LONDON — Keir Starmer said Monday the U.K. will ban social media for under-16s. Livestreaming and tools which allow users to communicate with strangers will also be blocked, and restricted by default for 17-year-olds, the U.K. prime minister said. Starmer told a Downing Street press conference “a full ban is the right choice,” adding he is not “prepared to compromise on the safety and happiness of our children.” Proposals for the ban will be brought to U.K. lawmakers before Christmas, with the