The television series Callan seemingly came to an end in May 1972 with the transmission of the final part of a three-part story The Richmond File - A Man Like Me. We saw the anti-hero David Callan walk away from his work for the Section, vowing never to return after the death of a KGB agent. Played by the late, great Edward Woodward, Callan's story appeared at the time to have come to a fitting close. Woodward moved on to other films and television shows including a stint as host on the panel game Whodunnit? and the lead in the much cherished cult classic The Wicker Man (1973) as well as highly regarded theatre work such as The Wolf (1973).
But he and creator/writer James Mitchell returned to Callan in further on-screen iterations. Mitchell adapted and expanded both his original 1967 Armchair Theatre pilot A Magnum for Schneider and the 1969 novelisation 'Red File for Callan' for a cinema version, Callan, in 1974. A tough, well directed thriller, released through EMI in the UK, it reunited Woodward with the television series's cast members Russell Hunter as the much loved smelly informant, Lonely and semi-regular Clifford Rose as Section brainwasher-in-chief, Snell. The major roles of Hunter, boss of the Section, and Toby Meres, a younger agent working alongside Callan, were re-cast with Eric Porter as Hunter and Peter Egan as Meres, replacing both Peter Bowles from the pilot and Anthony Valentine from the series proper. Mitchell also continued Callan's story in a series of novels throughout the 1970s, including Russian Roulette, Death and Bright Water and Smear Job.