Be Lucky Uncle

Informants are the hidden plumbing of British police work, and when one goes quiet, everything backs up. That is the situation 'Be Lucky Uncle' drops Maggie into: a source has vanished, and the trail of who he talked to last, and what he was about to say, is all anyone has to go on. The title, a piece of advice you might give a nervous man, fits the mood. Everyone has a theory and nobody has a fact. The episode understands that an informant is not a machine; he is a man with a price and a fear.

The writing is shared between Geoff McQueen and Terence Feely, with Gerry Mill directing. McQueen would go on to create The Bill, so he knew his way around this kind of street-level grime. Art Malik, a few years from The Jewel in the Crown, plays Turk, and Ken Campbell, never knowingly understated, plays Lambert. Ben Thomas's Eskimo and Oliver Smith's Charlie Fisher fill the corners, with Tom Cotcher's Banner close behind. The nicknames alone tell you the register. The regulars hold the centre: William Marlowe's Russell, Brian Gwaspari's Croft, Paul Moriarty's Barratt and Kevin O'Shea's Phillips.

The episode is a quiet one, more about listening than chasing. Maggie works the case by reading people, which is where the show always felt most comfortable. The missing man stays mostly off screen, felt through the people who knew him, and that works. There is no car chase and no shootout, just patient door-knocking and sharper questions. But the episode earns the patience it asks for. Maggie's patience here is the point of the exercise.

It went out on 29 October 1982, and it is a reminder that a good informant is worth a dozen anonymous tip-offs. And when they go quiet, the whole machine slows down with them. It is a small story told well, which was always this show's speciality.