New details have emerged about the UK government’s controversial contact-tracing app and its progress to date, as supplier VMware revealed that it has completed its involvement and handed over all further work to Swiss software firm Zühlke Engineering.
The UK contact-tracing app’s development has been plagued by missteps and political over-promises since details of its construction were first aired by the government in April 2020, and has fallen behind every scheduled launch date.
In June, the app took a sea-change in its form and is now being developed by Zühlke using a decentralised data-collection model based on Google and Apple’s application programming interface (API) technology, and not the previous much-criticised centralised database structure that the programme originally intended to adopt, and which had been shunned by developers in other countries.
While the UK app became bogged down after a trial in the Isle of Wight that unearthed a number of operational problems, in particular associated with iPhone detection, other countries – most notably Germany and more embarrassingly Northern Ireland and the Republic of Ireland – have steamed on with products of their own.
Despite a succession of government ministers downgrading the importance of the app over recent weeks as deadlines were missed and no release date could be assured, Dido Harding, executive chair of the NHS Test and Trace programme, revealed on 30 July that the app would be launched “shortly”.
On the same day, VMware announced the end of work that had begun in March between its VMware Pivotal Labs division in partnership with NHSX, the technology innovation arm of the NHS.
In an article on its website, VMware offered insight into the genesis of the app’s development and the issues surrounding the centralised and decentralised databases. It said that from the beginning NHSX wanted to pursue a centralised model that was supported by a scalable back-end that could handle millions of records in a more secure and anonymous way.
Computer Weekly has learned that VMware worked with Zühlke from the beginning of its involvement on all aspects of the technology behind the app – contradicting earlier reports that suggested Zuhlke was brought in specifically to work on the decentralised version of the app. Sources close to the project said the plan was always that VMware would spearhead initial development of the app with Zühlke doing testing and assurance, with the Swiss firm taking over fully when ready to do so. Both firms worked on both the centralised and decentralised versions of the app from the inception of each.
Computer Weekly sources also suggested that a Google-Apple compliant version of the app is now ready and could be launched, but the government has so far chosen not to do so.
In the article, VMware said that as early as early March its development team encountered a major testing hurdle regarding a known limitation in Apple’s iOS that caused engineering challenges for contact-tracing app developers, namely detection of phones using Bluetooth when the app was running in background mode.
In early April, VMware delivered a minimum viable product (MVP) based on self-certified symptom reporting, which was the basis of the first trial of the app at a Royal Air Force base in Leeming, North Yorkshire, describing this as a “crucial moment”. As the app went into its subsequent live testing phase in the Isle of Wight, VMware gained availability of API technology from Apple and Google that has formed the basis of decentralised systems, the Google-Apple Exposure Notification (GAEN) infrastructure used in other countries.
The VMware article, written by the firm’s European CTO Joe Baguley, said that it became clear in time that while GAEN incorporated a fix to the background Bluetooth detection issues, it would supply far less granular reporting on location accuracy.
“For example, the NHS app could differentiate between a low-risk situation in which a user passed another individual on the street for a few seconds, while the GAEN approach at that time couldn’t detect between that low-risk situation and if the user hugged someone,” wrote Baguley.
VMware realised that the tipping point for the move to a decentralised system was when the focus of the NHS app switched from notifying people that had come into contact with those reporting officially recognised Covid-19 symptoms, to only those that had received positive tests. At the end of June, in a move planned from the start of the project, VMware handed the development work on the app to the team at Zühlke Engineering.