Line of Duty episode 6 review: Who is the Fourth Man?

Line of Duty review: Its crunch time for AC-12 as time is running out for Ted, Steve and Kate and we have lots of burning questions. Who got shot? Who was found in Spain? And who is the fourth man?

By Alex Fletcher Updated: 26 April 2021 - 4.34pm

The nation breathed a sigh of relief at the start of this week’s episode of Line of Duty as one of AC-12’s finest lived to see another day.

It was Kate Fleming (Vicky McClure), who pulled the trigger (twice - that was her firearms training in action) and shot PC Ryan Pilkington (Gregory Piper).  Farewell rotter Ryan, you truly were the sneakiest, slimiest villain of them all.

But by the end of the episode we were fretting about another one of our heroes. Ted Hastings (Adrian Dunbar) is starting to crumble. With time running out on his career, his team, the search for the Fourth Man ‘H’ and with Pat Carmichael (Anna Maxwell-Martin) breathing down his neck, Ted was feeling the heat this week.

Veering between anger, tears and despair, Ted is a man on the edge.

In an even more perilous spot than Ted is Jo Davidson (Kelly Macdonald). After the shooting of Ryan, Kate and Jo fled the scene and went all Thelma and Louise on us.

Kate used a secret arrangement she has with Steve (Martin Compston) to use his car in a crisis, but Pat Carmichael’s team had secretly put devices on all AC-12 vehicles and were able to track her down quickly.


Davidson took the fall for Ryan’s death, but without 27 locks on her prison cell door she’s going to need eyes in the back of her head to not get punished by the OCG.

With one final extended episode to go, it feels like all six seasons of Line of Duty are slowly getting wrapped up and tied together. It would be a cute call back to season 1, if the final showdown turns out to be between Arnott and Osborne. Osborne evaded justice in season 1 and went on to get promoted - will justice finally be done in season 6? Will Ted get his Fourth Man? And will Kate and Steve finally go for a Balti?

Here are all the burning questions and theories after episode 6…

What did Jo Davidson reveal in her ‘no comment’ interview?

It was close to half an hour and broke the record for the longest ever Line of Duty interview. We’d been waiting for that *beeeeeeeeeeeeeeeeeeep* and showdown between Hastings and Davidson for several weeks, but this interrogation had a very different tone to many we’ve seen before.

Davidson wasn’t attempting to evade justice, defend herself or bring anyone down. A broken and frightened Davidson had one primary concern – staying alive.

After years of working for the OCG, she knows there is nothing Steve or Ted can do to protect her if she spills the beans on who is pulling the strings.

The question mark about Davidson throughout the series had been about how much she was to blame for getting involved in the OCG in the first place.

It turned out to be a heartbreaking story. A daughter of incest, a daughter of the sick and perverted Tommy Hunter and it was Tommy who came knocking when he heard she was doing well at school. Passing exams and with no criminal record, she was the perfect person for the criminal boss to get behind enemy lines, working for the police.

Another little twist was the revelation that Davidson didn't know Hunter was her dad, she always knew him as uncle. The man she believed to be her dad was a copper, a bent one... but she never named him. Who was this man and have we met him before?


Davidson did relent from her ‘no comment’ strategy on a couple of occasions. She took the blame for shooting Ryan Pilkington to protect Kate – much to Carmichael’s annoyance and disbelief.

She also almost cracked when Hastings hammered her for the lowdown on the Fourth Man and when he mentioned the names Thurwell and Osborne. Unfortunately, Carmichael prevented the interview going any deeper down that road.

It’s been a cracking performance from Kelly Macdonald as the guest lead in season 6 and she had big shoes to fill after Stephen Graham’s emotional turn as John Corbett. But she’s managed to pull it off playing a character who is both criminal and victim.

Who was the dead body in Spain?

James Nesbitt must have really wanted to be in Line of Duty. Happy to sign up for just a couple of mug shots and a picture by a boat, the Cold Feet star was killed off before we even met him.

Involved in the Lawrence Christopher cover-up and the abuse scandal at Sands View, Marcus Thurwell was a possible contender to be the Fourth Man.

He’s also been living in Spain – which is where the IP address for the OCG’s computer programme comes from.

It may turn out that Thurwell was sending those messages, but he obviously isn’t the OCG’s top dog. When the Spanish police raided his villa, they were greeted by his fly-covered corpse. Someone had got to him before the police could. A rotten ending for a rotten man.

What are Merchant and Leland up to?

Merchant attacking Farida earlier in season 6

The dreaded duo are back. Merchant (Maria Connolly) and Leland (Claire-Louise Cordwell) are the prison security officers who most memorably poured boiling water over the hands of Lindsay Denton.

Absolute rotters and weasels of the highest order, they were also responsible for breaking the wrists of poor Farida earlier in the series.

In the pockets of the OCG, they are already eyeing up how they can bypass the security cameras and get to Davidson. What horrid plans will they have up their sleeve for their new inmate?

Is Carmichael ‘bent’ or just incredibly annoying?


Brought in by CC Osborne to help speed up the winding down of AC-12, hamper Ted Hastings and keep a close eye on all the unit’s investigations, Carmichael has been a royal pain in the backside.

But is she actually a wrong-un? She’s definitely keen to nail Ted Hastings after she failed to land her man in season 5. But we know that Ted did make some big clangers with Corbett, the OCG and the cash, so she wasn’t totally in the wrong to suspect him.

And although she almost cost Kate her life, she was just following orders by winding down all AC-12’s protection teams.

We know Carmichael is unpleasant and misguided, but we don’t currently think she’s bent and when push comes to shove in the finale, she may even turn out to be ally against Osborne.

Who is the Fourth Man?


Matthew Cottan, Gill Biggeloe and Derek Hilton were the first three. But who is the final ‘H’? Who is the big cheese at the head of the OCG who has been pulling the strings in Line of Duty since the series started?

As Ted kept shouting repeatedly this week, mother of God, who is the fourth man?

With Rohan Sindhwani stepping down, Andrea Wise slipping away from the story and Marcus Thurwell found rotting in Spain, we’re down to one very likely candidate and two rogue outsiders.

The No.1 pick as to be Chief Constable Philip Osborne (Owen Teale). With links to Tommy Hunter back in the Lawrence Christopher cover-up, Osborne has the means and motive to have stepped up after the death of Hunter to take control of the OCG.

We saw in season 1, when he was in charge of a botched anti-terror raid that Osborne was a bad egg, but somehow he’s managed to move on from that incident to climb to the highest office in the force.

His cut backs across anti-corruption and appointment of Pat Carmichael to clean house at AC-12 only further suspicions that the shadowy Osborne is the show’s big bad.


If you’d prefer a more surprising final twist, there are still some fans who believe Ted Hastings isn’t the man of integrity he’d like us to believe.

The moment of anguish in the lift, the cries of frustration over Thurwell’s death, the pensive looks at his old police photos, might be down to his frustration at a forced retirement and his failings. Or perhaps they are because this is a man with the walls closing in on him.

Maybe the comment to Steve about running out of time, wasn’t about cracking the case, it was about being caught out.

At this point in the series, it’s an incredibly far-fetched theory that doesn’t stack up with the character we’ve seen across the six seasons. But we’ve been wrong about Line of Duty before and some fans are convinced that Ted has been bent all along.

What's under the floor at the gun workshop?

As ever, dozy old Chris Lomax was ready to wrap up quickly and head to the pub after a quick search of the workshop where the OCG were making their guns.

Luckily, Steve and Kate arrived in time to point out that two men were never going to be able to clear out all the evidence. The duo suspect the real reason they visted the scene was to cover-up something lurking under the floor.

We got a new bit of Line of Duty jargon to add to our list - GPR (ground penetrating radar) and what lays beneath that floor (Bodies, guns, a giant picture of CC Osbourne with the words 'I did it all' underneath) could prove to be crucial evidence in bringing down the OCG for good. 

Watch Line of Duty season 1-5 on BBC iPlayer.

Watch the season 6 finale on Sunday, May 2nd at 9pm on BBC One.