A crucial update to the Covid-19 app has been hit by chaos after it emerged it would have breached privacy rules set by Apple and Google.
The app was due to be updated last Thursday to improve contact-tracing when pub beer gardens and restaurant terraces reopen in England.
But it was delayed until further notice, as the Mirror first revealed on Thursday.
The update would have allowed users to share all their venue history with NHS Test and Trace with the touch of a button if they tested positive.
That bulk sharing would, in turn, have made it easier to trigger new-style app alerts telling people who were in the same venue at the same time to get a coronavirus test.
The Department of Health and Social Care (DHSC) had claimed this would be done in a "privacy-protecting" way to track down outbreaks more quickly.
But this goes against the rules set by Apple and Google, according to PA Media.
Those rules explicitly state the app’s joint Exposure Notifications System must "not share location data from the user's device with the Public Health Authority, Apple, or Google".
The DHSC confirmed the app update to version 4.8 had been delayed but refused to say why.
"The NHS Covid-19 app is a key tool in our pandemic response," a spokesperson said.
"As venues begin to open up we encourage everyone who can to use the enhanced venue check-in process, which includes advising users to book a test if they attend venues where multiple people have tested positive.
"The deployment of the functionality of the NHS Covid-19 App to enable users to upload their venue history has been delayed.
"This does not impact the functionality of the app and we remain in discussions with our partners to provide beneficial updates to the app which protect the public."
The app update was meant to make it easier to track down people who have sat in the same pub or restaurant as a Covid sufferer, but did not meet them or know who they are.
Currently, people who test positive for Covid are contacted individually by NHS Test and Trace staff, and asked to recall all the venues they have been to in a set amount of time.
Covid sufferers can use the 'venue history' tool in the app to jog their memory as part of this process. But the data on where they have been is not shared in bulk with the app.
This means Test and Trace staff have to ask people to look up their own venue history and recite it verbally, using the app only to jog their memory and nothing more.
Other changes to the app and wider contact-tracing policy went ahead as planned ahead of pub beer gardens reopening today.
Every member of a group must now check in to venues individually, by signing in or scanning a QR code on the app. Previously only a lead member had to sign in.
There are also new posters displaying QR codes for hospitality venues in England.
Apple and Google have been contacted for comment.
