Plot summary
An operation involving a police informant and a consignment of drugs goes wrong, resulting in the shooting of an informant, Shahid Nafoor ( Pano Masti ), DS Jimmy Valentine ( Robert Glenister ) comes under suspicion. He claims that Nafoor pulled the gun on him, and that in a struggle to disarm him, the gun fired. Brooks, who was part of the operation with Valentine, seems sure that his old friend is telling the truth, and has no questions regarding what happened. However, Devlin, who was watching from the background, doesn't seem so sure that Nafoor made the first move.
Valentine is investigated, and it soon becomes apparent that Nafoor was a drugs runner for Clyde Mason, whom Valentine had a secret deal with. Devlin discovers that Mason had ordered Valentine to shoot Nafoor, after he discovered that Nafoor had been giving the police information on him. He also discovers that Valentine's relationship with Mason began several years ago, after Mason offered Valentine a sum of money to get him off a drugs possession charge. Valentine did so by arranging someone to remove evidence from the evidence store, meaning Mason would walk free on a technicality.
When the case gets to court, however, things become awry. Valentine twists his story, claiming that Brooks was only part of the operation for a specific reason – that he was the person who stole the drugs from the evidence store.
Credits
Adapted from Wikipedia contributors, Law & Order: UK series 2. HTML formatting and reference markers removed.