The Ghost Squad.

The Ghost Squad was a 2005 British crime drama series produced by Company Pictures, for Channel 4. The show was created by Tom Grieves. Inspired by the real life "Ghost Squad" that existed between 1994 and 1998, secretly investigating police corruption, the premise of the series is that the squad continued to operate in secret after officially being shut down. It starred Elaine Cassidy as a police constable recruited into the squad and Jonas Armstrong as her handler. The show was cancelled after a single seven episode series.