“This is it, folks,” the outgoing British leader said as he began his seven-minute remarks, in which he called for the Conservative Party to unite behind his successor, Liz Truss, and listed the accomplishments of his government. Among those he chose to highlight: An early choice to deliver weapons to Ukraine after Russia’s invasion that he said may have changed the course of the war, getting “Brexit done,” and the “fastest [coronavirus] vaccine rollout in Europe.”