Abduction

A trusted informant tips Regan that a robbery is coming. That is the job, what the Flying Squad does, and it should be a straightforward bit of prevention. But the tip gets him too close. The gang planning the job decide the safest move is to take his daughter, use her as a hostage, and keep him off the scent until the getaway is done.

From there the episode stops being a robbery story and becomes something much more personal. Regan does what any father in his position would do, and what no copper is supposed to do: he goes after her on his own. That puts him against his ex-wife and his own bosses, not to mention DI Ken Knowles, the detective running the kidnap inquiry. The procedural rails come off. Thaw gets to play a man with everything to lose, and he has never been better at that than here.

The kidnap itself is handled with the show's usual bluntness. One phone call changes everything. Regan tears around London breaking every rule in the book, and you are with him the whole way, even when you know his bosses have a point. Carter covers for him where he can, which is what partners do in this show.

It is the season finale, and it earns the slot. Ian Kennedy Martin and Trevor Preston wrote it, Tom Clegg directed. The cast is up to it: Janet Key as Kate Regan, Stuart Wilson's Knowles, Wanda Ventham as Brenda, with Patricia Maynard, Stephanie Turner, Joe Gladwin and Reginald Marsh filling out the world. Haskins is the voice of discipline that Regan ignores, and you can see the sense in what he says, which only makes the situation worse.

The danger feels real because it is aimed at the one thing Regan cannot replace. His usual armour, the sarcasm and the certainty, is useless against this. That was always the trick of the best Sweeney: make the case personal, and the punches land harder.