‘Authority’ paranoia over photography in London (and everywhere else)

Huge thanks to Jamie Gordon of Gordon Valiant Photography for sending me a link to this video after he read my previous post.

I think I am going to draw up a letter addressed to "The Police Officer Who Has Just Stopped Me" and always carry a copy with me when photographing.  It will explain how often this happens, cite the relevant laws and be signed by me.  That way the next time it happens I can just hand them a copy.  I'm sure that will grab their attention and get them talking in the station.  Hopefully they'll feel prompted to look up the laws and refresh their memory and the lives of photographers in this region will become easier.

But!  Is Vivary Park public property or private land? What about the seating area in front of Cafe Nero?  I have been photographing in both these locations during this project.  The seating area outside Starbucks is a different case.  All the staff in there know me now and are aware of the project.  If they see me they just smile.  They know that if I'm taking someone's photograph then I will be coming up to the counter in the next few minutes buying a couple of coffees.  They also trust me not to pester people or cause a nuisance to other customers.  Does that passive acknoledgement count as granting permission or is a letter needed?