The only recurring actors from the TV series were Edward Woodward as Callan, Russell Hunter as Lonely, and Clifford Rose as Dr Snell.

[3] The Monthly Film Bulletin wrote: "Don Sharp has constructed an unambitious but none the less powerful and convincing little thriller.

The performances are uniformly good, topped by Edward Woodward in the title role, totally at one with the character, and as tight-lipped and uncompromising as ever.

The film is disappointingly slow off the mark, but thanks to Don Sharp's slick direction, the pace eventually begins to pick up, with Edward Woodward excelling as the ex-agent whose ruthless professionalism belies a highly developed conscience.

"[8] Leslie Halliwell said: "Expanded rewrite of the first episode of a long-running TV series, quite fresh and vivid in the circumstances, especially as it comes at the tail end of ten years of similar bouts of blood and thunder.