I would have to agree with Flying Monkey on this.
Although there is a general 'public place' exception to the Data Protection Act (DPA), by advertising that you are routinely videotaping those round you and by saying you may publish such footage, then you will probably bring yourself under the provisions of the DPA. If this was the case, you would be required to register with the Information Commissioner, provide contact details to all and sundry, and provide access to any footage upon request.
Is it worth it, I ask?