- Watch live: MPs hold final day of debate ahead of meaningful vote
Theresa May is braced for a Commons defeat over her Brexit deal on a historic day in Westminster.
A final debate concluded on Tuesday with Mrs May calling on MPs one last time to support her deal.
One amendment to the deal was put to the House beforehand, but it was overwhelmingly defeated with 600 votes against.
The amendment, tabled by Tory MP John Baron, sought to give the UK the right to terminate the Irish border backstop without the agreement of the EU.
Here's everything you need to know on this historic day:
As the final debate in the Commons took place, Mrs May made a last ditch appeal to win supporters.
More than 100 Tory MPs have already declared their opposition to the PM's plan, and there is speculation the Government could go down to one of the heaviest defeats of modern times in the ultimate meaningful vote.
Addressing the Commons, Mrs May said "Our deal delivers certainty for businesses with a time-limited implementation period to prepare for the new arrangements of the future relationship. No deal means no implementation period.
"Our deal protects the rights of EU citizens living in the UK and UK citizens living in the EU so they can carry on their lives as before. No deal means no reciprocal agreement to protects those citizens' rights.
"Our deal delivers the deepest security partnership in the EU's history so our police and security services can continue to work together with their European partners to keep all our people safe.
"No deal means no such security partnership, and our deal delivers the foundations for an unprecedented economic relationship with the EU that is more ambitious than anything they have ever entered into with a third country."
"It will give us the benefits of trading with the EU and the ability to forge new trade deals in our own right."
Confirming that Labour would be voting against the agreement, leader Jeremy Corbyn described the deal as "botched and damaging" for the country.
Mr Corbyn said the government had failed to engage with people and businesses about what kind of Brexit they wanted, and had presented the country with a deal which risked jobs and living standards.
"This deal fails to provide any certainty about future trade," he said.
"It fails to guarantee our participation in European agencies and initiatives. Losing this co-operation undermines our security, denies our citizens opportunities and damages our industries."
Mr Corbyn continued: "The withdrawal agreement is, in short, a reckless leap in the dark.
"It takes our country no closer to understanding our post-Brexit future and neither does the future partnership document."
Ahead of the vote on the prime minister's plan for Brexit Jacob Rees-Mogg told ITV News: "The argument is no longer so much about the form of Brexit, it's about are we still a democracy?"
He added: "People voted to leave, they didn't vote for a deal, they voted to leave, and this deal doesn't actually make us leave cleanly."
DUP leader Arlene Foster accused Mrs May of not trying to get rid of the Northern Ireland backstop in recent discussions with Brussels.
Mrs Foster spoke at a Brexiteer event in London which was also attended by former Brexit secretaries Dominic Raab and David Davis.
She told the audience she had deja vu having come to London to argue against the Withdrawal Agreement before the Meaningful Vote was pulled in December.
"We said to the Prime Minister she had to get rid of the backstop and get a Withdrawal Agreement that can be lived with," Mrs Foster said on Tuesday.
"I don't think she even asked to get rid of the backstop."
She added: "We want the PM to go back to the EU and say 'the backstop must go'.
The deal suffered its first official parliamentary defeat in the House of Lords on Monday night as peers voted by 321 votes to 152 - a majority of 169 - to reject it.
It would appear unlikely Labour can muster enough votes to force a general election, with both Tory rebels and the DUP indicating they would continue to back the Government in a confidence vote.
However Downing Street has given little indication as to how the Prime Minister intends to proceed if she is defeated.
Under the terms of an amendment passed last week, she must table a motion on her Plan B by Monday - although in practice she is unlikely to want to wait that long.
- On Monday ITV News political correspondent Carl Dinnen walked us through how Tuesday's vote will work
Some reports have suggested she could fly to Brussels - possibly as early as Wednesday - in an attempt wring further concessions on the crucial issue of the Northern Ireland “backstop”.
But that could prove problematic if she has suffered a massive defeat, with EU leaders reluctant to give ground if they believe it is simply impossible for her to get the deal through the Commons.
Alternatively, she could to bring back the deal to the House for a second – or possibly even a third – time in an attempt to wear down the opposition.
Some MPs claimed to have detected some movement towards her position after she addressed a private meeting of Conservatives MPs at Westminster on Monday evening.
So far, however, the numbers contemplating backing the deal would appear to fall far short of what is needed to affect the final outcome.