'Line of Duty' Casts Robert Carlyle for Season 7

A major reason Jed Mercurio's hit series Line of Duty has been so successful for the BBC is that its premise is dead simple. Three main cast members from the Anti-Corruption Unit 12 ("AC-12") infiltrate subsets of the Birmingham Police force to root out the person undermining their cases. Each season is therefore set in a different office, with a guest star cast that cycles through each case.

Those who have cycled through the series as the main guest star of the season have all been major heavy hitters who have the clout to draw in viewership, creating a roster of A-list names that anyone would want to be a part of. Seasons 1 through 6 featured topline stars Lennie James (Mr. Loverman), Keeley Hawes (Miss Austen), Daniel Mays (Magpie Murders), Thandiwe Newton (Wednesday), Stephen Graham (Adolescence), and Kelly MacDonald (Operation Mincemeat), not to mention a veritable who's who of British talent among the supporting cast.

So when the BBC finally confirmed the show would return for Season 7, the big question was less about what the plot would be or who from AC-12 might come back, and more about who the series would pick to play the latest corrupt cop being pursued. The answer turns out to be another long-standing major figure from the BBC, Robert Carlyle, best known for Trainspotting, The Full Monty, and COBRA.

Here's the synopsis for the forthcoming season:

In Series 7, AC-12 has been disbanded and rebranded the Inspectorate of Police Standards. Anticorruption work has never been more difficult, and in this challenging climate, Steve Arnott , Kate Fleming, and Ted Hastings are assigned their most sensitive case so far.

Detective Constable Shaun Massie is a Specialist Rifle Officer (SRO), a veteran marksman, operating with Tactical Operations Unit 7 (TO-7) to take down Organised Crime Groups. A gruff loner, Massie keeps himself to himself, but when his boss, TO-7's commanding officer DI Dominic Gough, is accused of being a sexual predator, Massie's otherwise detached demeanour changes drastically.

Martin Compston (The Rig), Vicky McClure (Trigger Point), and Adrian Dunbar (Ridley) return to reprise their roles as Steve Arnott, Kate Fleming, and Ted Hastings, respectively. Carlyle will guest star as DC Shaun Massie. The rest of the cast, including other returnees, is expected to be announced closer to filming.

In the press release, Mercurio said the team "couldn't be more thrilled" that Robert Carlyle will star in Series 7 as Specialist Rifle Officer Shaun Massie. "I've been a huge fan of Robert's work for many years," Mercurio stated, "and it will be a career highlight to work with him. Robert always brings mesmerising power and depth to every role; I know viewers will be on the edge of their seats, wondering what his character will do next, and why."

Mercurio will once again pen all episodes of the new season and is slated to split helming duties with director Jennie Darnell across the show's six episodes, with Ken Horn producing. Mercurio also executive produces alongside Simon Heath for World Productions and Nick Lambon for the BBC.

Season 7 is slated to start filming in Belfast in the first half of 2026, and will most likely debut on both the BBC and BritBox in 2027. Seasons 1-6 are available to stream on BritBox.