Answers on a postcard

Architecture enthusiast, Tristan Williams, sent in a few great little Trifles, including this one.

“This strange object can be found just outside of St Paul’s Cathedral in London. When I first saw it I assumed it had arrived from Gotham City and would light up the night sky when Batman’s assistance was required, but obviously there is another reason for it being there. It looks like it might once have held a sign, but perhaps it is also there to prevent access to the corner of the wall. This might be to deter rough sleeping or as an anti urinal device. It may also have some kind of symbolic significance. If anyone has any further suggestions please let me know, it’s driving me mad!”