Slow Horses Cast (2022–present)
Apple TV+ | Spy Thriller, Drama | 4+ Seasons | Based on Mick Herron's Slough House novels | Adapted by Will Smith
Slow Horses is an Apple TV+ spy thriller series adapted from Mick Herron's acclaimed Slough House novels, beginning with the first book published in 2010. The series centres on Slough House, a shabby annexe of MI5 where disgraced intelligence officers — the so-called "slow horses" — are sent to perform bureaucratic make-work in the hope that they will eventually resign. Presided over by the magnificently repellent Jackson Lamb, these rejects find themselves repeatedly drawn into the kind of high-stakes operations that their official superiors would prefer to keep them away from. Each season of the television series adapts one novel, introducing new threats and guest characters while developing the rich ongoing ensemble of Slough House regulars.
The Slow Horses cast is built around one of the most acclaimed television performances in recent British drama: Gary Oldman's portrayal of Jackson Lamb, a man simultaneously repulsive and magnetic, whose genius-beneath-the-surface makes every scene he occupies electrifying. The wider Slow Horses cast features an outstanding ensemble of British character actors — Jack Lowden, Kristin Scott Thomas, Saskia Reeves, Jonathan Pryce — who have made the show one of Apple TV+'s most critically respected originals. With Kristin Scott Thomas delivering a masterclass in elegant menace as MI5's power-hungry Diana Taverner, and Jonathan Pryce lending emotional weight as River's grandfather, the cast operates at a consistently high level across every season.
Main Cast
Gary Oldman
Jackson Lamb
The head of Slough House — slovenly, rude, flatulent, and apparently incompetent, but in reality a former Cold War legend whose instincts remain razor-sharp. Oldman's portrayal has been described by critics as one of the great character performances in television history.
Jack Lowden
River Cartwright
A young, ambitious MI5 officer banished to Slough House after a training exercise that went catastrophically wrong. River is the closest thing the series has to a conventional hero, but the show consistently interrogates and complicates that role. Lowden plays him with impressive restraint and warmth.
Kristin Scott Thomas
Diana Taverner
The First Desk of MI5, a supremely ambitious and politically astute operator who views Slough House as a useful but disposable asset. Scott Thomas brings a glacial intelligence to a character who is never quite the villain but never entirely trustworthy.
Saskia Reeves
Catherine Standish
Lamb's long-suffering administrator and the institutional memory of Slough House. Catherine is a recovering alcoholic whose quiet competence and moral steadiness make her one of the most indispensable people in the building. Reeves gives the role a tremendous dignity.
Rosalind Eleazar
Louisa Guy
A capable field agent whose time at Slough House has been defined by personal loss as much as professional humiliation. Eleazar gives Louisa a tough exterior that the series takes care to crack open over successive seasons.
Christopher Chung
Roddy Ho
Slough House's tech specialist — a social outcast of staggering self-regard whose hacking skills are arguably the best in the building. Chung plays him with brilliant comic precision, making Roddy simultaneously insufferable and endearing.
Jonathan Pryce
David Cartwright
River's grandfather, a former MI5 legend known as the "Old Bastard," whose distinguished career in British intelligence left a complicated legacy for his grandson. Pryce brings warmth and melancholy to one of the show's most treasured recurring roles.
Aimee-Ffion Edwards
Shirley Dander
A combative, reckless agent with anger-management issues and a hair-trigger temper. Shirley is one of the ensemble's most volatile characters, and Edwards plays her energy with tremendous physical commitment and dark comic flair.
Supporting & Recurring Cast
| Actor | Character | Role | Seasons |
|---|---|---|---|
| Jonathan Pryce | David Cartwright | River's grandfather; a retired MI5 legend whose past shapes the present | 1–present |
| Aimee-Ffion Edwards | Shirley Dander | Combative, reckless Slough House agent; major ensemble regular | 1–present |
| Freddie Fox | Marcus Longridge | Shirley's partner in the field; another Slough House regular | 1–present |
| Tom Brooke | Struan Loy | A newer addition to the Slough House ensemble in later seasons | Selected seasons |
| Kadiff Kirwan | Marcus Longridge | Originally played Marcus; Slough House field operative | Season 1 |
| Paul Higgins | Nick Duffy | MI5's head of internal security; a recurring antagonist to the Slough House team | 1–present |
| Olivia Cooke | Sid Baker | River's close associate; prominent in Season 1 before moving on | Season 1 |
| Saskia Reeves | Catherine Standish | Slough House administrator; Lamb's de facto deputy | 1–present |
Creators & Production
Mick Herron
Source Material — Herron's Slough House novel series, beginning with Slow Horses (2010), provides the basis for the television adaptation. Herron is widely considered the finest British spy novelist writing today, and the books have won multiple Crime Writers' Association awards.
Will Smith
Lead Writer & Adapter — Smith (the British screenwriter, not the actor) adapted Herron's novels for the screen, maintaining the books' sardonic voice and complex plotting while making the changes necessary for a prestige television format.
James Hawes
Lead Director — Hawes directed the first two seasons of Slow Horses, establishing the show's visual grammar: muted colours, cramped interiors, and a sense of perpetual institutional shabbiness that perfectly mirrors the world of Slough House.
See-Saw Films
Production Company — Slow Horses is produced by See-Saw Films, the London- and Sydney-based company responsible for The King's Speech, Top of the Lake, and other prestige drama productions.
Apple TV+
Network — Slow Horses streams exclusively on Apple TV+ globally and has become one of the platform's most critically decorated originals, regularly appearing on year-end best-of-television lists since its 2022 premiere.
About the Slow Horses Cast
The defining casting decision for Slow Horses was Gary Oldman accepting the role of Jackson Lamb. Oldman, one of the most celebrated character actors of his generation — an Academy Award winner for Darkest Hour (2017) who has played everyone from Winston Churchill to Sirius Black to Commissioner Gordon — committed entirely to a performance that requires him to be physically unrecognisable from his usual screen presence. Lamb is unwashed, overweight, and deliberately off-putting, yet the series demands that audiences understand his genius and even, eventually, his peculiar form of loyalty to his team. Oldman achieves all of this with extraordinary precision, and his work on Slow Horses has prompted widespread discussion of it as among the finest of his career. He serves as an executive producer on the show in addition to playing the lead role, which speaks to his investment in the material.
The ensemble around Oldman was assembled with equal care, drawing heavily from the deep pool of British theatrical talent. Jack Lowden, known for his stage work and for films including Dunkirk and Calibre, brings a grounded, unpretentious quality to River that stops the character from ever becoming a straightforward hero. Kristin Scott Thomas — with a career spanning Four Weddings and a Funeral, Gosford Park, and The English Patient — uses her natural aura of patrician elegance as a weapon for Diana Taverner, making every measured word feel like a potential trap. The cumulative effect of this calibre of ensemble across four seasons has made Slow Horses one of the most consistently praised programmes streaming anywhere in the world.
Frequently Asked Questions
Who stars in Slow Horses?
Slow Horses stars Gary Oldman as Jackson Lamb, the brilliant but deeply eccentric head of MI5's Slough House — a dumping ground for disgraced intelligence officers. Jack Lowden co-stars as River Cartwright, Lamb's most capable but perpetually frustrated agent, and Kristin Scott Thomas plays Diana Taverner, the ambitious deputy director of MI5.
Who plays Jackson Lamb in Slow Horses?
Gary Oldman plays Jackson Lamb, the slovenly, rude, and unpredictable head of Slough House who nonetheless turns out to be one of the sharpest minds in the British intelligence community. The role has been widely described as one of the finest performances of Oldman's career.
What is Slow Horses based on?
Slow Horses is based on the Slough House novel series by British author Mick Herron, beginning with the first book Slow Horses (2010). Each season of the TV series adapts one of Herron's novels, with the writer credited as one of the finest spy fiction authors working today.
How many seasons of Slow Horses are there?
Slow Horses has aired four seasons on Apple TV+ as of 2024–2025, with each season adapting one of Mick Herron's Slough House novels. The show has been renewed for additional seasons and continues to attract strong critical praise.
Is Jonathan Pryce in Slow Horses?
Yes. Jonathan Pryce plays David Cartwright, River's grandfather and a former MI5 legend whose past continues to cast a long shadow over the events of the series. Pryce's scenes with Jack Lowden are among the most emotionally resonant in the show.
How we build these cast lists
For background on how Cast.biz compiles and orders cast credits, see understanding billing order, how TV show casts are built, and our glossary of cast credits.