Happy slapping is a fad in which an unsuspecting victim is attacked while an accomplice records the assault (commonly with a camera phone or a smartphone). Within the UK, where the term is used much more frequently than in the U.S., it is associated with the ned/chav sub-culture.

Your word of the day is "happy slapping." Apparently Europe has its own sort of irrational moral panic. One of the articles linked here says:

So the first thing to be said about this 'craze sweeping the nation' is that no one can tell even whether it's a craze.

Happy slapping - Wikipedia, the free encyclopedia