The UK has announced plans for a large-scale contact tracing programme to help the country exit the coronavirus lockdown, with reports that thousands of people are to be recruited.

Other countries are already running such operations. In some Asian countries, such as South Korea, tracers are able to access credit card transactions, phone GPS data and CCTV in an effort to track down everyone an infected person may have come into contact with.

Meanwhile, places like Germany and the US are interviewing people …