Line of Duty finale explained: Who was the Fourth Man? (2023)

“We've stopped standing up for accountability and stopped caring about truth and integrity.”

The finale of Line of Duty season 6 may have been frustrating for some viewers who were hoping for justice to be served out to every bent copper from CC Osborne down, but writer Jed Mercurio quite rightly opted for anger and frustration in this finale rather than celebrations and happy endings.

Ted Hastings’ (Adrian Dunbar) closing speech was filled with fury as he lambasted every policeman and official who had turned a blind eye and looked the other way.

The Fourth Man didn’t turn out to be a criminal mastermind, it turned out to be a buffoon who just happened to be more interested in a flash cars and fancy holiday homes than justice and the rule of law.

Ian Buckells (Nigel Boyle) has been part of Line of Duty since season 1 and his rise through the ranks has always been surprising. It turns out that with every promotion in the force, he became more useful to the OCG and more involved, helping to keep the police off their backs.

Not many – if anyone – predicted Buckells to be the Fouth Man and ‘H’. We'd all set off in the wrong directions towards Carmichael, Osborne and co, but the man AC-12 had been chasing all these years turned out to be much closer to home.

Here is everything you need to know about the Line of Duty season 6 finale and all our burning questions…

The Fourth Man was Ian Buckells

Admit it, you didn’t see that coming. The Fourth Man and ‘H’ has been built up for such a long while, it had gained almost mythical proportions. The frustration from Hastings, Kate (Vicky McClure) and Steve (Martin Compston) when they discovered that he was the man pulling the strings for the OCG brushed off on the viewer as well – how had we been duped by blooming Buckells?

But the reality of corruption is that it’s not always committed by smarter, sharper or more cunning people. It’s often just the people who are greedy enough to try it.

Buckells has failed upwards over six seasons of Line of Duty and his incompetence masked his crimes. The bloke couldn’t spell ‘definitely’ correctly, but that doesn’t matter if you’re happy to work with organised crime and pull some strings.

Buckells was the man behind the secret computer messages and he was a middle-man for bent police and the OCG. Alongside Hunter, Fairbank, Cotton, Hilton, Biggeloe and co, he was able to pocket himself a fortune and do very little other than look the other way and call in favours when required.

Why was Buckells so terrified when Lakewell was killed?

This turned out to be a cunning bit of writing by Mercurio. When Lakewell was killed by Carl Banks, we saw Buckells shaking with fear in the cell as the murder took place.

Seeing Buckells act in such a cowardly way and get a warning not to be a rat, threw us off the scent that he had anything to do with Gail Vella or the OCG. He looked like an incompetent victim.

Like Jo Davidson, we saw a hapless police officer in Buckells and didn’t believe that someone so bumbling could be controlling anything.

But as Buckells revealed in his interview, The Fourth Man was never a big scary boss, he was just an intermediate. Following the deaths of Tommy Hunter and Dot Cottan, Buckells had just become a useful connecting point for the disparate OCG groups.

Happy to do favours, clear any blockers or problems caused by the police and take home his share of the cash, Buckells was the perfect cover for the OCG and able to hide in plain sight.

Motivated by greed and allowed to function because the force was too weak and soft on standards and integrity, Buckells failed his way upwards with devastating effect.

The moment he offered Ted Hastings a glass of water to calm down, Buckells’ mask slipped as he smirked at the fact he had got away with so much and for so long, right under the nose of AC-12.

Blast you Buckells, you swine.

What was Ted’s confession?

The most emotional moment of the episode came when Steve and Kate confronted Ted about the cash in Steph Corbett’s attic and the role he played in the death of John Corbett.

The gaffer has been a suspect ever since he dropped John Corbett in it with the OCG, by tipping off Lee Banks that they had a rat in their ranks.

But big old Ted wasn’t guilty of anything other than making a mistake when he was guided by his emotions – Corbett had attacked Ted’s wife, remember.

Ted had hoped that Corbett would hand himself in to the police when Banks shared the intel about their being a rat in the team, but the OCG got to Corbett first.

When Ted discovered Corbett’s mum was a woman “I cared for dearly”, the pain was doubled and that was why he secretly gave the cash to Steph Corbett. He couldn’t face the fact a widow and her kids would end up penniless because of a mistake he made.

Who killed Gail Vella

OCG member Carl Banks was the murderer and the weapon used was found in the safe box under the floor in the weapon warehouse.

It was the murder of Vella that allowed AC-12 to nail Buckells because there was no motive for the OCG to want her dead. But for Osborne and Buckells, keeping her investigations out of the headlines was an urgent priority. And Buckells couldn't get immunity and witness protection without helping AC-12 resolve the death of Vella.

What happened to Terry Boyle?

A happy ending for dear old Terry as not only was he cleared of the Vella murder, but he also got a new home and a big hug from some friends.

After years of bullying and intimidation from rotter Ryan and putting up with Jackie Laverty in his freezer, Terry got his freedom back. Hurrah.

Can Jo Davidson and her dog get a spinoff series?

After years of pyschological abuse and torment from the OCG, Tommy Hunter, Fairbank and Buckells, Davidson (Kelly Macdonald) finally escaped a life living in fear.

AC-12 were able to intercept the OCG’s abduction attempt on her prison truck and save her from a brutal ending. Kate and Steve were also able to offer her immunity and witness protection on the basis that she had been controlled and coerced into her crimes.

Her reward for confessing all was a delightful looking country pad, a new girlfriend and a super cute dog. Give Davidson and that dog a crime-fighting spinoff Jed!

Who was Jo Davidson’s dad?

Davidson’s real dad was Tommy Hunter. But after her mum died, the gang leader convinced Jo that Patrick Fairbank was her father.

Fairbank and Hunter were paedophiles, weasels and a rotten duo. They had abused and used Davidson to help them out, when they needed a clean-cut copper to help them.

Davidson believed that it was Fairbank putting in the orders and controlling her via the computer programme. She never realised it was the bloke in the office next door to her all along.

What was in the OCG’s box under the floor?

The discovery under the workshop floor turned out to be a box filled with murder weapons from previous seasons.

The knives used on Jackie Laverty, John Corbett, Maneet and more were all being kept in case they were required for blackmail purposes.

Back in season 1, the OCG threatened Tony Gates that they could release the weapon with Laverty’s blood and his fingerprints at any time. They used a similar tactic to maintain control of OCG members such as Ryan Pilkington. If anyone had tried confessing or turning rat, they would be able to pin them for murder.

Was Patricia Carmichael bent?

Hastings gave Carmichael both barrels as he hung up his AC-12 boots (“We've stopped standing up for accountability and stopped caring about truth and integrity”) and while there was no evidence of the snooty-nosed inspector being bent, she was definitely guilty of looking the other way.

We saw at the end of the episode, she was one of CC Osborne’s stooges appointed to a newly reorganised anti-corruption unit.

A police officer more interested in promotion and her career than nicking bent coppers, in the eyes of Hastings she was as bad as the rest of them.

Was Lomax bent?

When the abduction of Jo Davidson was set into motion and it had Lomax’s name on the interview sheet, we believed he was about to be revealed as bent.

However, Kate’s signature was also on the sheet requesting an interview with Jo – and we know that was a forgery.

The fact we saw Lomax at the end of the episode investigating the Lawrence Christopher case suggests that he was one of the good guys all along and that his signature was also forged.

A classic red herring throughout the series, Lomax would be a fantastic character to revisit in more detail if the show does return for a seventh season.

And that is the biggest question of them all. The BBC and Mercurio have been coy about plans for a seventh season. This season truly felt like a finale, wrapping up many of the loose ends from previous seasons with throwbacks to Sands View, Corbett, Jackie Laverty, The Caddy and Tommy Hunter.

Revealing Buckells as the Fourth Man closed a long-running storyline in the series and the demolition of anti-corruption by CC Osborne felt like a perfect bittersweet ending. But, but, but…

With over 10 million viewers tuning in every week, three iconic lead characters and plenty of bent coppers still at large – and one big one at the top of the force – there is no reason Mercurio couldn’t reset and start again with season 7.

What are the unanswered questions?

1. Was Fairbank putting on his dementia?

He gave a cold stare at Steve at the end of his interview, which suggested that he may not have been quite as clueless as he claimed.

2. Was Buckells working for Osborne?

The duo came together with Marcus Thurwell in the Lawrence Christopher case and it was that botched investigation and the institutional racism of the officers involved that Gail Vella was exploring with her podcast series.

Buckells had plenty to lose if Vella exposed what really went on in that case, but not anywhere near as much as Osborne did. Buckells hinted that he wasn’t really the man in charge, but he avoided landing the Chief Constable in it.

The closing credit sequence revealed that central police applied for public interest immunity in Buckells’ legal proceedings, which means nobody will ever hear what he reveals. A big hint that Buckells knows plenty about Osborne and could be in his pocket.

3. Is Osborne part of the OCG network?

We’ve known since season 1 that Osborne is an unpleasant and dodgy copper. And the way he’s been closing down AC-12’s investigations and shutting down anti-corruption units suggests that he has plenty to hide.

But is he connected to the OCG and everything Buckells was doing? We might have to wait for season 7 to get that resolved.

4. Steve and Kate finally got a pint of cat piss, but do they have a job?

The duo were happily reunited and we learned in this episode just how much they need each other. Kate was seeing a therapist for her mental health and Steve finally got help for his bad back and painkiller habit. But with Carmichael and Osborne ripping up anti-corruption, it’s not clear where the pair will be working if we get a season 7.

5. Is Ted Hastings retired from the force?

His final rant at Pat Carmichael and the confession about his mistake with Carl Banks and John Corbett felt like closure for the gaffer. Dressed down with the top button on his shirt undone, it looked like Hastings was happy to take the retirement he was offered earlier in the series now The Fourth Man had been found. Does this mean Hastings will just be putting his feet up in season 7?

Watch Line of Duty season 1-6 on BBC iPlayer.