Gameboys

Soho's amusement arcades have always been a front for something, and this episode picks the one with the ugliest secret. The manager, Tommy Bowers, is suspected of recruiting young runaways and putting them to work as rent boys, and the Vice Squad sends Adam Parkes in to get the evidence. Nobody on the squad wants the case, which is usually how they know it matters.

Parkes is new to this world, and it shows in the right way. The teenager Bowers has befriended takes a shine to him, which makes the undercover role deeply uncomfortable, and then the bust goes ahead and Parkes gets mistaken for a punter by his own side. He keeps his nerve, which is the job, and the job keeps getting harder. The comedy of errors stops being funny the moment you remember what the arcade actually is.

But the episode's sharpest move is the rentboy called Joe. He decides the pimp's fate himself, and his sense of justice leads everyone on a merry dance through the back streets. Sean McGinley's Bowers is the oily centre of it, all charm and no bottom, and Kate Dickie's Beverley and Lee Turnbull's Ricky fill in the edges of a trade that runs on young lives.

Mel Raido carries the undercover discomfort well, and the familiar unit turns around him: Hutchins, Robinson, Morgan, Vickers looming, Johnstone and Cole holding the paperwork together. It is the kind of episode where the squad's machinery matters less than the one boy at the centre of it.

Ben Cooper wrote it, Justin Chadwick directed. It is an uncomfortable hour with a few too many close calls to be called routine, and it earns its title. These are boys playing men's games, and the games are rigged. It is not the show's most famous hour, but it is one of its most patient.