The Third Man

A man swears he had nothing to do with a robbery, and Inspector Jean Darblay does not believe him. The Third Man is built entirely on that doubt, on the painstaking business of unpicking a suspect whose story sits a little too comfortably on him.

The suspect's composure is the problem. He is too calm, too practised, too ready with his answers, and Darblay's refusal to let it pass drives the investigation forward. The episode follows the methodical work of testing his account: the questions asked twice, the details checked against the record, the small cracks that a careful liar leaves behind. She works the case with the full weight of the department around her, from Detective Chief Inspector Jim Logan and Divisional Superintendent Albert Hallam down to Sergeant Joseph Beck, Sergeant George Parrish, PC David Gallagher and Detective Sergeant Bernie Duckworth. Mr. Hamid and Johnny Collins add their versions of events to the pile, and the truth has to be coaxed out of the contradictions.

Ian Kennedy Martin wrote it, Derek Lister directed. Stephanie Turner is Jean Darblay, with Noel Collins as Parrish, David Ellison as Beck, David Hargreaves as Tom, James Grout as Hallam and Tony Caunter as Logan. Gerard Kelly is Gallagher, Lloyd McGuire is Detective Sergeant Bernie Duckworth, Nadim Sawalha is Mr. Hamid and Tony Westrope is Johnny Collins. It aired on 5 December 1981, as the second series drew to a close, and ending the season on an inquiry into doubt and evidence rather than a violent finale said a lot about what the show valued.

The episode is a reminder that instinct is only the beginning of police work. Doubt opens the door, but evidence has to walk through it, and the show takes its time making sure every step is witnessed.

It is satisfying to watch the machinery of the inquiry turn on the small things, the way a lie about a Tuesday afternoon can bring the whole story down. Doubt, handled properly, is a tool.