Callan (TV series) is run by Colonel Hunter. ("Hunter" is a pseudonym for the current Section Chief, like the C of SIS.) The Section removes those who pose a danger to the "innocent" by persuasion, blackmail, extortion or death. David Callan had been the Section's top operator but he had become too curious about his targets and the rationale for their removal. The Section considered him vulnerable, volatile and dangerous and had laid him off to a dead-end book-keeping job for an ungrateful employer. ABC then commissioned a series of six episodes in 1967. In the first episode Callan rejoins the section in
H. G. Callan H. G. Callan Harold Garnet Callan FRS FRSE (15 March 1917, Maidenhead – 3 November 1993), known as Mick Callan, was an English zoologist and cytologist. He is especially remembered for his work on Lampbrush chromosomes. see Callan was born in Maidenhead in Berkshire the son of Garnet George Callan, a naval architect, and Winifred Edith Brazier, a teacher. He was educated at King's College School in Wimbledon, and then won a place at St John's College at Oxford University graduating with a First Class MA in Zoology in 1938. After initially finding employment at the John Innes Institute in