Failing to follow Apple and Google’s framework for a coronavirus contact tracing app risks pushback from the tech giants, a cyber security expert has warned.

NHSX, the health service’s digital innovation arm, is working on an app that could help towards the relaxation of lockdown measures, by keeping an anonymous log of every person an individual comes into contact with and alerting them if they test positive.

Apple and Google have joined forces to develop a model, with a decentralised approach at the heart of it – meaning the matching process happens between phones, rather than sending anonymised data to a computer server.

The companies are expected to release the first phase of their efforts soon.

One of the main arguments in favour of their solution has been to protect users’ privacy, but NHSX has decided to take a centralised approach so it can better understand how the virus progresses – though it insists people will have control over the amount of data they share and the app will remain optional.

Professor Alan Woodward, from the Surrey Centre for Cyber Security at the University of Surrey, warned that the UK approach could face some issues.

They (Apple and Google) know that their customer base is global, it's not just the US or the UK or European, it's all over the world, so they want their users to not think that governments can somehow subvert their operating systems to become trackers

“Yes, there may be some pushback, I think – the simple way to put it – because what Apple does not want is somebody building a system that could be used as a tracking system, a generalised tracking system,” he told the PA news agency.

“So, repurposing the technology, later on, for example – never mind now in this emergency of the data collected – but could someone, later on, build technology along the same principles just to use Bluetooth to track people?

“And the whole point was, iOS particularly was built, and Android’s later versions, are built so that you cannot do that.”

He continued: “They (Apple and Google) know that their customer base is global, it’s not just the US or the UK or European, it’s all over the world, so they want their users to not think that governments can somehow subvert their operating systems to become trackers.

“So there is a bit of a danger it might get some pushback.

“And I think, if the UK Government are going to sell this to the public, they have to have those epidemiologists, the public health people, out, front and centre, justifying why they need that data.”

Speaking to the Science and Technology Committee on Tuesday, NHSX chief executive Matthew Gould said the smartphone app designed to help contain the spread of Covid-19 when lockdown measures are eased is “two to three weeks” away from being rolled out, starting with a trial in a “small area” in the coming days.

He also said talks are still being held frequently with Google and Apple.

An NHSX spokesman said: “Engineers have met several core challenges for the app to meet public health needs and support detection of contact events sufficiently well, including when the app is in the background, without excessively affecting battery life.

“This has been achieved using standard Google and Apple published API while adhering to the Bluetooth Low Energy Standard 4.0 and above.”