In a tweet, Foreign Office minister Sir Alan Duncan asked: "How has she managed to go through every day taking so much flak from less decent people?"

Meanwhile, reflecting on the moment that Mrs May broke the news to MPs, George Freeman told the BBC: "It was a very sad moment. She has devoted her life to public service.

Mr Freeman - the PM's former policy adviser - added: "She - with tears not far from her eyes - said: 'Tonight this is a moment I promised I would deliver the Brexit withdrawal agreement.

"'I have made many mistakes. I am only human. I beg you, colleagues, vote for the withdrawal agreement and I will go'."

He added: "There was silence in the room and it was incredibly sad."

Arron Banks, businessman and co-founder of Leave.EU, was spotted in Westminster earlier.

Now, he's tweeted a reply to a suggestion that the DUP will come round to back Mrs May's deal, claiming that "they didn't seem that keen at lunch".

The debate on the eight Brexit alternatives selected earlier by Speaker John Bercow has now finished.

MPs will now be given half an hour to go into the voting lobbies and cast their votes for the options they endorse, using paper ballots.

The results will be announced by Mr Bercow later this evening.

Image source, PA

Leading Brexiteer Jacob Rees-Mogg says there is an “element of sadness” about Mrs May’s announcement “even though it's something I've wanted".

Speaking to journalists after the 1922 committee he said he would vote for the government’s Brexit deal if the DUP abstained

“If DUP abstained I would feel entitled to back it. I think if [they are] still against it, I would not feel about to back it," said the Conservative MP.

He said Mrs May had spoken at the meeting in a “dignified way” and he’d always “greatly respected her approach to doing her duty.”

“The PM is incredibly dignified….Although I was involved in the challenge against her last year, there's never any joy or happiness in someone's political career coming to an end, always a poignancy about that.”

He refused to speculate on who would now stand as Conservative leader – but asked what he thought of Boris Johnson he said: “I think Mr Johnson is a formidably able man and I backed him in 2016.”

Asked if he’d back Mr Johnson this time around he didn’t answer.

And he said: “I’m not a gambler so will wait and see… let's leave this as prime minister's day and come on to runners and riders later.

House of Commons
Parliament

Image source, HoC

In the Commons, debate over the Brexit options to be voted on this evening is coming to an end.

Labour's Paul Williams says he will be backing the motion calling for a confirmatory vote on any Brexit deal.

It is time to "bring the public back into our discussions", he says.

Aside from the drama of Mrs May's announcement, MPs have a job to do tonight - vote on eight indicative votes on alternative Brexit options.

Here is what the ballot paper looks like for MPs - a aye/no option for each proposal.

BBC News Channel

Conservative MP Andrew Percy says Brexiteers will "probably vote down all alternatives tonight".

"Tonight is the first of a two part process - it's like the X Factor," he adds.

BBC News Channel

Conservative MP George Freeman says he expects a couple of options to receive the backing of over 242 MPs these evening.

"I hope the penny will drop and MPs will vote to get Theresa May's deal through," he says.

On a preferred choice for the next prime minister, Mr Freeman says "if it is now - it must be a Cabinet hard hitter, a Brexiteer, someone who can unite the Party and govern in the national interest."

He suggests Michael Gove as an option.

Chancellor Philip Hammond has tweeted his support for the PM.

Here is a list of Conservative MPs who have publicly called for May to go before the next phase of the Brexit negotiations:

1.George Freeman

2.Andrew Bridgen

3.Grant Shapps

4.Charlie Elphicke

5.Tim Loughton

6.Esther McVey

7.Phillip Davies

8.Nadine Dorries

9.Ben Bradley

10.John Whittingdale

11.Nicky Morgan

12. Nigel Evans

13. Iain Duncan Smith

BBC News Channel

Housing Secretary James Brokenshire says that Theresa May remained "focused on the task at hand" in her statement to the 1922 Committee.

Her message was that "we need to move on for the country", he adds.

Mr Brokenshire says some of his colleagues wanted to see a change in approach to the next step, and that the PM has shown "a sense of duty before a sense of self".

"You've seen that sense of duty and purpose tonight - she is resolute: this is not about political games, this is about the future of this country," he says.

Theresa May gave a clear message tonight on how we come together and move on, he concludes.

House of Commons
Parliament

Image source, UK Parliament

Former Conservative MP Anna Soubry, now a member of the Independent Group, remarks that a number of her former colleagues have changed their minds on the PM's deal, but want to deny the public the right to do the same with Brexit itself.

This is a "disgrace, verging on hypocrisy", she says, adding that the public are "entitled also to change their mind".

BBC News Channel

The BBC's Europe editor Katya Adler says EU leaders have pressed the UK to say what Brexit they wanted.

Their priority is "to stop the damage of Brexit infecting the rest of the EU".

The EU would really like to get on with this as soon as they can, and to avoid a no-deal Brexit, she says.

"The uncertainty is already damaging international businesses."