LONDON (Reuters) - Branch staff at some of Britain’s biggest banks say rules that require them to store phones in lockers while at work are putting them at undue risk of COVID-19 from colleagues and customers, as they cannot use the country’s tracing app. Lloyds Banking Group, along with rival TSB, are among those advising employees to deactivate the NHS Track & Trace app during office hours, when they are not allowed to keep phones on their person. Some banks ask staff and cashiers to store phones away to prevent leaks of sensitive customer data, although this is not formally required by regulator the Financial Conduct Authority. Under current government guidelines, users of the NHS app are advised to disable bluetooth or pause the app when away from their phones to avoid false notifications. Other companies have told staff to pause the app at work, including pharmaceuticals firm GSK, which said its other safety measures were sufficient, the Guardian newspaper reported. The BTU union, which represents staff working for Lloyds but is not recognised by the bank, said it had been contacted by dozens of staff unable to use the app, which has been downloaded by more than 14 million people. One unnamed Lloyds employee who contacted the BTU said: “I live and work in a high-risk area so I am very concerned at being told that while I’m at work I have to suspend the NHS test and trace app... This defeats the object of track and trace.” Another said they were at risk as they had to conduct face-to-face meetings and due to the “blatant transgression of the social distancing rules by many customers”. “Customers and staff have a right to know if they have come into contact with someone who’s been infected,” said Mark Brown, general secretary of the BTU. Although several European countries have launched Bluetooth-based apps to alert those at risk of catching COVID-19, there is little evidence to date that the technology has significantly curbed infections. Both Lloyds and TSB have advised staff to pause the app’s tracing function while at work, according to internal guidance issued by each lender seen by Reuters. “Colleagues who have downloaded the app to their own smart phone should not use the app while you are at work,” Lloyds told staff, adding it was to stop people receiving false alerts. A NatWest spokesman said the bank encouraged staff to use the app but said they should pause it when they are not with their phone. The bank discourages - though doesn’t ban - the use of personal phones in branches and contact centres. A spokesman for Barclays said the bank had not advised staff to turn off the app. A Department of Health and Social Care spokeswoman said: “We want as many people to download and use the app as possible. It is important to use the NHS Covid-19 app at all times, including while at work, unless in specific scenarios which are clearly set out in our guidance.” A spokeswoman for TSB said: “We’re fully complying with all public health guidance and advising our colleagues in line with best practice.” Lloyds declined to comment. A second employee union, Accord, said rules prohibiting use of personal phones in the workplace were in place to protect employees from security risks. “If customers care about the health and well-being of the bank staff they rely on, they could help by wearing face coverings when visiting bank branches,” Accord’s General Secretary Ged Nichols said.