What difference does a metre make? The World Health Organisation recommends that people keep at least 1 metre apart from each other to stop the spread of Covid-19, but different countries have adopted different standards. The US Centers for Disease Control and Prevention recommends staying six feet apart - that’s just short of 2 metres; in the UK, the rule is 2 metres. But all this has a big impact on the way businesses and societies get back to work. Tim Harford investigates the economic costs and conundrums of keeping our distance in a post-lockdown world. How can we avoid infection spreading again, while getting on with life?