This is a tricky problem, but I don't think limiting the numbers to public cameras would work. I'm not sure any numerical approach would.
In Atlanta, for instance, the cameras surveilled by the police are 90% privately owned. And this isn't just "with a warrant" or "when a shopkeeper reports a crime and provides tapes", but nonstop, integrated access to their feeds.
Conversely, a lot of the cameras in London may be private, unconnected, and indoors, which I agree is much less worrying. But the Ring of Steel does far more surveillance per-camera-per-capita than any shop camera, since it has unified design meant to maximize how many people are identifiably captured on camera.
In Atlanta, for instance, the cameras surveilled by the police are 90% privately owned. And this isn't just "with a warrant" or "when a shopkeeper reports a crime and provides tapes", but nonstop, integrated access to their feeds.
Conversely, a lot of the cameras in London may be private, unconnected, and indoors, which I agree is much less worrying. But the Ring of Steel does far more surveillance per-camera-per-capita than any shop camera, since it has unified design meant to maximize how many people are identifiably captured on camera.