LONDON—Former Chancellor Rishi Sunak , who warned that Liz Truss ’ economic plans for Britain were a “fairy tale,” won the contest to succeed her as prime minister on Monday, taking over the world’s sixth-biggest economy at a time of deep financial and political turbulence.
Mr. Sunak will formally enter Downing Street after his only remaining rival for the job, former defense minister Penny Mordaunt , said on Twitter she would drop out of the contest.
“Rishi has my full support,” she wrote.
Mr. Sunak is expected to be formally appointed prime minister by King Charles as soon as Monday afternoon.