On the twentieth anniversary of the Hillsborough Disaster, the footage of a policeman beating a woman attending a vigil in memory of Ian Tomlinson (see above) is especially resonant. If the police service recaptured any of the public's faith in the years since 1989 - and that's a huge if - then you feel that has now been completely undone. The disgraceful actions of a few Met officers will linger long in the national memory, and skew perceptions of police forces across the country.
Don't get me wrong: I'm a big supporter of the police - they have an extremely difficult job, and there are plenty of professional, dedicated policemen and women out there. But it's clear that the service requires deep reform, and that certain unsavoury aspects need rooting out. This is where the mobile phone footage shot by bystanders can prove so valuable. In this age of citizen journalism, it's becoming less and less likely that the police hierarchy can turn a blind eye to the brutality in its midst. If that encourages justice, and the right sort of change, then it can only be welcomed.