Recurring characters in the early years included Detective Chief Inspector Charlie Barlow (Stratford Johns), Detective Sergeant John Watt (Frank Windsor), PC "Fancy" Smith (BRIAN BLESSED), PC Jock Weir (Joseph Brady) and PC Bert Lynch (James Ellis).
In 1967, after a year in hiatus (during which Johns and Windsor moved on to star in the spin-off Softly Softly), Z Cars was relaunched with a new format and an almost completely new cast. The only characters to make the transition were Constables Weir and Lynch; Weir left a few years later, but Lynch remained a regular character to the end.
The title of the series refers to the radio callsigns used by police patrol vehicles in the series.
Z Cars had numerous spin-offs, all featuring Charlie Barlow, and many teaming him with John Watt.
Z Cars provides examples of:
- Back for the Finale: Charlie Barlow returned to the series after years away for the series finale, which also featured guest appearances by several members of the original cast playing new characters.
- Cowboy Cop: "Fancy" Smith.
- Darker and Edgier: Mild by modern standards, but it was viewed as incredibly gritty compared to Dixon of Dock Green. There was particular shocked reaction to a scene in the first episode, which has a cop in a car calling a man in the street over... to ask him if he knows the result of a horse race the cop had put a bet on.
- Domestic Abuse: Once shown as a problem even good coppers are prone to.
- Lead Police Detective: DCI Barlow.
- No Communities Were Harmed: Newtown is Kirkby; the nearby city of Seaport is Liverpool.
- Oop North: Set in the Lancashire/Merseyside area.
- Police Procedural
- Retool: Following a year in hiatus, the series was relaunched in 1967, with a new format and an almost completely new cast.