Line of Duty

Jed Mercurio's Line of Duty launched on BBC One in June 2012 and ran for six seasons until 2021, with multiple BAFTAs including Best Drama Series. The series consolidated Mercurio, after his earlier Bodies and Cardiac Arrest, as the most consistently propulsive British prestige-drama showrunner of his generation. The sixth-season finale in May 2021 drew over 12.8 million UK viewers, the largest UK drama audience for any non-news non-major-event programming in the streaming era.

AC-12, the Anti-Corruption Unit within an unnamed British police force, investigates suspected corrupt police officers across each season's central case. The unit is led by Superintendent Ted Hastings (Adrian Dunbar) and supported by DC (later DI) Kate Fleming (Vicky McClure) and DS (later DI) Steve Arnott (Martin Compston). Each season focuses on a different suspected corrupt officer (Lennie James, Keeley Hawes, Daniel Mays, Thandiwe Newton, Stephen Graham) with substantial sustained-tension extended interview-room sequences that became the show's signature structural commitment.

The series's central conceit (that the British police force is structurally compromised by an organised criminal network operating within it) extended across the full sixth-season arc and was widely received as one of the most-discussed pieces of UK prestige television of its era. Mercurio's commitment to interview-room procedural dialogue (the famous extended-interview sequences) and to an extensive recurring use of police-jargon initialisms (CHIS, OCG, UCO, AC-12) became part of the British public's actual policing-language vocabulary.