A contact tracing app that alerts people if they have been close to someone who has tested positive for coronavirus has been suggested by scientists.

It is hoped such technology could significantly slow the rate of transmission and help countries to emerge from lockdowns safely.

A study by the University of Oxford’s Big Data Institute and Nuffield Department of Population Health published in the journal Science proposes an app that uses Bluetooth to keep a log of all other app users a person has been in close proximity with over a few days.

When an individual tests positive for Covid-19, the app can then be used to notify anyone who has been near them anonymously and advise them to go home and self-isolate as a precaution against further spread.

NHSX, the national unit tasked with driving forward a digital transformation of the UK’s health and social care, said it is “looking at whether app-based solutions might be helpful in tracking and managing coronavirus” and has “assembled expertise from inside and outside the organisation to do this as rapidly as possible”.

Professor Christophe Fraser, from Oxford University’s Big Data Institute, said: “We need a mobile contact tracing app to urgently support health services to control coronavirus transmission, target interventions and keep people safe.”

“Our analysis suggests that about half of transmissions occur in the early phase of the infection, before you show any symptoms of infection.

“Our mathematical models also highlight that traditional public health contact tracing approaches provide incomplete data and cannot keep up with the pace of this pandemic.”

However, scientists behind the project say any such app should be opt-in and provide secure data storage and privacy protection.

Development would follow the lead set by Singapore, which has used TraceTogether in its bid to stop the spread of the virus there.

The Irish Government is also reportedly looking into similar technology.

“A contact tracing app can foster good citizenship by alerting people at risk, it can also help ease us out of confinement,” Prof Fraser added.

“If we know we’ve not been in contact with anyone infected we can leave home safely, whilst still protecting our loved ones and avoiding a broader resurgence of coronavirus in our community.”

Professor Keith Neal of the Epidemiology of Infectious Diseases, University of Nottingham, said: “This is a theoretical modelling paper. It does not provide any direct evidence as such that mobile apps could control epidemics without the need for quarantines.

“But it is important in getting the UK to debate what has already been done elsewhere.

“Apps are already in use globally and are probably contributing to management of the epidemic. One concern is that geotracking is a key part in the methodology. If too few people sign up it can only have minimal benefit.

“Uptake would need to be high and too many people may complain about the big brother aspect of the methods and opt out. If used it could always be deleted afterwards from the phone when the epidemic is over. It is well worth trying and apps are already available.”