The Department for Health and Social Care (DHSC) has launched a new version of the NHS contact tracing app.

Like the first iteration, it will be trialled on the Isle of Wight, as well as with some NHS volunteer responders across England. There are also plans for a pilot in the London Borough of Newham as part of the NHS Test and Trace service.

The new version followed a u-turn by the government, abandoning the centralised approach to collecting data in favour of the decentralised model used by apps developed by Apple and Google.

The supporting system generates a random ID for a device on which the app has been downloaded, followed by personal daily codes and 15-minute codes that can be exchanged by Bluetooth with other app users within range.

If a user reports a positive test for COVID-19, the app will ask for permission to share the daily codes with other users. If agreed, they will be uploaded to a central system hosted on Microsoft Azure cloud servers, which will then send them to other phones to check for any matches. If these are judged ‘high risk’ - within two metres for more than 15 minutes - it will alert the relevant users.

A QR code makes it possible to check into venues to leave a record that the device has been there. The app also has information on Coronavirus symptoms, how to book a test and get results quickly.

DHSC said that personal data does not leave the phone and can be deleted at any time, acting on a permission-only basis to pass on notifications. It does, however, ask for the first four digits of a postcode to alert users if the areas in which they live becomes high risk with the virus.

Health secretary Matt Hancock said: “We’ve worked with tech companies, international partners, privacy and medical experts to develop an app that is simple to use, secure and will help keep the country safe."

Dido Harding, executive chair of the NHS Test and Trace Programme, said: “By launching an app that supports our integrated, localised approach to NHS Test and Trace, anyone with a smartphone will be able to find out if they are at risk of having caught the virus, quickly and easily order a test, and access the right guidance and advice.

“There is no silver bullet when it comes to tackling Coronavirus," she continued, adding: "The app is a great step forward and will complement all of the work we are doing with local areas across the country to reach more people in their communities and work towards our vision of helping more people get back to the most normal life possible at the lowest risk.”

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