Yes it does! A policeman is authorised to ask you to identify yourself, and to enquire what you're up to. If you refuse he/she is quite within their rights to take you in for further questioning. If anybody else comes up to you and asks your name and address, and the nature of what you're doing you are perfectly entitled to tell them to **** off. They may then beat you up, of course, but that is illegal..............Oh FFS! Does it really matter.