Streaming availability may change — check BritBox for current availability. Spoiler-free throughout, including no reveal of "H".
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What Is Line of Duty About?
Line of Duty follows AC-12, a fictional anti-corruption unit tasked with investigating police officers suspected of corruption from within their own force. Unlike most British mysteries, it isn't a new case in a new village each week — it's one long, tightly serialized story, with a running mystery about the identity of a corrupt senior officer known only as "H."
| Setting | Fictional English police forces, filmed largely in Belfast |
| Format | Serialized, must be watched in order |
| First aired | 2012 |
| Created by | Jed Mercurio, an original story (not based on books) |
| US rating | TV-MA on BritBox |
Where Should a Beginner Start?
Start at the Very Beginning
There's no alternate entry point here — Line of Duty tells one continuous story, and Series 1 introduces the AC-12 trio, the format, and the case that sets everything else in motion.
Watch via BritBox on Prime Video →The Guest Leads
Martin Compston, Vicky McClure, and Adrian Dunbar anchor AC-12 throughout, but each series brings in a new, high-profile guest lead as the officer under investigation.
Series 1–6
Lennie James, Keeley Hawes, Daniel Mays, Thandiwe Newton, Stephen Graham, and Kelly Macdonald have each led a series as the officer AC-12 investigates.
Series 7 (Coming 2027)
AC-12 has been disbanded and rebranded as the Inspectorate of Police Standards. Robert Carlyle joins as DC Shaun Massie, a Specialist Rifle Officer, opposite the returning core trio.
Where to Watch
All six series are available in order on BritBox in the US — watch them that way, since the story builds continuously.
Where to watch in the US
BritBox
All 6 series · Subscription required · Check current price at signup
View BritBox Options →Streaming availability in the US can change. Check the linked service for the current season and episode selection.
More for Line of Duty Fans
Frequently Asked Questions
Do I need to watch Line of Duty in order?
Yes. Unlike many British mysteries, Line of Duty builds one long-running story across all six series, with a returning cast of officers and an overarching mystery. Watching out of order will spoil major twists.
What does AC-12 mean?
Anti-Corruption Unit 12, the fictional police unit at the center of the show, tasked with investigating officers suspected of corruption within their own force.
Who are the main characters in Line of Duty?
DS Steve Arnott (Martin Compston), DI Kate Fleming (Vicky McClure), and Superintendent Ted Hastings (Adrian Dunbar) anchor AC-12 across all six series. Each series also brings in a new guest lead under investigation, played by a different well-known actor.
Who is "H" in Line of Duty?
The identity of H, a corrupt senior officer tied to organized crime, was one of British television's most talked-about mysteries and was resolved in the Series 6 finale. British TV Hub won't spoil it here — watch the show to find out.
How many series of Line of Duty are there?
Six series have aired so far (2012–2021), all streaming on BritBox in the US. A seventh series has finished filming and is expected to air in 2027.
Is Line of Duty coming back for a Series 7?
Yes. The BBC confirmed a seventh series, which finished filming in Belfast in mid-2026. Martin Compston, Vicky McClure, and Adrian Dunbar all return, joined by Robert Carlyle as the new guest lead, DC Shaun Massie. It's expected to air in 2027.
Where can I watch Line of Duty in the US?
BritBox is Line of Duty's main US streaming home, with all 6 series available.
Is Line of Duty based on real events or books?
No. It's an original creation by writer Jed Mercurio, a former hospital doctor who also created Bodyguard. He wrote every one of the show's 36 episodes himself.
Affiliate disclosure: British TV Hub is a participant in the Amazon Associates program and earns from qualifying purchases. Some links on this page may be affiliate links to BritBox. This never affects the recommendations — these are genuine editorial favourites.
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