The shooting of Charlie Kirk at Utah Valley University should send a chill through every British parent, student, and policymaker. An attack like this does not come out of nowhere. It grows out of a culture in which intimidation, toxic rhetoric, and incitement are allowed to fester on campuses until words spill over into violence. For years, many of us have warned that the atmosphere on university campuses is heading in this direction. Jewish and pro-Israel students in particular have described being shouted down, excluded, harassed, and in some cases physically threatened for expressing their identity or simply mourning Israeli...