There is little doubt that the occupational self-image of the police is that of “crime-fighters” and that this is not just a distortion of what they do, it is virtually a collective delusion. A mountain of research has indicated that police have little impact on crime rates, are responsible for discovering few crimes and detecting few offenders, do not spend much duty-time on crime-related tasks and so forth (for a review of this literature see Morris and Heal, 1981).
Just to put this in perspective, I was in the same “kettle” where British police killed Ian Tomlinson.
I had my wits about me and was able to leave by civil discussion with an apparently rational officer. Tomlinson was not so lucky. He was some working man, a passer by, who was in the wrong place at the wrong time and died trying to leave the area and go home.