Six weeks ago, Boris Johnson’s top team of scientific advisers came to him with a chilling warning. He had to bring in an immediate two-week national lockdown to prevent the spread of the coronavirus from spiraling out of control, they said, and a failure to do so would likely result in what they called “a very large epidemic with catastrophic consequences.”The warning went largely ignored. Only one of the raft of measures proposed by the advisory group—telling people to work at home if possible—was implemented by the government. Stricter rules were brought in for some virus hotspots in England, but Johnson refused to consider a national lockdown, and even publicly mocked the idea as “the height of absurdity” that would inflict unnecessary “misery” on the nation.But the scientists were right. On Sept. 21, the day they delivered their warning, the United Kingdom reported 5,596 new COVID-19 cases and 29 related deaths. On Friday, 274 people died, and there was a further 24,405 confirmed ...