"Cracker" may be just another in a long line of British crime dramas that were very popular in the early 90's, but "Cracker" stands out as one of the sharpest, wittiest, and most intelligently written of them all. I would say it is even better than "Prime Suspect", which is another personal favourite.
Robbie Coltrane plays his most memorable part as Fitz, a criminal psychologist who has an uncanny ability of getting into the minds of his subjects, and getting under the skin of anyone who knows him. His is an overweight, alcoholic compulsive who gambles, chain smokes, and cheats on his wife. This is balanced out by his brilliance and articulate nature. The series follows him as he helps a group of police inspectors solve various murders, while he copes with the problems in his own life. To call the series riveting is an understatement, it is bloody brilliant.