Posted: May 26, 2014 2:48 pm
I'm pretty sure they're (Whoever 'they' are! ) using UAVs over South London. On a clear day you can just about spot them circling round. I suspect it's tracking traffic levels.
Lifeboat for the rational mind :D
http://www.rationalskepticism.org/
http://www.rationalskepticism.org/viewtopic.php?p=2009750#p2009750