Former Chancellor Rishi Sunak, Defense Minister Ben Wallace and chancellor Nadhim Zahawi are among the favorites for the Tory crown after Mr Johnson stepped down following a series of ministerial resignations.
Elections will be held on Monday for the board of the backbench 1922 Committee, which will then set the rules and timetable for the leadership contest.
Potential contenders are currently assessing whether they have the support to prepare leadership bids.
Tom Tugendhat, chairman of the Commons Foreign Affairs Committee, is the first candidate to throw in his hat, saying he is assembling a “broad coalition” that offers a “clean start”.
Foreign Secretary Liz Truss – who returned early from an international meeting in Indonesia – and Mr Wallace are both said to have significant support.
Other ministers considering a run include Transport Secretary Grant Shapps, Attorney General Suella Braverman and Cabinet Secretary Penny Mordaunt.
Live updates
Davey claims it is ‘ridiculous’ that Johnson will remain in office
Liberal Democrat leader Sir Ed Davey has claimed it is “ridiculous” that Boris Johnson should remain in office while his successor is elected.
He told the BBC he would talk to Labor about calling for a vote of no confidence in Johnson if his party does not remove him immediately.
Sir Ed said Tory MPs who supported Mr Johnson “have a heavy burden to bear”.
PM ‘shocked’ by Shinzo Abe . shooting
Prime Minister Boris Johnson said he was “utterly appalled” by the shooting of former Japanese Prime Minister Shinzo Abe.
Japanese media reported that the 67-year-old suffered heart failure during a campaign speech on Friday after the attack.
The country’s national broadcaster NHK TV said Mr Abe was bleeding and clutching his chest as he collapsed and was rushed to a hospital.
Mr Johnson tweeted: “Utterly shocked and saddened to hear of the despicable attack on Shinzo Abe. My thoughts are with his family and loved ones.”
Good morning
Good morning and welcome to the Evening Standard’s live political coverage.
Westminster and the country are reeling from Boris Johnson’s resignation on Thursday – here’s a quick recap of what happened:
– Boris Johnson announced he would resign, saying he was “giving up the best job in the world”.
– Mr Johnson will remain Prime Minister until there is a successor, expected by the time of the Conservative Party conference in October
– Senior Tories have urged Mr Johnson to quit immediately, fearing staying in place would cause a “summer of chaos”
– Boris and Carrie Johnson are reportedly pushing ahead with plans for a wedding party in Checkers as the prime minister shifts in post to a caretaker in his final days