A quick link for a lunchtime listen, if you have the time. The first episode of BBC Radio 4′s new series of Law in Action looks at photography in the law: http://www.bbc.co.uk/blogs/radio4/2010/06/photography_and_the_law.html.
As an accompaniment, check out a Radio 4 blog post by its presenter, Joshua Rozenberg, in which he describes his own near encounter with section 44 of the Terrorism Act 2000. When Rozenberg and his producer (and the photographer they were following) were challenged outside a building, they chose to move away rather than risk being searched.
I have managed to reach the age of 60 without troubling the police over any more than a couple of minor motoring matters. Did I really want my name linked to anti-terrorist searches on a police computer somewhere?