How does this translate into practicalities? What laws do I want Westminster or London Assembly to enact?
The point I was making earlier is that the distinction between dragnet and regular policing is eroding, as this technology becomes widespread.
Presumably it's ok for police to stand at the station and look out for their man, or ask to look at a store's CCTV. We'll... That kind of thing is becoming mediated by software. Upload your CCTV photo to the app, and it finds matches with your target, or multiple targets, or everyone.