After Boris Johnson resigned as the British Prime Minister on Thursday, Rishi Sunak, who stepped down from his position as finance minister two days earlier, may be the leading candidate. After a slew of resignations from his ministries, UK Prime Minister Boris Johnson announced his resignation. Rishi Sunak is thought to be a candidate to become the future prime minister of the UK. He would become the 78th British Prime Minister and the first man of Indian origin to do so.