The Guardian view on an NHS coronavirus app: it must do no harm | Editorial

Smartphones can be used to digitally trace Covid-19. But not if the public don't download an app over privacy fears - or find it won't work on their device

The idea of the NHS tracing app is to enable smartphones to track users and tell them whether they interacted with someone who had Covid-19. Yet this will work only if large proportions of the population download the app. No matter how smart a solution may appear, mass consent is required. That will not be easy. Ministers and officials have failed to address the trade-offs between health and privacy by being ambiguous about the app's safeguards.

Instead of offering cast-iron guarantees about the length of time for which data would be held; who can access it; and the level of anonymity afforded, we have had opacity and obfuscation. It is true that we are dealing with uncertainties. But without absolute clarity about privacy the public is unlikely to take up the app with the appropriate gusto.