When news emerged last month of a new, far more contagious mutation of coronavirus spreading across Britain there was only one positive straw at which to clutch. There was no evidence, said scientists, that the “Kent” variant was more deadly than the original strain. On Thursday morning, the Prime Minister was shown a paper by the Government’s Nervtag [New and Emerging Respiratory Virus Threats Group] which appeared to destroy even that shred of hope. It considered three studies, which suggest that as well as being remarkably contagious, it is also significantly more fatal - between 30 and 90 per cent more so. Scientists don’t know why. But they think it may be that some of the behaviours which make the variant more easy to transmit, may also make it more lethal. Key among them is the stickiness of the mutation, and the way it gets into cells, and replicates.