If you don't see police, you are on camera as well, especially in London. But yes, automatic face recognition is coming so you will be almost fully tracked from the moment you leave your house.
Not that that isn't something to worry about at some point, but for the moment that's fantasy. Almost all these cameras are privately set up and recorded, and requires manually requesting and retrieving video from who owns them. They are also nearly always poor quality monochrome (see any CCTV featured on news reports). All the computing tech in the world won't help the fact that CCTV is neither centrally controlled or accessible, or of decent quality.