This is a review of both Season 1 & 2 of this wonderful British series. Although there is a different story line in each of the seasons, there is some continuity in the important characters: the actors Martin Compston, Adrian Dunbar and Vicki McClure, among others, appear in both seasons as the same characters. The story in each season deals with a conflict within a police department between the regular forces and the internal affairs or "anti-corruption" unit. Thematically, it is concerned with the moral ambiguities that arise when policemen investigate their own. I think this is one of the best British police procedurals that I have seen. The acting and the writing are uniformly excellent, and I hope it comes back for a third season.