One of the inspirations for Z Cars was when Kennedy Martin “was lying, annoyingly ill, in 1961, monitoring police messages to pass the time and occasionally coming across incidents where it was obvious that the police were not coping. They seemed confused, lost and apparently young and inexperienced”. He took his idea to Elwyn Jones of the BBC Documentary Drama Unit, who decided the new series should be set in the north of England rather than Kennedy Martin’s idea of London.  

The template for the series was the 1958 initiative of  Colonel Sir Eric St Johnston, the Chief Constable of Lancashire, with unmarked “Crime Cars” supplanting beat PCs. Two officers patrolled in vehicles ranging from Zephyrs to Morris Oxfords, and the force intended them as a form of ‘fire brigade’ to rapidly arrive at an incident. 

The BBC first considered using the title Crime Patrol, but they decided on Z Cars after visiting Lancashire’s Information Room and learning of the ‘Z’ call sign prefix. Rose commissioned Fritz Spiegl to rework the Liverpool folk song Johnny Todd for the theme tune.

In late 1961 the crew shot footage in the north-west, the producer informing the press: “The interest and co-operation of the Lancashire County Police has been most rewarding.” A few months later, Sir Eric approached the Corporation to cancel the series, and although he was unsuccessful, the BBC removed a credit which thanked the force for its co-operation. However, this did not affect the viewing figures, which rose to 14 million within a few months.

Each episode consisted of 45 minutes of live studio work, with the shell of a Zephyr placed on rollers in front of a back-projection machine. These sequences were combined with five minutes of pre-filmed material. Blessed still recalls the experience of the red light shining on the Z Cars set and how “I was so very green with the television camera. My hero and mentor was the director Shaun Sutton who gave me so much advice”.