ITV News Political Editor Robert Peston reports on a tense situation facing the prime minister even if he wins the no-confidence vote
Boris Johnson is awaiting news of whether he will continue as prime minister or not, after Conservative MPs voted in a confidence motion whether they would oust him as their leader.
Earlier in the day the PM pleaded with Tory MPs for support ahead of the confidence vote - which was held between 6pm and 8pm - telling them "now is not the moment" to remove him. The outcome of the vote is expected at around 9pm.
Mr Johnson pledged to lead his party "to victory again" as he urged MPs on the 1922 Committee - a group which represents backbench Tories - to avoid a "pointless fratricidal debate" about the future of the Conservative Party.
The prime minister told them they should "refuse to gratify our opponents by turning in on ourselves".
ITV News Deputy Political Editor Anushka Asthana reports on the views of backbench Conservative MPs
Despite some MPs saying the mood in the room was positive, the PM failed to convince all his colleagues, with Steve Baker, a senior and influential backbencher walking out of the meeting before it concluded, telling journalists waiting outside the room that he would be voting against the prime minister.
Mr Johnson spent 27 minutes persuading Tory MPs to back him in tonight's poll after it was revealed this morning that the threshold of 54 demanding a confidence vote had been passed.
Earlier in the day, Mr Johnson spoke to President Volodymyr Zelenskyy, and told his backbenchers that the Ukrainian leader said he wanted a “strong UK” as the pair discussed Russia's invasion.
But a snap survey carried out by Tory website Conservative Home, which found 55% of party members want the prime minister removed, might have more influence over them.
Mr Johnson has been seeking to shore up support since the vote was announced but it is appearing more difficult than he may have hoped.
As voting got underway John Lamont, a parliamentary private secretary to the foreign secretary, revealed he had stepped down from his role in order to vote against the PM.
PM dealt three huge blows ahead of no confidence vote
The prime minister was dealt three highly damaging blows ahead of the vote, as more and more backbench Tories revealed they would be be voting to remove him.
Senior Tories Jeremy Hunt and Douglas Ross both revealed they would be voting against the PM tonight, while another Tory MP resigned as a government adviser saying he would do the same.
Mr Hunt's intervention - a tweet announcing that he would be "voting for change" tonight - is being considered as the most significant so far.
The former foreign and health secretary, who is perhaps the most influential of all backbench Tory MPs, urged his colleagues in a tweet to "reflect that the consequence of not changing [leader] will be to hand the country to others who do not share those values".
"Today’s decision is change or lose. I will be voting for change," he added.
Mr Ross, leader of the Scottish Conservatives said he'd listened to his constituents in Moray and concluded that he "cannot in good faith support Boris Johnson".
ITV News UK Editor Paul Brand said Mr Ross's decision presents a "major signal that other Scottish Tory MPs are likely to do the same".
And John Penrose resigned from his role as the government's anti-corruption tsar ahead of the vote, saying the he hopes the PM will step aside.
Mr Penrose said it had become "pretty clear" that Mr Johnson had broken the ministerial code after Sue Gray - the civil servant who investigated Downing Street's numerous lockdown parties - condemned a "failure of leadership" under the PM's watch.
"That’s a resigning matter for me, and it should be for the PM too. Here’s my letter to him explaining why," he added.
Those attacks will damage the prime minister's chances of winning tonight's vote, but the odds are still stacked in the PM's favour due to his huge majority.
Number 10 said Mr Johnson "welcomes" a vote of no confidence as it presents a chance to "draw a line and move on".
It comes after Sir Graham Brady, chair of the 1922 Committee of backbench Tories, announced on Monday morning that at least 15% of Conservative MPs had written to him demanding a vote.
More than the threshold of 54 MPs are understood to have submitted no confidence letters but it would require 180 of them to vote against the prime minister in order to oust him - meaning that scenario is highly unlikely.
Prime Minister Johnson writes to Tory MPs seeking support for tonight's vote
Mr Johnson wrote to all Tory MPs after the forthcoming vote was announced, telling them they "have the chance to end weeks of media speculation and take this country forward".
He appeared to acknowledge the scandal that has landed him in this position - the Partygate saga - referring to it as "the media’s favourite obsession".
"Tonight is the moment to draw a line under the issues our opponents want us to talk about," he said, adding: "I know that over recent months I have come under a great deal of fire, and I know that experience has been painful for the whole party.
"Some of that criticism has perhaps been fair, some less so. Where there have been valid points, I have listened and learned and made significant changes.
"And I will of course continue to listen and learn from colleagues about the improvements you wish to see. But I cannot stress too much that we have a golden chance to put this behind us now."
Number 10 said: "Tonight is a chance to end months of speculation and allow the government to draw a line and move on, delivering on the people’s priorities.
"The PM welcomes the opportunity to make his case to MPs and will remind them that when they’re united and focused on the issues that matter to voters there is no more formidable political force.”
Health Secretary Sajid Javid told ITV's Good Morning Britain that he's "confident" Mr Johnson will win the poll but said he understands why many of his colleagues want a rid of their leader.
When is the vote and when will there be a result?
Sir Graham released a statement on Monday morning saying the "threshold of 15% of the parliamentary party seeking a vote of confidence in the leader of the Conservative Party has been exceeded."
The vote is being held between 6pm and 8pm and the votes will be counted immediately afterwards. The result will be made public at 9pm.
It comes after a steady stream of Tory MPs called publicly for the PM to stand down in the wake of Sue Gray’s report into breaches of the Covid regulations in No 10 and Whitehall.
On the Monday after the long Jubilee weekend, Jesse Norman became the latest Tory MP to announce that he had submitted a letter to Sir Graham.
In a letter to the prime minister posted on social media, Mr Norman, the MP for Hereford and South Herefordshire, said Mr Johnson had presided over “a culture of casual law-breaking” in No 10 and that his claim to be vindicated by the Sue Gray report was “grotesque”.
The former minister said Mr Johnson’s current policy priorities were “deeply questionable” and that there were no circumstances in which he could serve in a government led by him.
Which Tories say they will back the prime minister in tonight's vote?
Responding to Conservative MP Jesse Norman's statement, Sajid Javid said MPs are "entitled to their views" but said he would be encouraging colleagues to "rally around the prime minister".
Cabinet colleagues did exactly that on social media after it was announced there would be a vote, including those who have been tipped to replace him.
That includes Chancellor Rishi Sunak, who was once the favourite to take Mr Johnson's job before a drop in popularity, Foreign Secretary Liz Truss and Education Secretary Nadhim Zahawi.
Ms Truss tweeted to say "the prime minister has my 100% backing in today's vote and I strongly encourage colleagues to support him".
"He has delivered on Covid recovery and supporting Ukraine in the face of Russian aggression. He has apologised for mistakes made. We must now focus on economic growth."
Mr Sunak wrote on Twitter: "From the vaccine rollout to our response to Russian aggression, the PM has shown the strong leadership our country needs.
"I am backing him today and will continue to back him as we focus on growing the economy, tackling the cost of living and clearing the Covid backlogs."
Mr Zahawi told his colleagues that "people do not vote for divided teams" as he urged them to "get behind him" the prime minister.
Brexit Opportunities Minister Jacob Rees-Mogg, one of the PM's most staunch supporters, told ITV News he believes a majority of just one vote will be enough for him to remain leader.
He predicted Mr Johnson will "win and it will business as normal" as he backtracked on previous comments, made following Theresa May's no confidence vote in 2018 when he said her majority of 83 was a "very bad result".
"I obviously want the prime minister to get as big a majority as possible, I think that would be helpful and it would close this matter down between now and the next general election, which would be good for the country, good for the Conservative Party, but one is enough."
Asked whether this means he believes Mr Johnson would have a "clear mandate" to rule if he won by such a small majority, Mr Rees-Mogg said: "To be absolutely clear, the answer is yes."
Foreign Office minister James Cleverley tweeted: "I'm not going to go flaky on him now."
Northern Ireland Secretary Brandon Lewis said the Prime Minister has his "full backing", adding: "He got the key big decisions right... he has apologised for mistakes made, and we owe it to our constituents to focus on delivering to make lives better."
Work and Pensions Secretary Therese Coffey tweeted: "PM has got the big calls right - Covid, Ukraine, jobs, levelling up mission, cost of living help (and) he got Brexit done."
Communities Secretary Michael Gove voiced his support for the prime minister, tweeting: "I'll be voting for Boris this evening. The PM got the big decisions right on Brexit and Covid.
"We need to focus now on defending Ukraine, driving levelling-up and generating growth. We need to move past this moment and unite behind Boris to meet these challenges."
Business and Energy Secretary Kwasi Kwarteng posted: "Brexit done, vaccine rollout, record low unemployment, Ukraine response - the Prime Minister has got the big calls right and I will back him enthusiastically in today's vote."
Defence Secretary Ben Wallace tweeted: "On Covid, on Ukraine he has helped deliver a world leading response. He has my full confidence."
Transport Secretary Grant Shapps tweeted: "With the cost of living rising, war in Europe and an economy to recover after Covid, now is not the time for a distracting and divisive leadership contest.
"(Boris Johnson) has my support - we must back him to get on with the job of delivering for the British people."
After listing action taken by the prime minister on Brexit, Ukraine and Covid, Culture Secretary Nadine Dorries tweeted: "Every big decision bang on. He has my vote."
Many Conservative backbenchers have also voiced their support for Mr Johnson, with Beaconsfield MP Joy Morrissey describing Monday's vote as "a self-indulgent distraction the only effect of which will be to embolden a pitiful opposition".
Others including Rachel Maclean, Mark Jenkinson, Stuart Anderson, Simon Clarke and Will Quince also said they will be backing the Prime Minister.
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What is the process for backbench Tories to remove their leader?
Tory MPs are able to force a vote of no confidence in their leader if they won't resign.
To do so requires 15% of the parliamentary party to submit letters of no confidence to the 1922 Committee, which is effectively a HR department for backbenchers.
It takes 54 letters of no confidence to trigger a secret ballot, with a simple majority required for either side to win.
If more than 50% of Tory MPs vote to remove him, he will lose his role of party leader and be barred from competing in the forthcoming leadership election.
If the leader wins over half the votes, then they remain party leader and are given a year's immunity from any further confidence votes.
If a party leader loses a confidence vote then they will be banned from standing in the forthcoming contest and MPs from across the party can be nominated as potential replacements.
The 1922 Committee will determine how many nominations an MP will require to appear on the ballot.
If more than two qualify then MPs will vote on their preference, leaving two final candidates who must then appeal to party members for votes before being elected leader.
What are their chances of ousting Boris Johnson?
The odds are stacked in the prime minister's favour for tonight's vote because of his huge majority.
As he said in his letter to MPs, in 2019 he "won the biggest mandate for the Conservative Party in 40 years".
By bulldozing Labour's red wall, his popularity gifted many Tory MPs a seat in the House of Commons for the first time and many will feel they still owe the PM.
Even if more than 54 MPs submitted letters calling for a vote, it would take a huge 180 of them to agree he should be removed in order to elect a replacement.
Given that so few called on him to go, even after he was fined by the police, it appears rather unlikely more than half of the parliamentary party would suddenly decide they want rid of him as soon as the ballot takes place.