Warning: this article contains spoilers for the final episode of Line Of Duty season six. We strongly advise that you do not read on unless you are fully up-to-date with the BBC crime drama.

Ever since it was revealed that ‘H’ was four people at the end of series five, Line Of Duty fans have been waiting to find out the identity of the mysterious ‘fourth man’. And on Sunday, after seven tantalising episodes’ worth of car chases, OCG-orchestrated shoot outs and some bumper glass box scenes, that identity was finally revealed.

As you’ll no doubt know by now, the ‘fourth man’ turned out to be none other than Ian Buckells (Nigel Boyle), the superintendent in charge of the Hillside team looking into Gail Vella’s murder, who AC-12 had already nicked earlier on in season six for being ‘bent’ (albeit not for being a notorious criminal mastermind).  

Although, in true Line Of Duty fashion, the finale featured some absolutely brilliant moments, many were (understandably) disappointed that the mysterious figure AC-12 had been pursuing for so long turned out to be such a bumbling, seemingly incompetent character – especially with so many brilliant fan theories suggesting that one of the series’ main characters would be revealed as the suspect.

However, just because we weren’t expecting Buckells to be revealed as ‘H’, doesn’t mean his criminal nature doesn’t make sense. 

Indeed, according to the show’s creator Jed Mercurio, there were hints that the officer was corrupt way back in season one, when he first appeared as the detective inspector appointed SIO in the case of Jackie Laverty’s disappearance after Tony Gates’ relationship with her was revealed. 

“It was really about the heritage of the series, going all the way back to season one, where Dot Cottan says, ‘Oh, can I just have a quick word with Tommy Hunter in the back of the van?’ and Buckells goes, ‘Yeah, alright’,” Mercurio explained, speaking on BBC Sounds’ Obsessed With… Line Of Duty podcast.  

“OK, like, really, is that what you should be doing? Of course not.”

Elsewhere in the interview, Mercurio explained why Buckells’ identity as ‘H’ made sense in light of everything else which had happened during the series.

“It was always really important to me that it was someone who had been in season one, someone who had been there the whole time,” he said.  

“We did introduce some characters late, so Thurwell came in late, we went back to Fairbank, who’d appeared in season three, we had the Chief Constable, who had obviously been there since season one.

“But then I don’t think he would have been a satisfying candidate because he had been absent for so long, it would feel like we’d just brought him back in to pin it on him.”

When you put it like that, the idea that Buckells should be ‘H’ kind of makes sense. 

Still, it would have been fun to see a *little* more drama in the last episode – especially after the final trailer made it seem like it would be an action-packed finale.

Nevertheless, however you feel about the final episode, it’s safe to say that Line Of Duty season six certainly left the series with lots of questions left to answer, so we’ll be keeping our fingers crossed that a season seven will be announced soon.

All six seasons of Line Of Duty are available to watch now on BBC iPlayer

Images: BBC