Investigating corruption is a police matter. But what happens when the corruption comes from inside?
When those entrusted with keeping law and order are those who break the vital code of conduct?
Between the Lines is a powerful and controversial drama which tackled the touchy subject of the police investigating themselves.
Created by John Wilsher and produced by Tony Garnett, the man behind the controversial 1970s series Law and Order, the drama is a tough and uncompromising analysis of that dilemma.
Neil Pearson, perhaps best known for his role as womanising reporter Dave in Drop The Dead Donkey, took the lead role as Det Supt Tony Clark, ambitious head of Mulberry Street police station, who is asked to launch an investigation into his own men.
Recruited by the Complaints Investigations Bureau, he soon finds himself in the uncomfortable and loathesome situation of infiltrating his own station.
The first two series were superb, with great support from Tom Georgeson, Siobhan Redmond and the late Tony Doyle of Ballykissangel fame.
However, by the time a third run was commissioned, Garnett went against his better judgement and obliged with a lacklustre end to the saga.
It was a mistake he wouldn't repeat a few years later for his outstanding series This Life.