New Judge's answer doesn't tell the whole story. It's the location of the photographer (or, this case, the camera) which is relevant, not that of the people who are being photographed or videoed.
As long as the photographer/camera is located on their own property, on property where they've got permission for photography or in a public place they are free to take pictures and videos of anything or of anyone. (There are obviously a few exceptions, such as images contravening the Official Secrets act, indecent images of children and 'sexual voyeurism' but they're not generally relevant).
You can lawfully capture images of your neighbours in their gardens from the windows of your house, or (while standing in the street) through the windows of their house. Even if you walked into their garden to capture such images you still wouldn't contravene criminal law. (It would be only a civil matter).
There are restrictions applying to CCTV camera on commercial premises but they don't to domestic premises. (The Data Protection Registrar, as he was then called, originally held the opinion that private householders were bound by the same legislation but, following a test case before the courts, the newly-named Information Commissioner now states that they're not).
Chris