Line of Duty season 6, episode 7 recap: All the talking points from the BBC One drama’s season finale

*Contains spoilers for the Line of Duty sixth series finale*

Maybe the real Line of Duty was the friends we made along the way.

The sixth season of Jed Mercurio’s hit BBC One drama came to an unexpectedly restrained and, according to viewers, “disappointing” end tonight (2 May), shifting away from the “Mystery Box” formula and towards a broader commentary on institutional corruption within the police.

Spoilers follow for the Line of Duty season six finale…

That’s not to say that the episode was without its various twists and bombshells – including the revelation that Ian Buckells is seemingly the OCG’s notorious “fourth man”, formerly known as “H”.

It might be an underwhelming conclusion for those hoping for a full-blown Keyser Söze reveal, but it ultimately makes sense – and leaves just enough room for doubt to keep the fan speculation flowing.

There’s a sense of finality to much of the episode, and some unexpectedly happy endings – for Jo Davidson (Kelly Macdonald) and Terry Boyle (Tommy Jessop) in particular.

But others end the episode in limbo, with the very future of AC-12 still up in the air.

Here’s a breakdown of the biggest talking points from Line of Duty season six, episode seven…

The tell-tale box

After digging up the floor at the OCG warehouse, AC-12 discover a strong box, containing evidence to solve a number of unsolved murders, including those of John Corbett and Gail Vella. There were no fingerprints on the knife which killed Vella, but there was a glove with Carl Banks’ DNA inside – enough to finally put the case to bed.

A box is unearthed containing evidence used by the OCG as leverage over its operatives (BBC)

It’s a little neat, perhaps, but explained away plausibly enough: this was the OCG’s blackmail box, containing leverage used to keep people under its control. Whether it’s a satisfying end to the Vella investigation is pretty moot. We’ve known for weeks it was Carl Banks who pulled the trigger. The only question left was who told him to do so.

Saved by the Bill

Watching Line of Duty, you’d be inclined to believe that armed police convoys are among the most dangerous places on Earth. Episode seven sees another one in the firing line, as Davidson is secreted out of prison and transported across the city into an ambush. At least, that’s what’s supposed to happen – but a canny switcheroo from Steve Arnott (Martin Compston) and Kate Fleming (Vicky McClure) saves the day, and lands a couple of OCG arrests.

Steve Arnott (Martin Compston) and Kate Fleming (Vicky McClure) during the Line of Duty finale (BBC/World Productions/Steffan Hill)

With Davidson secure, Fleming tells her she can be entered into witness protection, and that her reports have consistently suggested Davidson was coerced into helping the OCG against her will. That leaves the mystery of her father, the man whom her biological uncle-father convinced her was her dad.

All signs point to Patrick Fairbank (George Costigan) being Davidson’s former father figure, grooming her for the OCG from within the ranks of the police. Approaching him again for questioning, AC-12 get a blustering, befuddled (and rather over-acted) denial from Fairbank, who claims not to remember the details.

Who is the fourth man?

It’s also finally revealed who’s been sending those sinister instructions to Davidson, the same man who’s unable to spell “definitely” correctly: none other than Ian Buckells (Nigel Boyle). Analysis of the spelling in Buckells’ historic police reports, along with a forensic analysis of the incriminating computer, mean the mystery of “H” lands, finally, at Buckells’ feet.

After a long interrogation in which Buckells just repeats “no comment” like a pullstring doll, he finally flips – telling them he has been the key point man for the various OCGs, operating within the police force. Underneath a veneer of bumbling incompetence, Buckells has been getting away with rank corruption.

“I’m the one who’s made total mugs out of you lot,” he gloats, smugly assuming he will be granted witness protection in order to cover up the extent of institutional corruption in the police. However, by pressing him about the involvement of Chief Constable Philip Osborne, Arnott and co manage to squeeze him into a Catch-22, and he ends the episode locked up.

Nigel Boyle as Ian Buckells in Line of Duty season 6, episode 7 (BBC)

It’s a slightly underwhelming reveal – although Buckells’ mix of greed and incompetence is probably truer to life than any more impressive mastermind the show could’ve concocted.

As for James Nesbitt’s mysterious Marcus Thurwell, it seems Mercurio pulled one over on us. The bodies found in the house at the end of episode six were confirmed to be Thurwell and his wife; he was a red (now dead) herring. Unless the Spanish authorities were feeding AC-12 false information (it’s not like you ever see the face of his cadaver), Nesbitt’s not coming back – and can chalk this one up as the easiest day’s work he’s ever had in his life.

Ted Hastings absolved

The star of the episode was undoubtedly Ted Hastings (Adrian Dunbar), who enjoys the closest thing to a full character arc we’ve seen in this plot-heavy season of television. While fans have long hypothesised that Hastings has been crooked all along, the sixth series finale offered a comprehensive refutation of the idea, re-establishing him as AC-12’s bastion of virtue.

Adrian Dunbar as Ted Hastings in Line of Duty (BBC)

When Arnott and Kate Fleming (Vicky McClure) confront him, Hastings opens up about the money given to Steph Corbett, and about the apparent tip-off to Lee Banks that cost John Corbett his life. Dunbar really strains for the Bafta in this scene, remorse and guilt pumping through Hastings’ veins.

His rant to Patricia Carmichael (Anna Maxwell Martin) at the end of the episode is an interesting scene, and forms the crux of what Line of Duty is trying to say with its “H” twist. Corruption like this is never a one-off, and is allowed to thrive only because of institutional failings throughout the police as a whole. Absolving himself, he then confesses to his transgressions, leaving the ball in Carmichael’s court with regard to punishment. As he descends the lift with Arnott and Fleming, his fate is still up in the air – but his head is held high.

Arnott faces the music

It’s been the ticking time bomb at the heart of Steve Arnott’s arc this season: his struggles with prescription painkiller use. We saw last episode that he was facing disciplinary action for avoiding a meeting with occupational health following the results of his drugs test; finally, reluctantly, he faces his demons.

Steve Arnott (Martin Compston) in Line of Duty, episode seven (BBC)

And the result isn’t so bad. Like Hastings, Arnott is still very much in limbo as the season ends, but is now getting professional help for his problem. His admission to Hastings – and his supervisor’s wonderfully sympathetic, almost fatherly response – is the sweetest note in an episode that had a surprising number of them. The other emotional lynchpin of this episode, and of the season as a whole, is Arnott’s friendship with Fleming, and the finale ended with them as tight as ever.

Is this the end?

On the one hand, there was a real sense of finality to this episode: for Davidson, for Hastings, for the Gail Vella investigation. With the mystery of “H” (mostly) put to bed, and six seasons now behind it, Line of Duty must be approaching the end of its natural lifespan.

However, there are still threads that were left answered, and the episode’s final shot – stating that “AC-12’s powers to curb wrongdoing in public office have never been weaker” – would be a particularly downbeat way for the series to conclude. My money’s on another go-around, but it might have a very different look to what’s come before….