http://www.miscarriageofjustice.org/

Contrary to popular belief, wrongful convictions are not occasional, one off occurrences that come about because of terrible mistakes, or the odd corrupt police officer. People are locked up day in and day out for crimes they did not commit, or crimes that never happened. Witnesses lie in court, defence teams fail to adequately defend their clients, judges “interpret” the law selectively to allow dubious evidence to be presented – the list of causes is very long indeed.