Victim

Chief Constable Cullen has a letter on his desk that he would rather not have. Someone is threatening prisoner David Bridie, and the way it is worded suggests the persecution that put Bridie inside is still running, quietly and patiently, from the outside. Bridie, meanwhile, is on a train to London in the care of Evans and Knowles, and their orders are to get him to name the letter writer before anyone else acts on it.

But the danger sits outside the window of a moving carriage. A prisoner who is a target makes an escort a target too, and the two officers riding with him know it. Every face in the compartment has to be weighed, every station stop watched. It is a small, tight set-up, and the episode trusts it. Back in Thamesford, Watt and Hawkins run the case from the home end while Snow and Nesbitt keep the routine moving, and Walter Gotell's Cullen carries the worry well for a man who barely leaves his own office.

Simon Rouse plays Bridie, years before he became the long-serving face of The Bill, and he gives the part a wary, watchful quality that suits a man who knows someone out there wants him dead. Most of the running time Bridie pretends he does not know more than he does, which is a performance in itself. Jean Watt and Sara Hawkins appear in their familiar supportive spots, and the episode finds room for the ordinary business of wives and daughters around the main event.

Elwyn Jones and Arnold Yarrow wrote it, David Sullivan Proudfoot directed. The train journey gives the whole thing a ticking-clock feel, and the ending lands where these things usually land, with the letter writer's identity doing the work the journey promised. There is none of the flash of the bigger cases here, and none is needed.

A threatening letter and a railway trip are modest materials. But the episode turns them into a quiet study of a man under guard and the people responsible for keeping him alive, and it never once strains for effect. The series at this point knew exactly what it was, and this is it.