Z-Cars further spin-off entitled "Second Verdict" in which Barlow and Watt looked into unsolved cases and unsafe convictions. Frank Windsor made a final appearance as Watt in the last episode of "Z-Cars", "Pressure", in September 1978, with Robins (John Phillips), the Detective Chief Superintendent from the original series who had risen to chief constable. Jeremy Kemp, Brian Blessed, Joseph Brady and Colin Welland also appeared, though not as their original characters. "Z-Cars" is incomplete in the archives. The period 1962–65 is reasonably well represented; though with big gaps. With the 1967–71 sixth series, when the programme was shown almost every week,
Theme from Z-Cars of the same song, mentioned in the first of the Para Handy stories, written in Scotland in 1905, which claims that the tune was popular around 30 years earlier. The song also appears in the book "Songs of Belfast" edited by David Hammond, who heard it from a Mrs. Walker of Salisbury Avenue, Belfast, who claimed it dates from around 1900. The "Z-Cars" theme tune was arranged for commercial release by Fritz Spiegl and Bridget Fry, and performed by John Keating and his Orchestra. The single reached #8 in the "Record Retailer" chart in April 1962, and as high as