Minister downgrades status of UK contact-tracing app from vital to ‘cherry on cake’

Scientists warn of fundamental flaws of Bluetooth technology in proximity measurement function of much-delayed app

The UK government has effectively downgraded the significance and status of the yet-to-be-launched contact-tracing app that is intended to help the country’s fight back against Covid-19.

And in a further blow to the much-delayed project, questions are now being asked about the efficacy of the Bluetooth technology used in the UK app’s fundamental nature.

The app is still officially under development and being trialled on the Isle of Wight, but misgivings over its technical nature have led to a shadow app project with a different technological basis.

On 28 May, the UK government announced the NHS Test and Trace programme, which it said would form a central part of the coronavirus recovery strategy.

The programme comprises four tools to control the virus: test, trace, contain and enable. The trace component involves the situation where someone tests positive for coronavirus. At this point, the NHS Test and Trace service will use dedicated contact-tracing staff, online services and local public health experts to identify any close recent contacts the person has had and alert those most at risk of having the virus who need to self-isolate.

This will be complemented by the contact-tracing app.

At the programme’s launch, the government said the app would be available in “the coming weeks once contact tracing is up and running”. In April, the government announced assurances from NHSX, the NHS’s digital innovation unit, that it would be available in May. When it became apparent that the development timescales were slipping badly, the government revised this to be ready by 1 June, a deadline that has still not been met.

And now, on BBC Radio, in an inadvertent admission of how the app’s prominence in the project is diminishing, UK health minister Edward Argar repeated and tacitly approved the description of the app by NHS Test and Trace programme leader Dido Harding as “the cherry on the cake for this programme”.

Argar was attempting to rebut criticism of the development programme so far, emphasising that the project was seeing the UK government work on the app to “develop it, and work to refine it”.

He added: “It’s the human contact, it’s the tracing that has been done – that is the core part of making this programme work, so the app has the potential in the future to be another step forward. But it isn’t the vital part of it, the vital part of it is this human tracing that we’ve already got running.”

Challenged by the BBC about the statement made by health secretary Matt Hancock in May 2020 that they app was “an incredibly important part of the system”, Argar did not fully support the assertion of his boss as to the app’s importance and instead noted that the app had only “the potential” to achieve this status.

He added: “[Hancock] has also been clear that development is complex…there’s more to do, but I think we have got off to a good start.”

But according to reports by the BBC, and supported by Computer Weekly sources, one of the main reasons the initiative is running behind schedule is that developers are having problems using Bluetooth as a means to estimate distance.

Read more about contact-tracing apps

The UK contract-tracing app works by using Bluetooth to automate the “laborious” process of contact tracing and has the goal of reducing transmission of the virus by alerting people who may have been exposed, so they can take appropriate action. Once installed, the app will use Bluetooth Low Energy to log the distance between a user’s smartphone and other phones nearby that also have the app installed.

The anonymous log of how close users are to others will be stored securely on each user’s phone. If a user becomes unwell with symptoms of Covid-19, they can use the app to inform the NHS, which, subject to sophisticated risk analysis, will trigger an anonymous alert to those app users with whom the user came into significant contact over the previous few days.

Distance will be calculated as a function of the strength of the Bluetooth signal transmitted by other devices. But the BBC is warning that the UK developers are now concerned about the limitations of using Bluetooth, first outlined in a study published by Trinity College Dublin highlighting problems with using received Bluetooth signal strength as a means of estimating distance.

The researchers warned that signal strength could vary “substantially”, depending on: how deeply a handset is placed in a bag; whether the signal has had to pass through a human body to reach the other phone; whether two people are walking side-by-side or one behind the other; whether the devices are indoors rather than outdoors; and whether the smartphone is surrounded by metal objects.

The report highlighted similar issues when Singapore’s TraceTogether app was tested.

Meanwhile, London’s deputy mayor for fire and resilience, Fiona Twycross, expressed concern at a meeting of the London Assembly that high-density housing dwellers, such as those in tower blocks, may not be able to rely on a Bluetooth-based app because of potential false readings.

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