| Episode | Title | Original Air Date (UK) | Runtime | | :--- | :--- | :--- | :--- | | 1 | Episode 1 | June 26, 2012 | 60 min | | 2 | Episode 2 | July 3, 2012 | 60 min | | 3 | Episode 3 | July 10, 2012 | 60 min | | 4 | Episode 4 | July 17, 2012 | 60 min | | 5 | Episode 5 | July 24, 2012 | 60 min |

Line of Duty Season 1 is a phenomenal introduction to one of the best British crime dramas of the 21st century. It sets the template: taut interrogations, moral ambiguity, and a relentless focus on the corruption of institutional power. While later seasons are bigger and more twist-heavy, Season 1 is arguably the most disciplined and character-driven.

Note: Unlike later seasons that moved to 6 episodes, Season 1 is a tight 5 episodes. Premise The season introduces AC-12 (Anti-Corruption Unit 12), a fictional police unit dedicated to investigating other police officers. Led by the enigmatic Superintendent Ted Hastings (Adrian Dunbar), AC-12 is called in to probe potential corruption within Central Police. Plot Summary (No Major Spoilers) Detective Sergeant Steve Arnott (Martin Compston), a principled officer transferred to AC-12 after refusing to cover up a colleague's fatal shooting of an unarmed man, is paired with the sharp but weary Detective Constable Kate Fleming (Vicky McClure). Their first major case: investigate Detective Chief Inspector Tony Gates (Lennie James), a celebrated "bent copper" with an outstanding arrest record and a reputation for breaking rules to get results.