File photo: VCG

The UK will switch to the Apple and Google model for its COVID-19 test-and-trace app, ditching an attempt to develop an app by itself after the homegrown system did not work well enough on Apple's iPhone, the government said.

The test-and-trace program is key to reopening the country but has been dogged by problems. A smartphone app developed by the National Health Service (NHS) was initially expected to be rolled out nationwide in May but did not materialize.

British Health Minister Matt Hancock appeared to blame Apple in part for the pivot, adding that the decentralized Google-Apple system would benefit from work done on the aborted NHS app.

"As it stands, our app won't work because Apple won't change their system, but it can measure distance. And their app can't measure distance well enough, to a standard we are satisfied with," he said at the daily news conference.

"So we've agreed to join forces with Google and Apple, to bring the best bits of both systems together."

Dido Harding, head of the test-and-trace program, has described the app as the "cherry on the cake" of the overall test-and-trace system, playing down its centrality to the program.

But figures for the second week of England's test-and-trace showed that while over 85,000 people who had tested positive for the new coronavirus had been reached in the first two weeks, over 25 percent of positive cases could not be reached.

Officials running the program admitted that the change of tack on the app was unplanned but denied that it was a setback, emphasizing that they did not want to rush out an app that fell short of standards.

But the opposition Labour party said warnings about the homegrown app had not been heeded.

"This is unsurprising and yet another example of where the government's response has been slow and badly managed. It's meant precious time and money wasted," Labour health spokesman Jon Ashworth said.

The UK's adoption of the 'decentralized' approach for its app followed a growing number of European countries including Italy and Switzerland.

But Apple and Google's model has frustrated governments, as they undercut the technology's usefulness by prioritizing user privacy.

The pivot occurred after the NHS app, which was being tested on the Isle of Wight off the southern coast of England, was found to work well on Google's Android operating systems but not on Apple iPhones.