Ms. Badenoch, 44, whose parents were immigrants from Nigeria, becomes the first Black woman to head a party that has had three other female leaders — Margaret Thatcher, Theresa May and Liz Truss. She succeeds Rishi Sunak, who became the first nonwhite British prime minister after taking over the Tories, Britain’s oldest party, in 2022.

Britain’s Conservative Party has elected Kemi Badenoch as its new leader as it tries to rebound from a crushing election defeat that ended its 14 years in power.