A coronavirus contact tracing app has launched across England and Wales following months of delay and questions about its effectiveness.

The latest version of the app has been in testing among residents on the Isle of Wight and in the London borough of Newham since mid-August, after the first was marred by technical issues and eventually scrapped.

Though the Bluetooth-reliant technology was initially described as the “best possible way to help the NHS” by Transport Secretary Grant Shapps in May, results from other countries already using apps have been mixed.

As the software is voluntary, its success will also depend heavily on how many people choose to download and use it.

It comes at a critical time for the UK, with confirmed cases of Covid-19 on the rise daily.

How will the app work?

The app uses an Apple and Google-developed system, using Bluetooth to keep an anonymous log of people a user has been close to.

It does this by exchanging randomised keys while the Bluetooth signal strength measures proximity.

If someone falls ill, they can tell the app, which will then ping their keys to a central server and in turn send them off to all app users in search of a match.

Should the system determine a person as a close contact, they will be automatically sent a notification and issued with further guidance.

Banbury Cake: The NHS Covid-19 contract tracing app. Picture: PA WireThe NHS Covid-19 contract tracing app. Picture: PA Wire

QR code available on the app

A QR code scanning feature is available, allowing people to check-in to venues they visit and easily share their contact details for human tracing efforts.

What have those behind the app said?

Professor Christophe Fraser, scientific adviser to the Test and Trace Programme, said: “Our Oxford University research team analysis has shown the potential to meaningfully reduce the number of coronavirus cases, hospitalisations and deaths across the population from as little as 15 per cent of the whole population downloading the app and following the guidance to self-isolate.

“This means each one of us can make a difference to help stop the spread of infection, save lives and help protect our loved ones.”