“Keir Starmer has resigned as UK Prime Minister and Andy Burnham has become his successor”

The claim is partially true but critically incomplete. Starmer has indeed resigned as PM and Labour leader (announced June 22, 2026), but Andy Burnham has NOT become his successor. Burnham is the heavy favorite to win the upcoming Labour leadership election, but the formal process doesn't conclude until September at earliest. Starmer remains as caretaker PM until the election is complete.