U.K. Prime Minister Boris Johnson will face a vote of no confidence from his own party Monday night that could oust him from power.

Why it matters: Conservative Party lawmakers have grown increasingly frustrated with Johnson's personal scandals, especially his attendance at lockdown-breaking parties during the height of the COVID pandemic.

• Johnson's "partygate" scandal led to national outrage and made him the first sitting prime minister found to have broken the law.
• He has faced calls to resign since first denying and then later confirming and apologizing for attending a Downing Street garden party.

Driving the news: The vote was announced by Tory MP Graham Brady, who said in a televised statement early Monday, "The threshold of 15% of the parliamentary party seeking a vote of confidence in the prime minister has been passed."

• Johnson will now face a vote from all of its 359 lawmakers in the House of Commons.
• Brady said the vote will take place in the House of Commons on Monday night and the results will be available soon after.

What they're saying: A Downing Street spokesperson called the vote "a chance to end months of speculation and allow the government to draw a line and move on, delivering on the people's priorities," per Reuters.

• "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."

What's next: If Johnson loses, the Conservative Party will choose a new leader who will also become prime minister.

• Johnson doesn't have an obvious successor, but speculation has centered around Jeremy Hunt, Johnson's former foreign secretary, and Liz Truss, the current foreign secretary.

Editor's note: This article has been updated with new details throughout.