The “world-beating” NHS Covid app, downloaded by 19 million people, has systematically failed to send alerts telling people to self-isolate after they came into contact with infected people.
Thousands were not contacted by the Test and Trace app, developed under Baroness (Dido) Harding, because it was set at the wrong sensitivity, the government has admitted.
For a month, the Department of Health and Social Care failed to use software developed to make the app work properly. Users whose “risk score” should have triggered an alert were not contacted. As a result, a government source said, “shockingly low” numbers of users had been sent warnings since the app was released on September 24.
The source added that people who owned Android devices were among the worst