Sometimes We Play Dirty Too

The episode title tells you what you're in for, and Prague is where it starts. A British intelligence source dies there in what looks like an accident, and Willie Caine is sent in to find out what really happened. The official version is the first casualty. Meanwhile, back home, Burnside and Mike Wallace are chasing a different sort of trouble: a former government employee from a top secret department is planning to defect to the Soviet Union, taking his Hungarian mistress with him. It's the kind of leak that gets whole departments closed down, and it has the smell of an inside job about it.

The two investigations look unrelated. But they aren't, and the episode takes its time letting the connection surface. Caine works the streets of Prague, piecing a sudden death back together, while Wallace and Burnside dig through the domestic end of the same buried story. The secrets in question were meant to stay in Whitehall's archives, and somebody has been reading them. Caine's dead source and the would-be defector turn out to be two ends of the same rope, and pulling either one starts to unravel the other.

Written by Ian MacKintosh and Arden Winch, directed by Peter Cregeen, first shown on 7 July 1980. Roy Marsden, Ray Lonnen and Michael Cashman anchor it, with Dennis Burgess as 'C'. Bob Sherman, Sue Holderness, Michael Sheard, John Line, Jean Rimmer and Derek Godfrey complete the cast.

The title is doing real work. It isn't a boast; it's a job description, and the episode spends its hour proving it. Even when the crisis looks contained to one city, the danger has multiple entry points, and the men chasing it are already standing in murky water up to their knees. The episode is brisk with it, and the pace suits the material; there's no time to feel clean about anything.