Line of Duty

Line of Duty follows DS Steve Arnott (Martin Compston), an authorised firearms officer who was transferred to Anti-Corruption Unit 12 (AC-12) after refusing to agree to cover up an unlawful shooting by his own team. At AC-12 Arnott is partnered with DC Kate Fleming (Vicky McClure), a highly commended undercover officer with a keen investigative instinct. They work under the supervision of Superintendent Ted Hastings (Adrian Dunbar), who is one of several Senior Investigating Officers (along with DCS Patricia Carmichael (Anna Maxwell Martin) of AC-3 and those of AC-9) responsible for uncovering corruption within the police force. Throughout the series, AC-12 investigate seemingly disparate cases involving seemingly-corrupt police officers such as DCI Tony Gates (Lennie James), DI Lindsay Denton (Keeley Hawes), Sergeant Danny Waldron (Daniel Mays), DCI Roseanne Huntley (Thandie Newton), and undercover officer DS John Corbett (Stephen Graham). AC-12 realise the pervasive nature of corruption and the police's deep-rooted links to an organised crime group.

• Martin Compston as Detective Sergeant Steve Arnott, assigned to AC-12, the anti-corruption unit within the Central Constabulary. Previously, he served as a counter-terrorism officer. He transferred after he refused to collude with his colleagues following the fatal shooting of an innocent man.
• Vicky McClure as Detective Inspector Kate Fleming, an undercover specialist and consummate professional, Fleming is willing to investigate officers inside and outside AC-12. Initially a detective constable, she is promoted to detective sergeant at the end of the third series and to detective inspector following the fourth. She is married with a son.
• Adrian Dunbar as Superintendent Ted Hastings, the senior investigating officer of AC-12. He recruited Arnott, Fleming and Cottan. Once a member of the Royal Ulster Constabulary, he is a Roman Catholic and a Freemason.
• Craig Parkinson as Detective Inspector Matthew "Dot" Cottan (series 1, 2 & 3), an AC-12 officer, initially introduced as a Sergeant on Tony Gates's TO-20 team. At the beginning of series two, he is promoted to detective inspector and transferred to AC-9. He is seconded to AC-12 by Hastings. Cottan is revealed to be "The Caddy", working as a fixer for an organised crime group. He is killed at the close of the third series having escaped from AC-12 custody.
• Lennie James as Detective Chief Inspector Anthony "Tony" Gates (series 1), the head of the serious crime unit TO-20, Gates is renowned for returning the best crime figures of any unit in the Central Constabulary. It is this reputation, however, that leads AC-12 to his team. Suspected of corruption, Gates faces an internal affairs investigation that adds further complications to his troubled home life.
• Keeley Hawes as Detective Inspector Lindsay Denton (series 2 & 3), a silver commander who organises a convoy to transport a protected witness that is ambushed, resulting in the deaths of all the other police officers. As the only police survivor, Denton is charged with conspiracy to commit murder. She attempts to convince AC-12 of her innocence and regain her reputation, but eventually receives a life sentence. In series 3, Denton is granted an appeal, and is acquitted on the basis of an improper sexual relationship Arnott had with her while she was being investigated. She discovers crucial evidence pertaining to the Danny Waldron murder investigation and historical child sex abuse, but after refusing to accept a bribe to conceal that evidence, she is murdered by Cottan.
• Daniel Mays as Sergeant Danny Waldron (series 3) is an Authorised Firearms Officer (AFO). His armed response unit is investigated by AC-12, as a matter of routine following the shooting of a suspect. A deeper investigation is initiated when Arnott and Fleming discover the shooting may have been unlawful. Waldron is shot and killed by a colleague; his death results in an investigation into historic child sex abuse.
• Thandie Newton as Detective Chief Inspector Roseanne "Roz" Huntley (series 4), the senior investigating officer of Operation Trapdoor, at the centre of an AC-12 investigation for mishandling evidence.
• Stephen Graham as Detective Sergeant John Corbett (series 5), Corbett is an undercover police officer who has been uncontactable for several months. He first appears as John Clayton, the gangleader of an organised crime group which hijacked a police convoy transporting seized drugs.
• Anna Maxwell Martin as Detective Chief Superintendent Patricia Carmichael (series 5), the senior investigating officer of AC-3, who is drafted in to review AC-12's handling of the Corbett investigation.
• Kelly Macdonald as Detective Chief Inspector Joanne Davidson, the senior investigating officer of an unsolved murder, whose unconventional conduct raises suspicions at AC-12.[6][15][16]

Line of Duty was created and written by Jed Mercurio. The first two series were produced by World Productions, on behalf of BBC Two. David Caffrey and Douglas Mackinnon directed series one. Mackinnon directed the first three episodes of series two and Daniel Nettheim directed the remaining three episodes. Mercurio produced series one and acted as executive producer for series two, with Peter Norris taking over as producer for series two.

In the United States, the first series was released on Hulu in August 2012 as an exclusive series, until Acorn TV picked up the streaming rights for its platform in 2018, which included the existing series and exclusive access to series five and later additions.[43][44] The first three series began airing on AMC on 4 April 2020.[45][46]

• Line of Duty at BBC Programmes
• Line of Duty at IMDb
• Line of Duty at epguides.com
• Line of Duty at TV.com
• Line of Duty, scripts at BBC TV Drama archive