Callan (1967)

Callan is the title of a British television series set in the murky world of espionage. Originally produced by ABC Weekend Television and later Thames Television, it was aired on the ITV network over four seasons spread out between 1967 and 1972. The series starred Edward Woodward as David Callan, a reluctant professional killer for a shadowy branch of the British Government's intelligence services known as 'the Section'.