The UK government denied claims it could ditch its new smartphone app to track the spread of Covid-19 after a pilot scheme faced criticisms from privacy campaigners and tech experts. A pilot started this week in the Isle of Wight, an island with a population of 140,000 off England’s south coast, amid hopes that it could be a key tool to help relieve the lockdown in the UK, which has suffered the world’s second-highest coronavirus death toll of 30,615. MPs had called for extra privacy safeguards before it was rolled out nationally. A campaigning organisation also highlighted apparent flaws with how the new system worked. Talks intensified this week between the UK developers and Apple and Google – which run the main smartphone operating systems – to potentially replace the initial app, which gathers more data for health authorities, the FT reported. It said news of the new app was revealed in an IT contract released earlier this week. Matthew Gould, the head of the technology arm of the UK’s national health service, told MPs this week that the decision not to use the US tech giants was not irreversible. He said authorities would change tack if “it becomes clear that a different approach is a better one”. But the government denied there was any plan to scrap the system that is being tested on the Isle of Wight. "The suggestion we are moving away from a centralised model is without foundation," said a spokesperson for NHSX, the technology arm. "We've been working with Apple and Google throughout the app's development and it's quite right and normal to continue to refine the app." Germany has already switched to a system aligned with the US tech giants after its initial domestically-produced app raised privacy concerns. The apps all allow for people to become swiftly isolated after they’ve come into contact with an infected person, allowing others to continue with their lives. An app – coupled with a vigorous track and trace policy – was used in South Korea, which is seen as an international exemplar in tackling the pandemic. The initial British app – developed with help with the UK’s main cyber security agency - works differently from those favoured by many other countries. Germany has now fallen in line with the US, and Italy supporting a model with Apple and Google which retains data on a users’ phone. The UK government said its bluetooth technology was similar to that used by Australia, Norway and Singapore but privacy campaigners have raised concerns. The UK model sends data in an anonymised form to a central server to assess the information and respond. Privacy International, which tested the app before the pilot, said it only appeared to work when the phone was on and the app was running in the foreground. It did not appear to work for older Android devices, it said. The government said the app had the potential to save thousands of lives with an infection prevented for every one to two people who downloaded it. At the launch of the app, the UK health secretary Matt Hancock: “Coronavirus is one of the greatest challenges our country has ever faced and this app will play a vital role in getting Britain back on her feet.”