Being someone who has attended demonstrations and taken part in pickets I have experienced police brutality first hand. For example, during the miners strike I was kicked on one picket line and on another one the pickets, including women - some with young children in pushchairs - were taunted by the police - this included throwing stones at us - they wanted to provoke a response so they had an excuse to pile in and give us a beating. On that occasion nobody on our side reacted - we continued to picket peacefully.
So, our police have a history of battering demonstrators - it even happened on the Countryside Alliance demo when we had the amazing sight of toffs being battered by police on our tellies. There is no doubt that some police officers enjoy the chance to exercise gratuitous violence with impunity. Why impunity? - because they always get away with it. Hardly surprising when the they get unconditional support from the 'free' press who always brand protesters as violent/anarchist/loony leftist/ terrorist agitators. Clearly the press were looking for a good riot on April the first. If you watch footage of the protests you will see that in many shots there are more photographers than protesters.
The police know that a good ruckus is great PR for them. They can provoke trouble and batter people and then claim that they need more powers, equipment and money to deal with 'public disorder'. Governments, who slavishly support the police and their operational independence, are only too happy to oblige.
So we come to the sad death of Ian Tomlinson who followed in the footsteps of Jean Charles De Menezes and Blair Peach. The Guardian's video footage shows him being batoned and knocked over from behind by a riot policeman as he walked away peacefully. Did this assault contribute to his death from a heart attack several minutes later? No doubt there will be many arguments about that over the coming months.
One thing is certain though, if a demonstrator had assaulted a policeman and he had died a few minutes later from a heart attack, that demonstrator would have been arrested and would now be on a murder charge.