Line of Duty series 5, episode 5 review: A winningly tense penultimate episode

We have an hour in which the fuses creator Jed Mercurio lit earlier in the season start to detonate

It’s a red letter day for “H”, the shadowy corrupt copper pulling the strings all these years on Line of Duty (BBC1). Or so it appears to DI Kate Fleming (Vicky McClure) and DS Steve Arnott (Martin Compston). They’ve just turned on their boss, Superintendent Ted Hastings (Adrian Dunbar), and pinned him as the big bad in a winningly tense penultimate episode of Jed Mercurio’s claustrophobia-fortified thriller.

Are “H” and Hastings truly one and the same? It seems that way to Ted’s colleagues as he blunderingly tries to bring to a head the investigation into undercover detective John Corbett and the organised crime group (which Mercurio would very much like us to continue referring to it as an “OCG”). Alas, he succeeds only in putting a noose around his own neck and presenting an easy target for his enemies within the force. Of which, there turns out to be quite a few.

Hastings has placed himself in the firing line by ignoring police protocols and going undercover as “H”. That is incredibly rash and flows from his obsession with tracking down Corbett. Alas, the mission is a lost cause given that the missing copper had his throat clashed by gangster Lisa McQueen (Rochenda Sandall) and her goons.

Corbett’s death came out of the blue in the previous episode. Wisely, Mercurio resists the temptation to go one better this week. The closest to a follow-up bombshell is confirmation that the remains wedged in the gangsters’s fridge indeed belong to missing property developer Jackie Laverty from series one. But, of course, fans with a keen memory will have already twigged that.

Instead, we have an hour in which the fuses Mercurio lit earlier in the season start to detonate. As ever with the writer, the excitement is occasionally at the cost of plausibility. Line of Duty has worked overtime to portray Hastings in a negative light. But now we are clearly supposed to feel for him. That’s despite the fact he only has himself to blame for his current predicament. How foolish, first of all, to override the objections of DI Fleming and charge into the gangster’s nightclub posing as “H”.

McQueen is suspicious but goes along with Hastings assertion that he’s the mastermind on the inside. Armed officers next arrive, seizing both her and Hastings. Ted believes all is proceeding to plan, his arrest part of the ruse to convince McQueen he can be trusted (plus he’s recovered all of the stolen swag from the Eastfield heist). But no – he genuinely is under suspicion and is charged with corruption.

That iffy stash of cash he received as compensation for the Kettlebell investment doesn’t look good in light of the allegations. Worse still, putting him behind bars is the passion project of Patricia Carmichael, a careerist anti-corruption officer to whom we are introduced for the first time. She is portrayed by Anna Maxwell Martin, last seen foundering in a sea of school permission slips in Sharon Horgan’s Motherland but who plays her new character as a steel-trap in human form.

So is noble Superintendent Hastings a Ted man walking? It all depends on how clever Mercurio is feeling in next week’s denouement. It isn’t unthinkable that he will string the story out for another series and thus throw Hastings in the clink for the foreseeable future.

Yet it’s also plausible that Fleming and Arnott see the error of their rush to judgement and try to clear Ted’s name. The pressure is clearly getting to them, Fleming snapping at her husband and Arnott flopping in the sack with on-off love interest Sam Railston (Aiysha Hart).

If they do charge to Ted’s side, they will face a formidable adversary in Carmichael, who reduces Hastings to stuttering incoherence setting out the case against him. As he is led away, Hastings gasps that he’s being set up. The same might be said of viewers, with Mercurio blatantly laying the ground for one last shock in the final episode. Whether the climax is enough to justify the season’s often overcooked storyline we will have to wait and see.