There is no Martial law in London at the present time (14:17, 09,08,2011) Just extra Police. I should know I live in the UK and most of my friends and family live in London. I know those videos can seem disturbing but those who are familier with English Football hooligan culture (Or should I say violence) will be used to most of those images. Not saying it is right though incase anyone misunderstands where I'm coming from.
Beware of sensationalist websites as they are prone to exaggerating things way out of proportion.