Control

Joe Robinson is back, and Chief Inspector Frank Vickers' hopes of putting his feet up are dead on arrival. Joe has returned to the Vice Squad with a case in his teeth: a violent pimp named Miles Wilson who needs nailing properly, with evidence that sticks. It is the kind of straightforward target the unit rarely gets, which should make it easy.

It is not. The mother of one of the young prostitutes recognises Vickers, and she knows him from somewhere dark. She makes the threat quietly, the way such threats are always made: put the pimp away yourself, personally, or she tells everyone what the two of them got up to. Vickers' past has finally come to collect, and it has chosen the worst possible week. Neither of them explains what that past involved, and the episode is right not to.

Sean Harris plays Miles Wilson with the unblinking blankness of a man who considers violence a form of administration, which makes him a believable target. But the real fight of the episode is inside the squad. Joe's case stops being about procedure the moment the mother opens her mouth, and every step forward is now a deal with someone's history.

Around them the unit turns over. Tamzin Malleson's Lorraine Johnstone is new to the ranks, Jake Nightingale's Stuart Cole keeps the sergeant's office running, and Annette Bentley's Denise and Sarah Ozeke's Lynsey move through the world the pimp controls. Hutchins and Morgan hold the line, as ever.

Mike Cullen wrote it, Jon East directed. It is a tight, contained hour about how much history weighs on the people doing the policing, and it gives Pigott-Smith the kind of material he has been owed since he arrived. Vickers gets to squirm, and the show is smart enough to make us enjoy it. It is the quiet, crowded hours like this that hold the final series together.