The top candidates to replace Boris Johnson as U.K. prime minister

How it works: The first stage of the leadership election will begin with the 358 Conservative members of Parliament voting to narrow a list of declared candidates down to two. Then 180,000 or so dues-paying members of the Conservative Party will vote to elect the next leader.

Who could replace Boris Johnson?

Dominic Raab

• The deputy prime minister isn't widely believed to have leadership ambitions, but could assume the role of caretaker prime minister if Johnson is forced to resign immediately rather than wait for the new Conservative leader to be elected.

Rishi Sunak

• As the second-most powerful man in Westminster and the face of the government's popular COVID support programs, Sunak once seemed like the heir apparent — and could still be. But he was fined alongside Johnson over the "partygate" scandal and has seen his popularity fall significantly.

Liz Truss

• The foreign secretary stood by Johnson throughout his scandals while shaping her own hawkish image in confrontations with Moscow over the invasion of Ukraine and Brussels over Brexit. She consistently polls as one of the most popular senior Tories among Conservative Party members.

Jeremy Hunt

• The runner-up to Johnson in the 2019 leadership contest, Hunt is seen as a moderate and is positioning himself as a safe pair of hands to replace the more erratic Johnson. The former health secretary and foreign secretary now chairs Parliament's Health and Social Care Select Committee and is leading an investigation into Johnson's response to COVID.

Sajid Javid

• Javid was the first Cabinet member to abandon Johnson on Tuesday, then went a step further by questioning Johnson's integrity during Prime Minister's Questions. That seemed to signal he was planning another leadership bid after losing to Johnson in 2019.

Ben Wallace

• The defense secretary's profile has grown significantly during the war in Ukraine, during which he has been one of the strongest international proponents of arming the Ukrainians. The Army veteran and Johnson loyalist is highly popular with the Tory base and many of his Westminster colleagues.

Penny Mordaunt

• Currently minister of state of trade policy and formerly the U.K.'s first female defense secretary, Mordaunt is a popular pick to replace Johnson in part because — as a prominent Brexiteer who took a more pragmatic approach while serving in Theresa May's government — some see her as well placed to unite the Tory factions.

Nadhim Zahawi

• A wealthy former businessman whose family fled Iraq under Saddam Hussein when he was 9 years old, Zahawi saw his popularity and profile rise after successfully leading the U.K.'s vaccine rollout. He was elevated to education secretary, then chancellor after Sunak's resignation. But 24 hours later, he joined a delegation of ministers urging Johnson to quit.

Tom Tugendhat

• A British Army veteran who went viral for a speech he delivered during the U.S. and UK's withdrawal from Afghanistan, Tugendhat was the first Conservative to openly declare his interest in running for leadership if Johnson resigned. He has chaired the Foreign Affairs Select Committee since 2017 and is a frequent critic of Johnson.

Suella Braverman

• The attorney general in Johnson's government, Braverman surprised many by declaring her interest in running for leader in a television interview on Wednesday night — without having resigned from the Cabinet herself. Braverman is viewed a hardline Brexiteer who identifies with the right-wing of the Conservative Party.

This is a developing story. Please check back for updates.

Editor's note: This story has been updated to correct that Sajid Javid resigned on Tuesday, not Wednesday.