The End User (1)

Connell keeps tabs on Deakin back home while Clark and Naylor head for Belgium, where a major neo-fascist rally is doubling as a marketplace for illegal arms. Deakin's plan has Clark going undercover as a gun runner, posing as a right-wing arms dealer in the middle of the rally. But the first rule of this show is that undercover work goes wrong. Two Irish arms buyers turn up with their own agendas, and the operation tightens around everyone.

J. C. Wilsher and Dusty Hughes wrote it, Roy Battersby directed, and the episode has the tension of a wire being pulled taut. Clark has to pass as one of the faithful while working the room for the deal, and Naylor is the only one who knows who he really is. The guest cast adds useful menace: Michael Byrne, who menaced Indiana Jones in The Last Crusade, is Mr. Pressman, and David Calder's Leavis and Roger Allam's Peter Adams fill out a world where everyone is selling something. It's the penultimate hour of the series, and it plays like one, every scene loading the finale. Sylvestra Le Touzel's Sarah Teale, Barbara Wilshere's Kate Roberts and Eve Bland's Ellie Hughes are all on the cast list, keeping the wider world of the season in view.

The series has moved a long way from Mulberry Street by now, and it suits it. The rally scenes are properly uncomfortable, the trade in weapons properly grim, and the moral line properly blurred, which is exactly where this show likes to live. It's a setup episode, and a strong one, with the pieces all in place for the finale's collapse. Clark's cover demands he perform the politics of the rally, and the episode doesn't flinch from showing what that costs a man pretending to be something he despises. And the two Irish buyers add a further turn of the screw, their presence threatening to blow the whole operation open at any moment.