Line of Duty, season 6 episode 4 recap: Talking points and plot twists from the latest episode

*Spoilers follow for Line of Duty season six, episode four*

In the world of Jed Mercurio, things have a habit of escalating quickly.

The fourth episode of Line of Duty’s sixth series is a prime example of this. 

For the first 40 minutes or so, we are treated to slow, methodical build-up. A lengthy interview scene involving the guileless DSI Ian Buckells (Nigel Boyle) opens the episode.

Meanwhile, the investigations into the murder of Gail Vella (Andi Osho) and corruption inside the Hillside Lane police station continue to inch forward at a crawl.

But then, after a break in the case sends DS Steve Arnott (Martin Compston) and co to revisit a figure from the series’ past, the episode explodes into action, as a police convoy is attacked in a high-octane shootout (not for the first time). It’s a faintly ludicrous set-piece, but one that ups the stakes for all involved – this was Line of Duty at its most exhilarating.

Elsewhere, the episode also drops a couple of major bombshells about the future of Hastings and AC-12, before ending on a major cliffhanger.

Here’s a rundown of all the big talking points from Line of Duty season six, episode four….

Buckells unbuckled

Last episode ended with the Hill’s dubious chief, Ian Buckells, being taken into AC-12’s custody, after he was found to have history with the too-convenient witness Deborah Devereux (Kerri McLean). 

Under questioning, Buckells doesn’t break as so much as slowly deflate– his lies about previously encountering Devereux are punctured as AC-12 rifle through his randy text history. They couldn’t find any communication between Buckells and Devereux recently, however, and the dodgy DSI seems convincing enough when he claims that the files found in his police-issue vehicle were planted there by someone.

Whether he’s been set up or not, Buckells hardly seems like the criminal mastermind sort, and his imprisonment brings little closure to the situation. He also suggests that Kate Fleming (Vicky McClure) could have had something to do with recruiting crooked copper Ryan Pilkington (Gregory Piper) into the plod. Is this just a man who’s desperate, looking for anyone to blame, or could he be onto something?

Ian Buckells (Nigel Boyle) continues his fall from grace in this week’s episode (BBC/World Productions)

So long and good luck?

Some of Line of Duty’s twists come out of nowhere; this one, however, I think we could all see coming. Ted Hastings (Adrian Dunbar) has been treading a fine line with the top brass all series, after being at the centre of an internal investigation last series.

Now, it seems, he’s pushed it too far, as he’s informed that he will be made to retire within a month. Not only that, but it looks like AC-12 is facing extinction too, as it is set to be merged with a couple of other departments, with 90 per cent of staff cut.

It may be that Arnott picked the wrong time to backtrack on his plans to leave the unit, as he informs a frustrated Nicola Rogerson (Christina Chong) that he needs more time to wrap up some loose ends.

Kate Fleming (Vicky McClure) and Joanne Davidson (Kelly Macdonald) share a moment of camaraderie (BBC/World Productions/Steffan Hill)

Infighting at the Hill

Once again, we see Fleming’s loyalty called into question, as she tips the newly promoted DSI Jo Davidson (Kelly Macdonald) off to the fact that Pilkington has been spotted by AC-12 surveillance lurking around her while off-duty. We know Davidson and Pilkington are in some sort of cahoots, but Davidson drags the young officer into her office for a staring contest and the news that he will be reassigned to another unit.

Pilkington doesn’t take this kindly and shows up at Davidson’s house with a gun to her head; the next day, she informs Fleming that Pilkington won’t be going anywhere, ominously suggesting that Fleming herself should be careful not to appear too guilty.

Ryan Pilkington (Gregory Piper) doesn’t take kindly to the suggestion he is moving on (BBC/World Productions)

Jonesy, we hardly knew ye

In a moment of inspiration Arnott manages to identify the voice heard talking to Gail Vella on a recording made shortly before her death (a feat some fans of the show managed weeks ago). It belongs to Jimmy Lakewell (Patrick Baladi), the OCG-linked lawyer from series four who defended Roz Huntley (Thandiwe Newton) and her husband.

After visiting Lakewell in prison, Arnott concocts a plan to try and get him to share the details of what he knows about Vella’s death, which involves driving him through the city in an armoured van, offering him witness protection.

Thanks to a tip-off, either from corrupt prison wardens or someone inside AC-12, the police convoy is attacked by the OCG, and officer Ruby “Jonesy” Jones (Sherise Blackman) is shot dead, with Arnott and Lakewell surviving only thanks to Arnott’s sharp shooting.

Four episodes in, and we’ve still not seen a lot of DC Chloe Bishop (Shalom Brune-Franklin), but it was she that first noticed the convoy was under attack, and who seems to take Jonesy’s death the hardest.

Fallout

It’s not exactly clear what Lakewell says to Arnott before the convoy is attacked– his laying-it-on-thick tone during the later interview suggests he may have let something important slip before the vehicle is overturned. But, officially, he’s given them nothing, and returns to prison expecting to have preserved his tight-lipped reputation.

The OCG see it another way, however, and Lakewell is garrotted at the end of the episode, by none other than Lee Banks (Alastair Natkiel), the career criminal locked up in Blackthorn prison since last series. A trembling Buckells, meanwhile, watches on.

It’s not a complete dead end for AC-12, however: a pattern of modified weaponry is starting to tie different shootings back to a single workshop.

Mother of God (or should that be daughter or sister?)

The very end of the episode sees Arnott finally receive the results of the forensic analysis of Farida Jatri’s (Anneika Rose) residence. As expected, Davidson’s fingerprints are all over, tearing holes in her lies about her and Jatri’s relationship.

It’s suggested we’re about to find out a major secret about DCI Joanne Davidson (BBC/World Productions/Steffan Hill)

But more interestingly, Arnott says that her fingerprints share DNA with someone that the unit had encountered before– and that they’re almost certainly a blood relative.

Fans have already theorised that Davidson could be linked to John Corbett, but that’s just one possibility. Judging by Hastings’ reaction, it’s someone significant… but we’ve now got an agonising wait until next week to find out who.

Find the contenders to be revealed as Jo’s relative here.