Often compared to the popular British crime series The Sweeney (both projects were produced by Euston Films), Thames Television's began its weekly, 60-minute run on September 17, 1969. In its earliest episodes, the series focused upon an elite group of tough, unsentimental London cops, presided over by Superintendent Eden (Wesley Pithey), Det. Supt. Inman (Fulton Mackay), and Det. Insp. Jordan (Derren Nesbitt). After ending its second season on November 4, 1970, went on a three-year hiatus. When it returned on April 4, 1973, virtually the entire cast had been replaced: Now the activities of the were overseen by Commanders Nichols (Richard Butler) and Fletcher (Frederick Jaeger), and Detective Chief Inspectors Craven (George Sewell), and Haggerty (Patrick Mower).