Right, got you that's all good then. Possibly the phone app with everyone having B T on would solve transmission in public places like supermarkets.
More or less, but the app isn’t going live yet. It’ll be manual at first - you get symptoms, tested positive then you’ll be called and asked for details of everyone you came into contact with, and they’ll then get called and given the order to isolate. Once the app is live it’ll be more automated (and comprehensive assuming most people download it) as you say.....