It rained on and off all day too, making it a little harder to capture hotspot information unless the hotspot was a cafe or bar, or there was one in range of it.
Perhaps five minutes after the photo was taken, Leicester Square was once again bathed in sun light.
One other thing I noticed while walking around: there were people lining up for a movie premier, and the security folks were walking the line asking if anybody had a mobile phone without a camera in it. It looks as though they were asking people to check in their phones if they had cameras. I hope that is just for premiers and not for all movies; if it does become common for all movies it will not come us a huge surprise if people stop going to the cinema.