Here's everything you need to know
Earlier this morning, Sir Graham Brady (chairman of the 1922 committee of backbench Conservative MPs) announced that the Prime Minister will face a vote of no confidence.
The ballot, which will take place between 6pm and 8pm this evening, has been triggered by 54 Conservative MPs who have all submitted letters of no-confidence in the party leader. Tory rebels have highlighted "casual law breaking" as one of the reasons for the vote.
Sue Gray's damning report following Downing Street parties and allegations that the Prime Minister misled parliament are just two of the arguments being cited by backbenchers.
Johnson needs at least 180 votes in support of his leadership to remain in office. The party leader is set to address backbench MPs at 4pm this afternoon to rally support. It's thought that he will cite his government's reaction to coronavirus, the Covid-19 furlough scheme and the war in Ukraine as key examples of his leadership success.
What happens in a vote of no-confidence?
Before the secret ballot goes ahead, it's useful to know exactly what happens during a no confidence vote.
To trigger a vote that removes their leader, 15% of sitting MPs have to write a letter to the chairman of the 1922 committee saying they no longer have confidence in their leader. In order to remain in his position, Boris Johnson needs half of his MPs plus one to support him. If he wins, he is safe from challenge for a year.
If the Prime Minister does not secure this simple majority, a leadership contest will follow. Mr Johnson will not be able to run in this.
The announcement of the vote has sent Whitehall into frenzy with MP John Penrose (the government's anti-corruption tsar) resigning and former health secretary Jeremy Hunt saying he will "vote for change".
Despite this, many members of the cabinet have said that they will back the Prime Minister. Speaking to the BBC Deputy Prime Minister Dominic Raab says there is a "very clear" majority who want Johnson to continue. He notes that the ballot is a chance for the Partygate controversy to be put to bed.
A statement from No10 reads: “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."
The results of Boris Johnson's no-confidence vote will be released at 9pm this evening.
