Just when you’d managed to get your head around Terry Boyle and Jackie Laverty’s connections to the latest developments in Line Of Duty, the show has thrown up more references to its complicated past. 

In Sunday night’s episode, we saw the return of OCG member Ryan Pilkington, who is now a fully fledged police officer working alongside DI Kate Fleming on MIT, allowing him to carry on with the gang’s work from the inside. 

There were also some allusions to the events of series three, as AC-12 looked deeper into the reasons for journalist Gail Vella’s murder. 

If you’re in need of a refresh, allow us to explain…

Who is Ryan Pilkington?

Ryan Pilkington is a member of the organised crime group who was first introduced as a child back in series one. 

As a teen, he worked for previous OCG boss Tommy Hunter (who was killed off in series two), and would steal mobile phones and turn them into burner phones before distributing them to blackmailed individuals to receive orders from the OCG. 

He was also a troublemaker on his local estate, with officers PC Karen Larkin and PC Simon Bannerjee apprehending him about his anti-social behaviour. 

Pilkington was involved in the kidnap of series one antagonist DCI Tony Gates, when the OCG were blackmailing him into cooperating with them. Gates’ kidnap saw the officer taken to a warehouse where the body of his former lover Jackie Laverty was being stored in a freezer. Pilkington later helped move Laverty’s body to the flat of Terry Boyle – the man who has now been framed for Gail Vella’s murder in the current series. 

Pilkington also has history with DS Arnott, thus explaining his desire to not be spotted by him when AC-12 raided Hillside Lane. In series one, Arnott was kidnapped by Hunter’s gang, with Pilkington attempting to remove Arnott’s fingers with a pair of bolt cutters. 

The teen was later arrested for an attack on Gates, where he was interviewed by none other than DI Kate Fleming – explaining why she had a flicker of recognition when he joined MIT. While he admitted that he stole phones for Hunter, he denied all other involvement with the OCG and escaped charges. 

Pilkington then returned to Line Of Duty as an adult in series five, this time working as a member of the OCG alongside undercover officer John Corbett. 

He was partly responsible for the death of AC-12’s PC Maneet Bindra, holding her still while Lee Banks slit her throat. She worked as a double agent with the OCG when they threatened to kill her cousin in prison. Pilkington later killed Corbett in the same way after he outed himself as a traitor to the OCG.

At the end of series five, Pilkington was seen attending his police interview seemingly set on embedding himself in the force to carry on with the gang’s work from the inside, and mentioned PC Bannerjee as being a source of inspiration to “turning his life around”. 

Having passed his exams, he is now working as a police officer on DCI Joanne Davidson’s MIT team, alongside former AC-12 officer DI Fleming.  

As we’ve mentioned in this piece, it already looks like he has something to do with the death of the CHIS, Alistair Oldroyd…

Who is Dale Roach?

AC-12’s latest lines of inquiry revealed that any investigative journalism Gail Vella couldn’t broadcast as part of her her day job, she was putting into a podcast. 

Her former bosses told her she’d been looking into the murder case of private detective Daniel Morgan (a real life figure who was murdered in 1987 after it was said he came close to exposing police corruption) and had also been approaching senior police officers about why there’d been a surpression of inquiries into the likes of Dale Roach – a character with links back to series three.

Roach was a former politician and city councillor who had links to organised crime. In the 1990s, he abused many of the young residents of Sands View Boys Home, including Sergeant Danny Waldron. 

Roach and former Chief Superintendent Patrick Fairbank were also said to have fictional links to real-life figure Jimmy Savile, who was one of Britain’s most prolific sex offenders. 

Waldron was the main suspect of AC-12′s investigation in series three after he gunned down a suspect, Ronan Murphy, in cold blood, before convincing his team to make it look as if the dead man was shot first.

AC-12 became suspicious about Waldron’s answers when they brought him in to question him, and Fleming was subsequently placed undercover on his team.

Waldron later lurked at the funeral of the man he killed, and followed one of the mourners, Linus Murphy, before breaking into his home and holding him at gunpoint.

During the showdown, it was revealed Linus and Ronan had abused Waldron as a child while he was living in a children’s home. Waldron killed Linus and returned to his flat, leaving a list of names, which also included Roach, Hunter and Fairbank, in an envelope addressed to DS Arnott. However, this was intercepted by DI Matthew Cottan (aka The Caddy) who stole it. 

DI Lindsay Denton later uncovered a digital copy of the names and sent them to AC-12 just before she was murdered by The Caddy. 

Line Of Duty continues on Sunday at 9pm on BBC One.