Businesses across England and Wales are being encouraged to download NHS Test and Trace QR codes to prepare for the launch of an official contact tracing app.

The app, which is currently being trialled on the Isle of Wight and in the London Borough of Newham, will launch on September 24 and will use the codes as part of contact tracing.

Here is a closer look at how the technology will work.

– What are businesses being asked to do?

The Government has asked businesses such as pubs, restaurants, hairdressers and cinemas to download and print out new, official NHS Test and Trace posters, which feature a unique QR code.

As well as businesses in the hospitality sector, universities, hospitals, leisure premises, civic centres and libraries are also being urged to display posters in communal areas such as cafes where people are likely to congregate for more than 15 minutes and in close proximity.

The code, which can be read by the new NHS Covid-19 app, can be scanned by those visiting a venue to quickly check in at that location and therefore help with contact tracing if coronavirus outbreaks are identified.

The codes will be used alongside the app’s ability to detect other smartphones in close proximity.

– Why are posters and QR codes being used?

The Government says the new system will help businesses in England meet the new legal requirement to record the contact details of customers, visitors and staff.

Until now, businesses have individually decided how to collect the contact details of customers, through handwritten registers, online forms or their own QR codes.

However, the Government has argued that the new system can help make the process more fluid by enabling users to quickly check in with their phones rather than using a form or tool specific to a business.

Health Secretary Matt Hancock said the new NHS Test and Trace QR codes will allow the public to “seamlessly” check in at venues and make contact tracing more “simple and easy”.

Businesses currently using their own QR code system are being encouraged to switch to the new NHS system.

– How do the QR codes work?

QR codes work as a visual web link or prompt when recognised and scanned by a mobile device camera.

Within the NHS Covid-19 app, a user will scan the NHS QR code with their phone camera upon entering a venue, which will then prompt the app to automatically log the user’s check-in at that location.

Once this process is complete, a tick will appear on screen alongside the name of the venue to confirm the check-in has been recorded.

The app does not record when someone leaves a venue but automatically checks out the user either at midnight or when the app is used to scan another NHS code.

– How will contact tracing then be done?

If someone with coronavirus is found to have been at the same venue at a similar time to another user, NHS contact tracers will evaluate the risk level based on the venue type and other details of the case.

If the risk level is high enough and an app user needs to self-isolate, they will receive an alert on their phone via the app, which also now features a self-isolation countdown, informing users of how long remains of their self-isolation time.