Ever since the pandemic struck, a spectre has haunted Boris Johnson: would Britain ever escape from this? His scientific advisers had given him a terrifying vision. Only 7 per cent of the public had caught Covid in the first wave, they said, meaning 93 per cent were still susceptible. So what was to stop his premiership being a never-ending cycle of lockdowns? Now, he has his answer: not one but three vaccines, two with efficacy rates of 95 per cent.