The Intruder

Frankie Miller has turned up in Hartley, and Inspector Jean Darblay wants to know what he is doing there. The Intruder is built on a knot of secrecy: whatever Frankie is up to, Dick Graydon is covering for him, and the question of why pulls Darblay into a tangle of professional silence and community loyalty.

The episode works in a deliberately claustrophobic register. People who could simply tell each other the truth choose not to, and the show makes that refusal the engine of the hour. Darblay and her colleagues, Sergeant Joseph Beck, Sergeant George Parrish, Detective Chief Inspector Jim Logan and PC Martin Helmshore, have to dig around the edges of the cover-up, and every door they knock on opens onto another person who knows more than they are saying. Betty Graydon, Eddy Butler and Mrs. Dale populate the world of the secret, and the tension comes from the way the truth stays just out of reach.

James Doran wrote it, Sarah Hellings directed. Stephanie Turner is Jean Darblay, with David Ellison as Beck, Noel Collins as Parrish, Tony Caunter as Logan and David Straun as Helmshore. Colin Baker, still a few years from the TARDIS, plays Frankie Miller, Alan Gill is Dick Graydon, Sarah Nash is Betty Graydon, Colin Rix is Eddy Butler and Anne Dyson is Mrs. Dale.

The episode keeps its focus tight on the breach of trust at its centre. There is no need for an overblown confrontation; the betrayal is quiet, and it is all the more effective for being so. Watching established relationships strain under the weight of a secret is its own kind of suspense.

It is a commendable hour, and Colin Baker's presence is a reminder of the show's knack for casting actors on the way up. The intruder, it turns out, is not the only one keeping secrets.