When you’re in the supermarket queue in January 2021 – socially distanced from those around you by two metres – and the phone in your pocket buzzes with a notification from the contact tracing app you installed six months ago, the routine will be familiar. After all, you have been through the process multiple times already.
Someone you crossed paths with last week – the app doesn’t tell you who – has tested positive for coronavirus. It tells you to go home straight away. You must self-isolate until a test has been completed. The test, as with those before