LONDON, United Kingdom (AFP) — A smartphone app developed by Britain’s National Health Service (NHS) could be rolled out within three weeks, its technology chief said on yesterday, despite privacy concerns.

Matthew Gould, head of the state-run service’s digital innovation arm NHSX, said the in-house app — reportedly favoured over similar software developed by Google and Apple — would be trialled in a small area to gauge its effectiveness.

The government last week said the app and a wider testing regime would help to prevent a second wave of infection when stringent restrictions are eventually lifted.

Officials are coming under pressure to ease a national lockdown, which was imposed on March 23 and is due for review on May 7.

Deaths and confirmed cases are on a downward trend but Prime Minister Boris Johnson warned on Monday that a full easing of the restrictions was not imminent.

Gould told a parliamentary committee on science and technology that NHSX was “on course to have the app ready for when it will be needed, for the moment when the country looks to have the tools to come out of lockdown safely”.

The app uses bluetooth technology to log the phones of other people that the user comes into proximity with.

The user can then choose to send data to the app if they begin to show symptoms or test positive for COVID-19. A notification will then be sent to other users who have been in close contact.

If enough people use the app, scientists say it could help to keep the virus reproduction rate low and bring the outbreak under control.

The BBC reported the NHS had decided to develop the software in-house rather than use a similar app in development by Apple and Google.

The NHSX version matches contacts centrally via a computer server rather than the tech giants’ model, which instead matches through individual handsets.

Researchers said that made it easier to track the spread of the virus. Other countries in Europe have favoured Apple and Google’s “decentralised” approach.

“Engineers have met several core challenges for the app to meet public health needs and support detection of contact events sufficiently well,” NHSX told AFP.

The service added that the app runs in the background and would not drain battery life excessively — one of the concerns of phone users.

British civil rights pressure group Liberty has voiced concern the app could become a surveillance tool and the public could be forced into sharing data about their movements.

It warned of “serious long-term threats to our rights and way of life”.

But NHSX maintains the data will only be used for “NHS care, management, evaluation and research” and promised it would comply with data protection, privacy and security safeguards.