Line of Duty season 5 refresher — everything you need to know

Line of Duty Season 5
Line of Duty Season 5 stars Vicky McClure, Adrian Dunbar and Martin Compston. (Image credit: BBC/World Productions Ltd)

Line of Duty Season 5 aired more than two years ago, so if you're looking for a recap of the explosive fifth season look no further. We'll be talking through the key points leading up to Season 6, which is currently airing weekly on BBC One, bringing you up to speed on the most important moments.

Here's the lowdown on Line of Duty season 5. Don't read on if you haven't seen the entire season yet, as we'll be spoiling all of it!

'Line of Duty' Season 5: The main storyline

Line of Duty Season 5 primarily focused on AC-12's investigation into Operation Pear Tree, with the aim of uncovering links between the Organised Crime Syndicate and corrupt police officers within Central Police. 

It was headed up by Detective Superintendent Alison Powell, who clashes with AC-12 and shocks the team when she reveals her insider was actually Detective Sergeant John Corbett, and not Lisa McQueen like they originally assumed.

Meanwhile, PC Maneet Bindra was interviewed by Superintendent Ted Hastings (Adrian Dunbar) DS Steve Arnott (Martin Compston) and DI Kate Fleming (Vicky McClure) after finding out about her involvement with cousin Vihaan Malhotra, who leaked information about AC-12. Episode one's dramatic finale saw Maneet killed by Lee Banks on orders from John Corbett, who doesn't trust her.

From this moment on, Corbett's involvement with AC-12 and the OCS becomes an integral part of the fifth season as he leads a raid on a weapons convoy and goes undercover as a criminal in an attempt to expose the identity of 'H' - a code name referring to a group of senior ranking corrupt police officers within the Central Police.

However, John's got his own twisted ways of getting what he wants, as it is revealed he tortured Roisin Hastings for information about her estranged husband Ted, and his financial situation.

Line of Duty Season 5 John Corbett

John Corbett was a central character in Line of Duty Season 5.  (Image credit: BBC)

What happened to DS John Corbett in 'Line of Duty' Season 5?

John Corbett meets a grisly end in Line of Duty Season 5, as his cover is blown and the truth about his intentions is revealed. In episode four, he is murdered by Ryan Pilkington after trying to escape with Lisa McQueen and rescue trafficked women. It then becomes clear that McQueen had double crossed Corbett.

Pilkington is congratulated for the murder by McQueen, who tells him to lay low and ensure he passes his exams which will allow him to act as a mole inside Central Police. Following McQueen's arrest, she lies to DI Fleming and DS Arnott about Corbett's murder, allowing Pilkington to get away with it and integrate into Central Police. 

What happened in the season finale?

Line of Duty Season 5 has an intense final episode, as we see Ryan Pilkington enrolling as a student police officer, just like Lisa McQueen had intended. In addition to this, McQueen herself is let off the hook and  given an immunity deal in exchange for a testimony about senior members of the OCG.

Meanwhile, Ted Hastings is suspended and conspiracy charge is brought on by DCS Patricia Carmichael, but it is later revealed that lawyer Gill Biggeloe was involved in bringing DS John Corbett into Operation Pear Tree. She is exposed as a member of the OCG, and Hastings' position as leader of AC-12 is reinstated with a final written warning about his conduct.

When Season 5 draws to a close, there's still a lot of mystery surrounding the true identity of 'H'. H is – or we think is – not one but four corrupt officers. The revelation that H was not just one individual but actually a group of officers was revealed by DI Matthew Cottan (Craig Parkinson) as his dying declaration in Series 3.

So far the names that have been identified are Cottan himself, Derek Hilton and Senior Legal Counsel Gill Biggeloe, leaving one name that we are still yet to discover.

Season 6 has picked up with DCI Joanne Davidson (Kelly Macdonald) heading up Operation Lighthouse, an investigation into the murder of journalist Gail Vella.

Is there a trailer for 'Line of Duty' Season 5?