In an extremely belated and underwhelming response, police in London are warning that they are going to use plastic bullets against rioters. They should have been using real bullets on the first night to kill the firebomb throwers. People who attempt to set others on fire, or who set fire to occupied buildings are attempted murderers. Those observed in the act of such attempted murders should be shot on sight by police, or anyone else. Since the UK has largely disarmed its people, and stripped away the effective right of self-defense, it falls to the police to maintain order and protect the public from these rampaging gangs of human scum. From what I've seen in British news reports, so far they've done a miserable job.
While driving to work yesterday I heard an NPR report on the riots. Their reporter interviewed a woman whose apartment complex was set on fire. She told how while she and her family were fleeing for their lives, their home destroyed, looters were laughing and stealing rugs from a shop on the ground floor of the building. As I've written before about mob violence, these sorts of situations are one of the few times that excessive police force, which would normally be police brutality, is actually called for to restore order. People who act as part of a violent mob or gang, who commit acts of arson, and who think the chaos they've caused is an excuse to appropriate other peoples' property are predatory vermin that needed to be suppressed as quickly as possible with overwhelming force. When a government fails to do so in these situations, its lack of action encourages more vermin to crawl out of their holes and take part in the feeding frenzy.