In between meetings yesterday I took a long walk along the south bank of the Thames, stopping off at the Tate Modern shop to browse through the photography books (and add a couple of them to my Amazon wish list).  As I left the building to continue my walk, I caught the eye of a security guard who didn't look too happy, possibly because he was working inside on such a sunny afternoon.  He didn't appear to be very happy that I was taking this photograph either, but I shot him anyway.