
Under the terms of an amendment passed last week, Mrs May must table a motion on her Plan B by January 21.
Reacting to the result, she said: "The House has spoken and the Government will listen."
Jeremy Corbyn described the defeat as "catastrophic", and said that Labour would table a vote of no-confidence in the government.
There were calls to extend Article 50 from the SNP and a call for a People's Vote from the Liberal Democrats.
ITV News Political Editor Robert Peston said the defeat meant that Mrs May's deal was "in essence dead".
And ITV News Political Correspondent Carl Dinnen said that the European Union would be unlikely to offer further concessions considering the scale of the defeat.
But the option to extend Article 50 is something that is being seriously considered in Brussels, according to ITV News Europe Editor James Mates.
Mrs May earlier made a last ditch attempt to win support from MPs in the Commons.
Wrapping up a final debate, the prime minister predicted the vote would be a "historic decision" which would "set the future of our country for generations".
She told the House: "I believe we have a duty to deliver on the democratic decision of the British people, and to do so in a way that brings our country together."
The prime minister is now expected to go back to Brussels in another bid to win further concessions.
With Britain set to leave the EU in just 73 days, Mrs May also offered cross-party talks with MPs to determine a way forward.
Mr Corbyn tabled the no-confidence vote immediately after the result was announced.
But Peston predicted the party would "almost certainly" lose the vote, which will take place on Wednesday.
Speaking of the prime minister, the Labour leader said: "At every turn the prime minister has closed the door on dialogue....In the last two years she's only had one priority - the Conservative Party.
"Her governing principle of delay and denial has reached the end of the line."She cannot seriously believe that after two years of failure she is capable of negotiating a good deal for the people of this county."
Which Conservative MPs voted against the deal?
Former Ukip leader Nigel Farage called on Mrs May to step down, claiming she had showed a "catastrophic failure of leadership".
"If she has any sense of honour then she will resign," he tweeted.
Ex-foreign secretary Boris Johnson told ITV News that he believed there was time to negotiate a new Brexit deal with the EU before March 29.
But EU Commission president Jean-Claude Juncker indicated that this may not be the case.
"I take note with regret of the outcome of the vote in the House of Commons this evening," he tweeted.
"I urge the UK to clarify its intentions as soon as possible. Time is almost up."
And Donald Tusk tweeted: "If a deal is impossible, and no one wants no deal, then who will finally have the courage to say what the only positive solution is?"
Scotland first minister Nicola Sturgeon called for the Article 50 process to be halted and a second referendum held to avoid the UK crashing out without a deal.
"It has been crystal clear for months that the prime minister's approach was heading for a crushing defeat," she said.
"Instead of facing up to that fact, she wasted valuable time with her postponement of the meaningful vote in December. There is no more time to waste."
Transport secretary Chris Grayling defended the government's deal despite the heavy loss and insisted it is unthinkable to have a second referendum.
“I think the idea to go back to 17.4 million people and say to them - 'you know you voted to leave, well actually, we're not going to let this happen' is completely unsustainable", he said.
"Equally, those who are concerned about no deal, we are preparing for no deal, it's right and proper that we are. But it's much better for this country if we leave with a partnership with an agreement and friendly neighborhood relationship with the European Union for the future - that's the best deal for this country.”
Conservative MP for Loughborough Nicky Morgan told ITV News that a red line has now been drawn for the Prime Minister.
"If she (Theresa May) wants an agreement that's going to get a majority of MPs, she is going to have to get something that commands a consensus across the House of Commons", she said.
Prominent Brexiteer Jacob Rees-Mogg MP told ITV News that despite the loss inflicted by the House, Brexit is still alive.
“The Prime Minister is still committed to Brexit, and it's easier said than done for the House of Commons to take over as the executive.
"Our system has a separation between the executive and the legislature and possibly the House of Commons could set a new timetable but the Government could then parade Parliament at which point the legislation is on route, falls.”
ITV News National Editor Allegra Stratton was in Sunderland where 61% voted to leave to ask the people what they thought of today's events
ITV News Correspondent Rachel Younger asks the people of remain-voting Bristol what they hope will happen next
Speaker John Bercow appeared to suggest he would allow a vote on extending Article 50 if enough MPs pushed for it.
Labour's Yvette Cooper had asked him: "Can you advise the House on what we might be able to do to urge the Prime Minister, for the sake of businesses and jobs and people across the country, to seek an immediate extension of Article 50 now so that this can be sorted out?"
Mr Bercow said: "This will be discussed I'm sure in the days ahead on the floor of the house."
He added: "Of one thing I am sure; that which members wish to debate and which they determine shall be subject to a vote, will be debated and voted on. That seems to me so blindingly obvious that no sensible person would disagree with the proposition.
"If MPs want to debate a matter and to vote on it, that opportunity I'm sure will unfold in the period ahead."