The NHS coronavirus contact tracing app has finally been launched in England and Wales after months of delay and questions about its effectiveness.
The app was trialled first on the Isle of Wight and in the London Borough of Newham and was used to send alerts to users after someone had tested positive.
It 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.
If you show symptoms the app will message other users you have been in contact with
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.
Some 160,000 businesses have already downloaded QR codes for use in their facilities.
However as the software is voluntary, its success will depend heavily on how many people choose to download and use it.
The government had originally tried to develop its own app software before deciding in June that it needed to cooperate with companies which provide the technology powering smartphones to come up with an effective product.
The health and Social Care Secretary Matt Hancock said: “We are at a tipping point in our efforts to control the spread of this virus.
“With infection rates rising we must use every tool at our disposal 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.
“Today’s launch marks an important step forward in our fight against this invisible killer and I urge everyone who can to download and use the app to protect themselves and their loved ones.”
A TV advertising campaign with the slogan “Protect your loved ones. Get the app” is being used to encourage people to install the software.
The UK’s major network operators, including Vodafone, Three, EE and O2, giffgaff, Tesco Mobile, Sky Mobile and Virgin Mobile have all agreed to not charge for using it.
Baroness Dido Harding, executive chair of England’s NHS Test and Trace Programme, said: “We want to make it as easy as possible for everyone to engage with England’s NHS Test and Trace service.
“The NHS COVID-19 app enables the majority of people with a smartphone to find out if they are at risk of having caught the virus and need to self isolate, order a test if they have symptoms, and access the right guidance and advice.
“The features of this app, including QR code check-in at venues, work alongside our traditional contact tracing service and will help us to reach more people quickly in their communities to prevent further spread of the virus.
“This is a welcome step in protecting those around us.”