Z-Cars been running for seven years but which some considered 'cosy'. The one character present throughout the entire run (though not in every episode) was Bert Lynch, played by James Ellis (though John Phillips as Det. Chief Supt. Robins would reappear sporadically during the show's run – by the end of the series he had become Chief Constable). Other characters in the early days were Stratford Johns (Inspector Barlow), Frank Windsor (Det. Sgt Watt), Robert Keegan (Sgt Blackitt), Joseph Brady (PC "Jock" Weir) and Brian Blessed ("Fancy" Smith). Also in 1960s episodes as David Graham was Colin Welland, later a screenwriter.
Z-Cars longer format would still work. Thereafter, "Z Cars" was shown in alternating spells of either 2 x 25 minutes episodes or the single 50-minute episode each week over the next sixteen months. This arrangement ended with the showing of the final 2-parter, "Breakage" (Series 6, parts 74 and 75, on 21 and 22 August 1972 respectively), after which the series returned permanently to a regular pattern of one 50-minute episode per week. The "Z-Cars" theme tune was arranged by Fritz Spiegl and his then-wife, composer Bridget Fry, from the traditional Liverpool folk song "Johnny Todd". It was released on record