Meanwhile, the guy who died yesterday during the G20 protests yesterday has been named as Ian Tomlinson. He seems to have been someone who worked in a newsagent in the City of London. It is unclear whether he was taking part in the protests or was just trying to get home from work. Either way, he found himself caught in a "kettle", this being what the British cops call an area in which they contain protesters, preventing them for leaving sometimes for hours on end. At this stage it is unclear what caused Mr Tomlinson's death.
This "kettle" tactic of the UK cops – on the face of it, it sounds like a form of mass arrest, in that the people held in the "kettle" are prevented from leaving until such time as the police decide to let them. This imprisonment can last for considerable periods of time – yesterday the police held protesters for some seven hours. Following an earlier incident, in which a person so held challenged their imprisonment in the courts, the House of Lords ruled that this form of detention is not illegal under British law.
Ian Tomlinson image source
Three more articles (all from the Guardian):
G20: Questions need to be asked about 'kettling'
G20: The upside of 'kettling'
G20: Did police containment cause more trouble than it prevented?
EDIT: You have probably seen this by now, but the Guardian has obtained footage showing some cops walking up behind Mr Tomlinson and decking him for no obvious reason. See: Ian Tomlinson death: Guardian video reveals police attack on man who died at G20 protest