Former deputy prime minister Lord Heseltine predicts a "substantial crisis for the Tory Party".

Image source, EPA

Asked by the BBC at the European Parliament in Strasbourg for a message to MPs ahead of the meaningful vote, European Commission President Jean-Claude Juncker said: “I would like them to behave in a responsible way.”

On Monday, the prime minister published a joint letter, external from European Council President Donald Tusk and Mr Juncker in which they stressed their "firm commitment" to working towards an agreement.

They also said that if the controversial backstop - the fallback plan to avoid any return to physical Northern Ireland border checks - were to be used it would be for the "shortest possible period".

However, they said they could not add anything to change the terms of the deal negotiated with Mrs May.

Reality Check

In the run-up to the vote, Theresa May has tried to reassure MPs in the Commons over the controversial "backstop" - the fallback plan to avoid any return to physical border checks between Northern Ireland and the Republic of Ireland after the UK leaves the EU.

But what is the backstop and why does it matter for Brexit? Reality Check's Chris Morris explains.

Leave-supporting Kate Hoey debates Brexit with the SNP's Kirsty Blackman and Labour's Chuka Umunna on the Victoria Derbyshire Show.

Labour MP Chuka Umunna - a backer of the People's Vote campaign - said his party should commit to a further EU referendum by the end of this week.

Speaking at College Green, he said he expects a "heavy defeat" for Theresa May's deal ahead of a vote of no confidence in the prime minister on Wednesday.

"It's probably unlikely that the prime minister will lose that vote of no confidence and therefore we need to move to the next stage in the Labour Party's confidence motion, and that is to without delay commit to a People's Vote as the way out of this, and to do that by the end of this week," Mr Umunna said.

"I think undoubtedly the current deal we have as a member of the European Union must be on that ballot paper and some form of hard Brexit that satisfies leave voters on that kind of Brexit."

Image source, PA

BBC Radio 5 live

Emma works part-time in Llanelli and spends the rest of the week as a carer for her mother who suffered a stroke a couple of years ago.

Emma voted Remain, her brother Stephen voted Leave.

She told 5 Live reporter Rory Carson that she would like another referendum: “Coming out of the EU, the transport and people [companies] are pulling out and moving to Germany. I think it’s no good for the UK. A lot of people are losing jobs already… I do believe this is a big mistake leaving… Theresa May is not strong enough.”

Stephen said: “I’d rather be out, because I think it’s for the best. We might suffer, [but] in the long run we’ll be better off… You’ve got the construction industry which is creating a lot of jobs as well, they’re going to be building down here soon."

Click to listen live.

The BBC's assistant political editor Norman Smith says the People's Vote campaign is meeting with Labour leader Jeremy Corbyn's staff in an effort to persuade him to back a new referendum if the PM's deal is defeated.

Image source, Reuters

Scottish Secretary David Mundell has spoken out in favour of Theresa May's deal, but several of his Scottish Conservative colleagues have indicated they will be voting against it due to concerns over the future of the union and the fishing industry.

But Mr Mundell told BBC's Good Morning Scotland that even if the government loses the vote, MPs should vote again.

He said: "The obvious option following this vote - if it wasn’t to go through - is to revisit the vote. I don’t want to see a situation where there are repeat votes.

"I do see that there are a number of people who clearly want in the vote tonight to register their position and view on the deal, but I hope that if there is another vote on this their actual thought process will be one of: ‘What are the alternatives?’."

Former UKIP leader Nigel Farage says he would run for parliament again, if the UK did not leave the EU.

Speaking on the Jeremy Vine on 5 show, he said: "I don't want to, I'm a businessman. I came into politics because I felt so strongly about this issue, I’d much rather never be involved in politics again. Brexit gets delivered, we get on with our lives.

"But I fear I’ve got a few more battles to fight."

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Brexiteer Jacob Rees-Mogg explains why he is voting against his prime minister's deal:

Senior Labour MP Hilary Benn says he expects Jeremy Corbyn to call for a vote of no confidence in Theresa May "very quickly", if the prime minster loses today's vote.

He said: "I would assume that a vote of confidence would come very quickly but it is a decision for the shadow cabinet to take and we will see as a result of that vote whether there’s the possibility of a general election, which we would like."

If Labour cannot force an election, Mr Benn says May should go back to parliament to try and find a deal that can win a majority.

The chair of the Exiting the European Union Select Committee says he would support a second referendum if all parliamentary procedure had been exhausted.

Image source, AFP

Zoe voted to remain in the EU, yet many of her friends voted to leave, and she invited her mates and some customers to her chip shop in Hull to talk about their differences:

Democratic Unionist Party leader Arlene Foster has her say on this evening's vote:

BBC Radio 5 live

5 Live’s Your Call programme asked: What’s your message to your MP?

Annette in Portishead said: “As far as I am concerned I will be leaving on the 29th of March. How can we move on as a country when we have a lot of MPs who didn’t tell the truth before the last referendum?

"They’ve left our country in a state of turmoil, and the anger has left us so volatile, the debates are so contentious and quite nasty at times and I need to remove that toxicity from my life. The easiest way for me to do that is to stand back … I just want life to get back to normal.”

Christine in Stratford-upon-Avon said: “I would like my MP to vote for this deal tonight, because I want to leave. I would prefer a no deal leave but I don’t think that’s going to happen… I think at the moment we’ve just rolled over, and I’m absolutely furious. We’ve just accepted everything.”

Kathleen in Durham said: “I want my MP not to vote for Theresa May’s deal today. I am in a constituency where they voted to come out, and I wanted to stay in.

"I feel it will be detrimental for our constituency, our region, our country. We’ll see what happens today and we’ll take it from there. I would really like another vote - I feel a lot of people now know what it entails.”

Click to listen live on BBC Sounds.

Join the discussion:Text 85058 @bbc5live , external

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About 100 Conservative MPs - and the Democratic Unionist Party's 10 MPs - could join Labour and the other opposition parties to vote it down.

However, five Conservative Brexiteer MPs who have been critics of the withdrawal agreement have now said they will support the government, along with three Labour backbenchers and independent Frank Field.

When asked what the margin of defeat could be for Mrs May, former Downing Street director of legislative affairs Nikki da Costa told the Today programme she expected it to be within the "50 to 80 mark".

Victoria Derbyshire

Adam Fleming
Brussels reporter

Speaking in the European Parliament, Austrian Chancellor Sebastian Kurz has said that the EU has nothing to “reproach itself” for over the Brexit deal.

“Even if things don’t go our way in the vote in the British Parliament this evening and even if the next few weeks and months are rocky it is important that we continue to sing from the same hymn sheet," he said.

“Austria will do everything it can to support that line.”

Image source, EPA

Children's Minister Nadhim Zahawi explains why he is backing Mrs May's deal, and calls on his colleagues to do the same.