The NHS COVID-19 app comes as Britain braces for a second wave of infections, with daily cases numbers rising at rates not seen since the peak of the pandemic and a testing system unable to cope with demand in many areas.
The government had said a COVID-19 app would arrive in May, but early trials were dogged by problems, and developers abandoned home-grown technology in favour of Apple and Google’s model in June.
As the delay lengthened, the government downplayed the importance of smartphones in fighting COVID-19, saying that rather than an app being central to the test and trace system, it was “the cherry on the cake”.
Health Secretary Matt Hancock, however, said that with infection rates rising, every tool available must be used to prevent transmission, including the latest technology.
“We have worked extensively with tech companies, international partners, and privacy and medical experts – and learned from the trials – to develop an app that is secure, simple to use and will help keep our country safe,” he said.
The app uses Bluetooth signals to log when a user is in close contact with another user, generally meaning within two metres for 15 minutes or more.
If someone then tests positive for COVID-19, they can choose to share the result anonymously with their close contacts, who will each receive an alert and will have to isolate for 14 days.
The app generates a random ID for each user to protect privacy, and matches cases on the device rather than on a central server, as was the case in the first iteration.
It will also enable users to book a COVID-19 test subject to availability, check symptoms, and register at venues using a QR-type bar code displayed by businesses.
People aged over 16 will be encouraged to download the app by advertisements with the strapline: “Protect your loved ones. Get the app.”