British Prime Minister Boris Johnson is facing a confidence vote on Monday following a series of scandals, including a damning official report about COVID-19 lockdown-breaking parties at his official residence.
Johnson has vowed to fight on as leader, but if he loses the confidence vote he will be out of a job, and a contest to replace him will begin.
Below is a summary of some of those who could be in the frame to replace him if he loses:
LIZ TRUSS
The foreign secretary is the darling of the Conservatives' grassroots and is regularly top of the polls of party members carried out by the website Conservative Home.
Truss has a carefully cultivated public image and was photographed in a tank last year, evoking a famous 1986 image of Britain's first female prime minister, Margaret Thatcher, who was also captured in such a pose.
The 46-year-old spent the first two years of Johnson's premiership as international trade secretary, championing Brexit, and last year was appointed as Britain's lead negotiator with the European Union.
Truss said on Monday Johnson has her "100% backing" and she urged colleagues to support him.
JEREMY HUNT
The former foreign secretary, 55, finished second to Johnson in the 2019 leadership contest. He would offer a more serious and less controversial style of leadership after the turmoil of Johnson's premiership.
Over the last two years, Hunt has used his experience as a former health secretary to chair the health select committee and has not been tarnished by having served in the current government.
Earlier this year, he said his ambition to become prime minister "hasn't completely vanished".
RISHI SUNAK
The finance minister was until last year the favourite to succeed Johnson. Sunak was praised for a rescue package for the economy during the coronavirus pandemic, including a jobs retention programme, which prevented mass unemployment, that could cost as much as 410 billion pounds ($514 billion).
But he has faced criticism for not giving enough cost-of-living support to households, his wealthy wife's non-domiciled tax status and a fine he received, along with Johnson, for breaking lockdown rules.
His tax-and-spend budget last year put Britain on course for its biggest tax burden since the 1950s, undermining his claims to favour lower taxes.
Sunak said on Monday he backed Johnson's leadership.
NADHIM ZAHAWI
The current education secretary impressed as vaccines minister when Britain had one of the fastest rollouts of COVID-19 jabs in the world.
Zahawi's personal story as a former refugee from Iraq who came to Britain as a child sets him apart from other Conservative contenders.
He went on to co-found polling company YouGov before entering parliament in 2010. He said last week at some stage it would be a "privilege" to be prime minister.
PENNY MORDAUNT
The former defence minister was sacked by Johnson when he became prime minister after she backed his rival Hunt during the last leadership contest.
Mordaunt was a passionate supporter of leaving the European Union and made national headlines by taking part in now-defunct reality TV diving show.
Currently a junior trade minister, Mordaunt called the lockdown-breaking parties in government "shameful". She said last month that voters wanted to see "professionalism and competence" from the government.
($1 = 0.7971 pounds)
(Reporting by Andrew MacAskill; Editing by Elizabeth Piper and Alex Richardson)
