We can't restart Britain's economy until we get coronavirus under control

There is a two-stage optimal strategy for dealing with Covid-19, and it is being implemented in a number of countries around the world. The first stage is a lockdown to stop the spread of the virus, implemented as quickly as possible. A lockdown gives a country time to build up its test, trace and isolate (TTI) infrastructure.

The lockdown needs to continue until three conditions are met. The first is that the number of new cases is very low. The second is that the TTI infrastructure is tested and ready to go. The third is that travellers from overseas are effectively quarantined for two weeks.