Not sure if someone else has mentioned the following already:
Last Sunday around 9 pm a cyclist was mugged by two other cyclists at the crossing of Tooley Street and Tower Bridge Road.
The two guys punched the cyclist in the face and stole his Ipod. The two black guys just moved away - not in a hurry (the front of it).
Yes he was listing to it, all three bikes stopped by the traffic lights and one of the guys punched him on the face, he lost his balance and the two other just went off with the lights still red! I too listen to music when cycling...
Sorry, but I think that cycling whilst listening to music is very dangerous indeed. You are incredibly vulnerable on a bike. You need your wits about you at all times - far more so than in a car - and that includes paying full attention to all senses, including hearing. Even by a river. Not least because you are a danger to other pavement users.