Detective Superintendent Ian Buckells is back for another season of Line of Duty, once again playing a pivotal role in Jed Mercurio's complex and clever storyline plotting.
But Season 6 isn't the first time Line of Duty fans have seen shady Ian Buckells on their screens.
Here is everything you need to know about the character...
Who is DSU Ian Buckells?
There is no love lost between Jo Davidson and her boss, especially when it comes to Operation Lighthouse, the investigation into the murder of journalist Gail Vella.
Most recently Ian has come to the attention of Superintendent Ted Hastings (Adrian Dunbar) and his team at AC-12 after many of his actions appeared to prove he is a corrupt member of the police force.
Not only was he the one who apparently brought in the late Ryan Pilkington, who we know was actually working undercover in the police for the OCG, but also he was the one who messed up surveillance on Beechwood House on the day of Terry Boyle's arrest. He also appeared to have the missing Gail Vella files in his car.
Since this evidence came to light it has been confirmed by Jo Davidson in her AC-12 interview in episode 5 that she had framed Buckells for most of his dodgy wrongdoings in connection to the Gail Vella murder.
It has also been revealed that the witness, Deborah Devereux, who identified Terry Boyle as the man talking to the CHIS about Gail Vella's murder actually owed Buckells a favour. The pair had also been exchanging messages, proving her witness account was false.
But, the question still remains, is Buckells corrupt or just incompetent?
When did we first see Ian Buckells in 'Line of Duty'?
We first saw Ian Buckells in Season 1 when he was part of the investigation into Jackie Laverty's disappearance - yes, the very same Jackie Laverty who has been stored in Terry Boyle's freezer since Season 1.
But, to make Ian look shifty from the start, he was actually brought into the investigation by Superintendant Derek Hilton, who later turned out to be part of the H line up - the codename for a group of four corrupt officers.
Buckells then reappeared in Line of Duty in Season 4 when he was brought in to replace AC-12 antagonist DCI Roz Huntely on Operation Trapdoor. He wasn't happy about having Kate working undercover on the team for AC-12 and was eventually accused of being the one who blew Kate's cover.
Who plays DSU Ian Buckells?
DSU Ian Buckells is played by actor Nigel Boyle. Nigel is no stranger to UK TV and has appeared in shows like Peaky Blinders, Inbetweeners, Silent Witness, Casualty, Doctors, Peep Show and This Time with Alan Partridge to name but a few. He has appeared in Coronation Street twice, once in 2012 as a solicitor and again in 2015 as a character called Joe, a friend of Luke Britton.
Is Ian Buckells corrupt?
With the evidence stacking up against him in Season 6 episode three, it certainly looks that way. But while it is likely he has been framed for a lot of his actions by Jo Davidson, it also seems that Buckells is far from squeaky clean even without Jo's involvement.
Not only has he had some seriously suspicious links to corrupt officers like Marcus Thurwell and Chief Constable Philip Osborne over the years, he has also been linked to past investigation cover ups including the Lawrence Christopher killing.
Some fans are convinced that he is is linked to the H gang and OCG because of the golf clubs that have been spotted in his office. Viewers will remember that corrupt officers have been linked to the sport since OCG leader Tommy Hunter was seen playing golf in Season 1.
DI Dot Cottan was also nicknamed 'The Caddy' - and he is renowned for his part as one of the four H's. But are Buckells' golf clubs a not-so-hiddn clue that he is corrupt, or just a big red herring from Jed Mercurio?
The Season 6 Line of Duty finale airs on Sunday 2nd May at 9pm on BBC One. You can catch up on past series and missed episodes on BBC iPlayer.
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