It is striking, looking back, that it was accepted that the level of covid-19 infection in the UK could be controlled by turning on particular non-pharmaceutical interventions at particular times. Indeed such was the belief in this ability to calibrate closely the response that a forward programme of interventions was published with the suggestion that they would be deployed only at the appropriate moment.119 In hindsight it seems a dubious and risky assumption to think that a new, unknown and rampant virus could be regulated in such a precise way. Even more so when—due to the early failure to establish a meaningful testing programme—the UK had very little data on the prevalence and spread of the virus across different settings and different groups of people.