|Series 5, Episode 1|
|Air date||7 July 2008|
|Written by||Douglas Watkinson & Roy Mitchell|
|Directed by||Martyn Friend|
The trial of Ricky Hanson begins, and the members of UCOS are scheduled to appear as witnesses. Hanson is the man who killed Jack Halford's wife, but he's on trial for attempting to murder Jack. Hanson's barrister is clearly out to discredit each of them individually, bringing up past demons and driving one of them to the edge. While at the courthouse, they are asked by an acquaintance of Jack's, Sam Tallis, to look into the death of Ralph Wheeler, who was killed and left his fortune to a prostitute named Carrie Soper. As they look into the case, they find several possible suspects, including a solicitor, a doctor, and someone with a lengthy criminal record. In the end, the case revolves around a car accident and an organ racket. Back in court, Jack seeks justice for his wife and Gerry's past comes back to haunt him when his daughter Emily discovers the truth about her paternity.
According to reviews and ratings on IMDb and TV.com, Spare Parts has received Mixed to Positive reception from critics and fans with many reviews praising the courtroom scenes and the emotive ending.
This episode served as the first appearance of the fourth, and current, UCOS Headquarters.