The public will be urged to download a contact-tracing app for smartphones as the government steps up its battle with the coronavirus.Using bluetooth technology, the app will be used to track COVID-19 infections as lockdown measures ease.The app, which is going into testing on the Isle of Wight tonight, is expected to be rolled out nationwide in the coming weeks.It uses Bluetooth technology to detect nearby phones, showing who the owner of the device has been in close contact with.This will lead to an alert system if one of the user's contacts tests positive for coronavirus.And they will also be able to warn any of their own contacts if they are infected with the virus."The app is exciting," said Matthew Gould, chief executive of NHSX, the