Britain’s Keir Starmer could hardly have asked for a better first week as prime minister, from hobnobbing with fellow world leaders to England’s run to the final of the European football championships. But a rebellion brewing within his ruling Labour party over child welfare payments and a prisons overcrowding crisis forcing the early release of offenders means the honeymoon is unlikely to last. Starmer hit the ground running upon entering Downing Street last Friday as Labour returned to power after 14 years following a landslide general election victory over Rishi Sunak’s Conservatives. In hi…