Conservative lawmakers will vote on Wednesday to narrow the field of eight candidates hoping to succeed Boris Johnson as party leader and prime minister, as rival camps trade barbs in an increasingly fractious contest for the leadership.
Three of the 11 initial challengers for the premiership fell away on Tuesday after failing to secure enough support from their colleagues, but the contest remains crowded.
Former finance minister Rishi Sunak is the bookmakers' favorite, and his successor Nadhim Zahawi and foreign minister Liz Truss are among the remaining candidates.
Less familiar figures such as former equalities minister Kemi Badenoch and junior trade minister Penny Mordaunt have won notable support from other senior lawmakers and are popular with the party's membership, who will ultimately decide the winner.
On Wednesday, the remaining candidates will each have to secure 30 votes from the party's 358 Members of Parliament (MPs) to get through to the next round of voting, while the candidate with the fewest backers will be eliminated regardless.
The vote is due between 1230 GMT and 1430 GMT with the result announced afterwards.
Challenges for the winner
Whoever wins will face a daunting in-tray while having to rebuild public trust bruised by a series of scandals involving Johnson, from the breaking of COVID-19 lockdown rules to appointing a lawmaker to government despite having been told of allegations of sexual misconduct.
Britain's economy is facing rocketing inflation, high debt, and low growth, leaving people grappling with the tightest squeeze on their finances in decades. All this is set against the backdrop of an energy crunch exacerbated by the war in Ukraine, which has sent fuel prices soaring.
As the contest intensifies, some of the candidates have offered a series of eye-catching tax cutting pledges, with their supporters turning on their rivals.
Sunak said it was not credible to offer more spending and lower taxes, saying he was offering honesty "not fairy tales."
Culture minister Nadine Dorries, who was fiercely loyal to Johnson and is now backing Truss, has meanwhile accused Sunak's team of "dirty tricks/a stitch up/dark arts" as part of a "Stop Liz" strategy.
Johnson announced last week that he would step down after a torrent of resignations from ministers and open revolt from many Conservative Party lawmakers.
His would-be successors have stressed how they would offer integrity and trustworthiness in contrast, but face questions of their own such as why they backed Johnson for so long, while Sunak, like Johnson, was fined for breaking lockdown rules.
Political opponents say the candidates have been focused only on winning the support of the right-wing of the ruling party by talking about tax cuts and not addressing the cost of living crisis facing the public.