For the past seven weeks, dedicated Line Of Duty fans have spent every single waking moment of their lives trying to figure out one thing: who the hell is H? (Well, that and what all those bloody police acronyms mean, we guess). But, despite all the brilliantly complicated fan theories that have graced the internet, it seems the simplest solution to the thrilling multi-season storyline was, in fact, the correct one.

That’s right, folks; Sunday night’s big finale revealed that it was only bloody Ian Buckells (Nigel Boyle), aka the superintendent in charge of the Hillside Lane murder squad. 

It was the sort of “huh” conclusion that left many viewers feeling more deflated than an old party balloon (you know, the really sad and wrinkly one you find behind the sofa a whopping six months after your birthday? That one). Particularly as they’d poured so much time and energy into finding an abundance of “clues” to support their conspiracy that Kate Fleming (Vicky McClure) was H all along.

But here’s the thing, though; the evidence was there, if only we’d been looking for it in the right place. After all, it was Buckells who messed up the paperwork in the season premiere, giving the OCG an unobserved window in which to frame Terry Boyle (Tommy Jessop) and shove him unceremoniously into Ross Turner/Carl Banks’ flat. He, too, was the one who coaxed false testimony out of Deborah Devereux (Kerri McLean) to tie that same unlucky Terry to the murder of Gail Vella (Andi Osho).

Buckells also personally recommended that Jo Davidson (Kelly Macdonald) be placed in charge of the Vella murder case, despite having never worked with her, which is… well, it’s more than a bit dodgy, considering what we know about her now. And let’s not forget that Ryan ‘Bent Copper’ Pilkington (Gregory Piper) was transferred to Hillside Lane at the express request of Buckells, too.

So, why did none of us – not AC-12, not viewers watching at home – suspect him? Well, it’s not just because the series paid him so little attention (honestly, this writer had forgotten Buckells was even an H candidate until tonight); it’s also because he’s always seemed like an insufferable idiot. The kind of person who “fails upwards,” as Ted Hastings (Adrian Dunbar) puts it so spectacularly. As such, his corruption was mistaken for incompetence, and all eyes were elsewhere; indeed, Jo even tried to frame the “blundering fool” as H at one point.

It “definately” seems fitting, then, that Buckells’ downfall came as a result of his sloppy spelling. And that his motive for becoming the so-called ‘Fourth Man’ was such an underwhelming one; plain simple greed.

“I’m the one who’s made total mugs out of you lot,” Buckells informed a flabbergasted Hastings, Steve Arnott (Martin Compston), and Kate Fleming (Vicky McClure). Then, he pointed out the reality of the situation; Patricia Carmichael (Anna Maxwell Martin) hadn’t deigned to sit in on his interview, because she didn’t want her name attached to the controversial case.

“Institutionalised corruption doesn’t exist officially,” he added, with a smug smile. “So I’ll take immunity and witness protection.”

Now, we know that Buckells – to put it bluntly – fucked up a bit here (as Hastings informed him in no uncertain terms, “no one makes mugs out of AC-12”); by the end of the episode, he was stuck in a cell for vulnerable prisoners at a maximum security facility.

However, he was bang on the money, too; top police officers did not want the corruption within their ranks exposed to the public – so they buried it. And they buried it deep. Indeed, Chief Constable Philip Osborne (Owen Teale) delivered a speech pretty much to this effect, in which he claimed that the public doesn’t want to know about every misdemeanour conducted by officers of the law; they just want them to do their jobs.

And herein lies the message of Line Of Duty season six. Because, while we all had H pegged as the show’s true evil, it seems showrunner Jed Mercurio has something far bigger to say about the evils that can come hand-in-hand with institutional authorities.

“It’s not possible [that Line Of Duty has been inspired by real life], because police corruption doesn’t exist in the real world,” he told The Guardian recently, sarcasm dripping from every word.

“That’s what [Metropolitan police commissioner] Cressida Dick says, so who am I to argue?”

Based on the LOD season six finale, it seems as if Mercurio has a great deal to say on this matter. Because, to him, the villain is not necessarily the person who starts the metaphorical fire. Rather, it’s the person who finds themself in a position of power, and chooses not to put the fire out – or even the person who chooses to sit before that fire, happily warming their hands.

Come the end of the episode, Osborne is very much still in power, despite his links to Buckells and Marcus Thurwell (James Nesbitt). Carmichael, meanwhile, has happily promoted all of her pals to senior ranking roles at AC-12. It seems unlikely that Buckells’ crimes, let alone his trial, will ever become public knowledge. And Hastings’ role in the death of John Corbett, too, has apparently been brushed under the carpet, despite him delivering an impassioned statement to Carmichael and a plea for her to use it if she cares about “truth and accountability.”

Finally, and perhaps most tragically of all, we learn that the unsolved Lawrence Christopher case (inspired by the real life murders of Stephen Lawrence in 1993 and Christopher Alder in 1998) remains closed, despite a wealth of new evidence unearthed by Kate and Steve. Because, much like every other fictionalised instance of corruption in the Met Police, it has been buried by those in charge.

It all calls to mind that iconic quote from the late Sir Terry Pratchett: “It’s much better to imagine men in some smoky room somewhere, made mad and cynical by privilege and power, plotting over brandy. You had to cling to this sort of image, because if you didn’t then you might have to face the fact that bad things happened because ordinary people, the kind who brushed the dog and told the children bedtime stories, were capable of then going out and doing horrible things to other ordinary people. 

“It was so much easier to blame it on Them. It was bleakly depressing to think that They were Us. If it was Them, then nothing was anyone’s fault.”

Essentially, if we go looking for monsters – for the H’s of the world – then we’ll never find them. Because real evil, the kind that exists in the world that Line Of Duty is inspired by, is usually far more sedate, and organised, and ordinary. It comes with polite smiles, and paperclips, and neatly-arranged files. And it stems from a belief that hiding the truth is “the right thing to do.”

That’s why we need whistle-blowers, and activists, and changemakers. And so, speaking of which, what of Kate, Ted, and Steve, aka our three stalwart heroes? 

Well, the last we see of them, they’re plunging downwards in a glass elevator, anxious looks on their faces – and fairly, too; after all, they are the “weakest” they have ever been.

Fingers crossed, then, that they are able to rise from the ashes (not to mention win back the hearts of disappointed viewers) and fight the good fight for the truth once again. Because, without them, who the hell will?

Line Of Duty season six is available to view on BBC iPlayer.

Images: BBC