Mark Daly spent months working as a policeman in Manchester. His fellow officers were unaware that their colleague was, in fact, an undercover journalist who was trying to discover if racism lurked among their ranks.
The Secret Policeman was screened amid a storm of publicity in October 2003.
Graphic images of police officers engaged in racist behaviour - filmed by undercover reporter Mark Daly - caused a huge public outcry.
The-then Home Secretary, David Blunkett, and senior police chiefs condemned the racism on view.
Daly was then posted to a probationary post in Stockport.
In August of 2003, following a tip-off from an anonymous source, Daly was arrested by police internal affairs officers.