With less than 24 hours' notice, President Emmanuel Macron announced his plan to plunge the French into a second national lockdown for at least a month. And if everything I hear and read about the UK is to be believed, this country is heading in the same direction. While Boris Johnson will be the person announcing that catastrophic decision, the measures are being dictated by a small group of scientists who, in my view, have repeatedly got things terribly wrong. The Scientific Advisory Group for Emergencies (Sage) has made three incorrect assumptions which have had, and continue to have, disastrous consequences for people's lives and the economy. Firstly, Sage assumes that the vast majority of the population is vulnerable to infection; second, that only 7 per cent of the population has been infected so far; and third, that the virus causing Covid-19 has a mortality rate of about 1 per cent. Multiple research groups in Europe and the US have shown that around 30 per cent of the population was likely already immune to Covid-19 before the virus arrived. Sage has similarly failed to accurately revise down its estimated mortality rate for the virus. Pre-eminent scientists ... have concluded that the mortality rate is closer to 0.2 per cent. That figure means one in 500 people infected die. When applied to the total number of Covid deaths in the UK (around 45,000), this would imply that approximately 22.5million people have been infected. That is 33.5 per cent of our population not Sage's 7 per cent calculation.