A coronavirus contact tracing app will be rolled out across England and Wales on Thursday.

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.

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

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.

A person using the NHS Covid-19 app which is set to be released across England and Wales on Thursday to support the NHS Test and Trace effort. Picture: Scott D'Arcy/PA WireA person using the NHS Covid-19 app which is set to be released across England and Wales on Thursday to support the NHS Test and Trace effort. Picture: Scott D'Arcy/PA Wire

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.

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.

The NHS Covid-19 app on a mobile phone. Picture: Scott D'Arcy/PA WireThe NHS Covid-19 app on a mobile phone. Picture: Scott D'Arcy/PA Wire

How to download and use the NHS Covid-19 App

1. Download the app

Users can download the NHS Covid-19 app from Apple’s App Store on iOS or Google’s Play Store for Android devices.

Search ‘NHS Covid-19’.

A person using the NHS Covid-19 app which is set to be released across England and Wales on Thursday to support the NHS Test and Trace effort. Picture: Scott D'Arcy/PA WireA person using the NHS Covid-19 app which is set to be released across England and Wales on Thursday to support the NHS Test and Trace effort. Picture: Scott D'Arcy/PA Wire

2. Set-up

Users will be met with details about what the app does and a privacy notice first.

The app will then ask for permission to use Bluetooth to carry out automatic contact tracing, as well as the ability to receive notifications, should someone you have been near report symptoms or have a positive test returned.

Prompts will appear on-screen asking people to allow the app to access these features.

Next, you will need to provide the first part of your postcode, which is used to show the risk level in your local area.

3. Interface

The main screen will pulse green to show that the app is active.

Along the top you can see the risk level in your local area.

Below there are a series of options to choose from, including venue check-in and report symptoms.

4. Features

- Venue check-in

This lets people scan a QR code rather than manually providing contact tracing details.

Elsewhere, users can tap ‘About’ at the top of the main screen to see a list of the places they have checked in. There is also the option to delete all data here.

- Report symptoms

Here people can tap the symptoms they have and indicate when these started appearing.

It will then advise you to isolate and a countdown will commence based on the date provided.

A button at the bottom directs people to the Government website where they can then book a test. The results will be sent in the usual way via email or text message, but also within the app.

After doing this, the green pulsing on the home screen of the app will change to red and show you how many days of isolation you have left.