(Thorley Walters), a member of the British Foreign Office and the Secret Intelligence Service, who became involved when there was a political or intelligence aspect to an investigation. Production The first series was shot primarily on videotape, with only location footage being shot on film. The second series featured more use on film: the opening episode, "The Wheeler Dealers", was shot entirely on film and the final episode, "Marriages, Deaths and Births", was shot entirely on film except for the title sequence and a small number of scenes at the police station. From the third series onwards the entire production moved to 16mm film. The first series was scripted by a number of writers, and only Leslie Duxbury wrote more than one episode. He contributed one further script, for the second series. During series two the series creator, Murray Smith, became the principal writer, and he wrote all but six of the remaining twenty-five episodes. Cast Don Henderson as DS/DCI George Bulman Dennis Blanch as DC/DS Derek Willis Frances Tomelty as WDC Linda Doran (Series 1—2) John Ronane as DS/DI David Singer (Series 1—4) David Hargreaves as DCI Rainbow (Series 1—2) Fiona Mollison as WDC Vanessa Bennett (Series 2—5) Mark McManus as DCS Jack Lambie (Series 3—5) Bruce Bould as DI Tom Casey (Series 3) Thorley Walters as William Dugdale (Series 3—5) Episodes Series 1 (1978) Series 2 (1979) Series 3 (1980) Series 4 (1981) Series 5 (1982) References External links ITV television dramas British thriller television series Television shows based on British novels British television spin-offs 1978 British television series debuts 1982 British television series endings 1970s British drama television series 1980s British drama television series British detective television series Television series by ITV Studios English-language television shows Television shows produced by Granada Television