I’m sure (From one of my old Camera clubs I’ve got an A4 booklet about the laws of photography but it is in my UK house and I’m not!) that you are not allowed to take pictures of people in the street without permission. If you take an innocent but candid shot and say put it on FlickR, you must remove it if a person objects (The chances of them seeing it are pretty slim though eh).
And, I’m also sure there is a seperate set of rules about taking pictures of people in shops. You certainly cannot take photographs in the London Underground (A by-Law) but plenty of people do and put them on the net. Not Policed until a complaint, again.

there is no law saying you cannot take candid photo’s in the street ,

laws on shops vary as it comes down to permission and usualy shopping centres no longer allow it , docklands around canary wharfe are usualy sharp at stopping you too as it is private land where photography is frowned on

it is also vague on cameras pointing from peoples gardens realy as there is a video of two police officers arguing with a house owner that photographed them from his own garden they had to radio someone in charge at the local station to enquire ( the police lost and had to walk off red faced )as again it is not against the law to photograph people in public places

http://youtu.be/6Vj4imfGXYo