Line of Duty
Episode 1
TV Flash files “Episode 1” as a desk essential hour — Line of Duty (2012–2021) on BBC, season 4, episode 1, aired 2017-03-26, 60 min.
From the desk
How this hour is filed
This leaf is S04E01: listed hour 18 of 36 in the Line of Duty guide, first listed hour of season 4. It aired 2017-03-26 (60 min). The listed hour before it is “Episode 6” (S03E06). Next is “Episode 2” (S04E02).
Essential hour: “Episode 1”. Season four opens the mania years: appointment interrogation rooms, Hastings catchphrases treated as civic liturgy.

Catalog log
Broadcast listing — not a TV Flash recap.
After months of hunting a serial killer, DCI Roz Huntley faces intense pressure to apprehend a suspect. Michael Farmer is caught and charged with the crimes, but doubts about the young man's guilt lead the chief forensic investigator to AC-12. When DCI Roz Huntley captures a serial killer, Forensic Coordinator Tim Ifield alerts AC-12 to a possible miscarriage of justice.
Viewer FAQ
Where does Episode 1 sit in the Line of Duty guide?
S04E01 is listed hour 18 of 36 — first listed hour of season 4, season 4 episode 1.
When did Line of Duty S04E01 air?
Episode 1 aired 2017-03-26 and is listed at 60 minutes.
Do I need to watch every series in order?
AC-12's long game of institutional rot rewards order. Guest antagonists change; Hastings, Steve, and Kate are the through-line. Skipping a series drops a rung on the conspiracy ladder.
In the series
Why this series still plays
Jed Mercurio's AC-12 interview rooms are gladiatorial: bent coppers, Hastings catchphrases, institutional rot that keeps climbing. British procedural paranoia as national event, scaled all the way to finale mania. Dialogue-heavy thriller craft — the anti-corruption unit as sport, and watercooler television that never needed a car chase.
The first look is an interview-room fluorescent that does more than a car chase. Jed Mercurio's BBC anti-corruption unit AC-12 interrogates bent coppers while institutional rot climbs higher — Martin Compston's Steve Arnott, Vicky McClure's Kate Fleming, Adrian Dunbar's Ted Hastings, plus guest-copper turns from Lennie James, Thandie Newton, Stephen Graham. Long interview scenes are gladiatorial. Catchphrases entered British vernacular. Tessa's tags will gif *Mother of God* until the H speculation Olympics…
Filed against
- Martin Compston as Steve Arnott
Martin Compston sat in the interview room as Steve Arnott on Line of Duty — Jed Mercurio’s AC-12 gladiatorial hours, bent coppers, Hastings catchphrases, institutional rot that keeps climbing. British procedural paranoia as national…
- Vicky McClure as Kate Fleming
Vicky McClure’s Kate Fleming sat Line of Duty’s AC-12 interview rooms like a gladiator — Jed Mercurio’s bent-copper paranoia, Hastings catchphrases, institutional rot that keeps climbing. British procedural as national event, scaled all…
- Adrian Dunbar as Ted Hastings
Adrian Dunbar’s Ted Hastings made Line of Duty’s AC-12 interview rooms a national sport — bent coppers, catchphrases, institutional rot that keeps climbing, Jed Mercurio’s dialogue-heavy thriller as event television. Finale mania…
- Lennie James as Tony Gates
Lennie James's Tony Gates walked Line of Duty into AC-12's gladiatorial interview rooms — Jed Mercurio's bent-copper paranoia, Hastings catchphrases, institutional rot that keeps climbing, British procedural as national event. TV Flash…
- Thandie Newton as Roz Huntley
Thandie Newton interrogated Line of Duty as Roz Huntley — AC-12 interview rooms as gladiatorial sport, bent coppers, institutional rot that keeps climbing, British procedural paranoia as national event. Dialogue-heavy thriller craft. TV…
- Stephen Graham as John Corbett
Stephen Graham’s John Corbett walked Line of Duty’s AC-12 interview rooms like a gladiator — bent coppers, Hastings catchphrases, institutional rot that keeps climbing — then co-signed Adolescence’s four-episode continuous-take trap.…