The project has been hit with delays after No 10 was forced to drop its own custom-made version of the app before later partnering with Google and Apple for the new design.
The government has announced that its NHS contact-tracing app will finally be rolled out in England and Wales on 24 September.
Trials have been taking place in the London borough of Newham, on the Isle of Wight and with NHS volunteer responders to establish the effectiveness of the app.
The Department for Health and Social Care said it is “highly effective when used alongside traditional contact tracing to identify contacts of those who have tested positive for coronavirus”.
Pubs, restaurants, hairdressers, cinemas and other businesses are now being urged to ensure they have NHS QR code posters visible on entry so customers can check in using the app.
Health secretary Matt Hancock described the app’s launch as “a defining moment” and said it will help to contain the virus “at a critical time”.
He said: “We need to use every tool at our disposal to control the spread of the virus including cutting-edge technology.
“The launch of the app later this month across England and Wales is a defining moment and will aid our ability to contain the virus at a critical time.
“QR codes provide an easy and simple way to collect contact details to support the NHS Test and Trace system.
“Hospitality businesses can now download posters for their premises ahead of the launch of the NHS Covid-19 app. This will allow the public to seamlessly check in to venues using the app when it launches.
“It is vital we are using the NHS Test and Trace system to reach as many people as possible to prevent outbreaks and stop this virus in its tracks. This function will make it simple and easy so we can keep this virus under control.”
The app uses bluetooth technology to detect if a user has been close to someone who tested positive for Covid-19.
It also allows people to input their location by scanning bar codes in pubs and restaurants.
Other functions include an alert system if local coronavirus rates increase, a symptom-checking tool and a countdown clock for how long you need to self-isolate.
Wales’s health minister, Vaughan Gething, said the app’s launch is “an important part of the coronavirus response” and that it is sensible for the app to work across the two countries.
He said: “Working on a joint England and Wales basis is the most practical option here, as we know there is a lot of movement across our shared border. It makes sense to use the same app, working in exactly the same way, regardless of which country you’re in.
“The Welsh government has worked closely with the NHS app team to ensure the app is easy to use and gives people the right advice and guidance, tailored to the country they reside in. I strongly encourage people in Wales to download and use the app when it launches.
“The more people who download and use the NHS Covid-19 app, the more it will help us to prevent the spread of Covid-19.”
Previous research has suggested that the tracing app is unlikely to be effective in reducing the spread of coronavirus unless it receives widespread support from the public.
A team of scientists, led by University College London, found such apps would need large-scale uptake by the population and support from other public health control measures to be successful.
The findings, published last month in the journal Lancet Digital Health, were based on a review of data from 15 scientific studies published between January and mid-April this year.
Simon Thompson, managing director of the NHS Covid-19 app, said his team was “incredibly grateful” to all those who participated in the trials.
He added that the government was “now giving businesses the time to prepare their venues ahead of the app becoming available across England and Wales”.
