The UK election winner only becomes prime minister when King Charles III says so

Associated Press

LONDON (AP) — The Labour Party has won Britain’s general election, bringing a new party to power for the first time in 14 years. But Labour leader Keir Starmer didn’t actually become prime minister until a carefully choreographed ceremony on Friday during which King Charles III formally asked him to form a new government. It’s a moment that embodies the fact that technically at least the right to govern in the United Kingdom is still derived from royal authority. That’s centuries after real political power was transferred to elected members of Parliament. The process is swift, if somewhat brutal for departing prime ministers, like Rishi Sunak.