69. February 1964,  November 1965, March 1967 and February 1969. Ian Hendry (I) (qv)s  subsequent series _"Informer, The" (1966)_ (qv) was actually more  popular at the time. So when the production company (Associated  British Corp, nothing to do with the American ABC) was ordered to be  wound up by July 1968 (due to breach of license on another matter)  It was easy for the new company (Thames TV) to cancel the series.