In a major U-turn, the UK is abandoning the way its current coronavirus tracking app works and is shifting to a model based on the technology provided by Apple and Google.
The move comes the day after the BBC revealed that a former Apple executive, Simon Thompson, was handling the project late.
The Apple-Google design has been promoted as more privacy-focused.
However, it does mean that epidemiologists will have access to less data.
And questions remain that any smartphone-based system based on Bluetooth signals is accurate enough to be useful.
The United Kingdom follows Germany, Italy and Denmark, among others, moving from a so-called "centralized" approach to a "decentralized" one.
The government is expected to confirm the news within an hour.
Despite the change, the interface presented to users will remain the same.
Contact tracking apps are designed to help prevent a second wave of coronaviruses.
They work by registering when two people have been close to each other for a substantial period of time.
If one of the users is subsequently diagnosed with the disease, an alert can be sent to others they have recently been close to, telling them that they should also be tested and / or self-isolated.
The previous UK "centralized" project made contact matches on a remote server.
The Apple-Google model performs the process on the phones themselves, making it more difficult for authorities or potentially hackers to undo the anonymity of the records and use them for other means.
An advantage of the switch is that the NHS Covid-19 app will be able to overcome an iPhone limitation and perform Bluetooth handshake when the software is running in the background.
Another is that it should be easier to make the app compatible with counterparts from other countries, which rely on the same system, including the Republic of Ireland and Germany.
Earlier this week, the European Commission said that France, which had adopted a centralized app, would face challenges in this regard.
More to follow
