Debates over privacy and battery life have rather overwhelmed the primary problem of accuracy in the urgent drive to implement effective large scale contact tracing using BLE (Bluetooth Low Energy) via smartphone. We reported the historic collaboration between Apple and Google over contact tracing two weeks ago and how they were planning to address the other problem – lack of buy-in from users – by embedding the technology in the operating system so that it worked automatically without need to download an app. The question of accuracy of course arose at the outset, with both Google and Apple admitting work needed to be done to improve that beyond the current level that can be almost guaranteed of around five meters,…