That's not necessarily that easy to answer, as (for example) there are different laws relating to CCTV cameras than those relating to, say, press cameramen.
As a general rule (ignoring CCTV for the moment), anyone is free to film who they like, and what they like, as long as they are doing so while in a public place, on their own property or on property where the owner has given permission for photography to take place. (I'm ignoring complicating factors here, such as photography on military bases, indecent photographs of children and voyeurism, as I'm assuming that they're not relevant to your question).
So, for example, it's not illegal to film someone in the street. Nor is it illegal to stand outside someone's house, on a public footpath, and film them through their windows. (Once again, I'm not referring to voyeurism here, which involves filming for the sexual gratification of the cameraman, or of others. That's covered by specific legislation, which I'm assuming isn't relevant here).
Where a photographer or video-maker records images on private property, without the consent of the owner of that property, he/she is still not committing a criminal offence. It's purely a civil matter.
Separate legislation covers CCTV installations though, with the law requiring that they only cover the property that they're used to protect or, in limited cases, public areas associated such properties (such as customers queuing on a public footpath outside a nightclub).