@dymaxion Cameras don't stop crime, because drunken yobbos who feel like beating each other up (being most of the crime that gets recorded by city centre cameras in particular) neither know nor care whether they're being watched, on account of being, well, drunk.

But what the cameras *do* do is reduce the costs and delays in the criminal justice system, as perps who see themselves on screen plead guilty more often, and a guilty plea is *much* cheaper to process through the courts.

And here is a real contribution to justice from a local incident:

Something happened. A usual suspect with a history of that sort of offence happened to be walking past. So the cops nicked him, 'cos "obviously" he'd done it.

And then the cops viewed the footage, and saw that, indeed, as the supposed perp had said, this time at least he hadn't done anything wrong, he really was just an innocent passer-by. Without the cameras he might well have been prosecuted for something he hadn't done.