All Major Actors & Cast List for Slow Horses Season 4

The Apple TV+ original series Slow Horses is about to premiere its fourth season, adapting the Novels by writer Mick Herron. This new season will be an adaptation of Spook Street, the fourth entry in the book series. Here are all the major actors and cast list for Slow Horses Season 4.

All Major Actors & Cast List for Slow Horses Season 4

Gary Oldman as Jackson Lamb

Jackson Lamb is head of Slough House, the division of MI6 that disgraced agents are sent to punish or force them to quit. That’s where Lamb comes in, a Cold War legend so traumatized by his past he lets it all out with his flatulent humor and excessive drinking. Lamb was given Slough House and control of the Slow Horses as a reward for his service – making his abuse of them an essential part of his job. However, that doesn’t mean he isn’t concerned about their safety.

Oldman is best known for roles such as Commissioner Gordon in Christopher Nolan’s Dark Knight Trilogy and, more recently, as President Harry S. Truman in the Oscar-winning Oppenheimer.

Jack Lowden as River Cartwright

Jack Lowden plays River Cartwright, an MI6 agent who disgraces himself in the worst possible way during a public training exercise at the start of the series. This leads to him being the audience’s way into Slough House, where we learn all about the Slow Horses. River takes more of a central role in this newest season, which revolves around his grandfather’s declining mental health as secrets from his past begin to come back to haunt him.

Lowden is also a Christopher Nolan film alumni, playing a pivotal role in 2017’s Dunkirk, and more recently has appeared in the second season of The Rings of Power as Sauron.

Kristin Scott Thomas as Diana Taverner

Diana Taverner is the foil to Jackson Lamb and the Slow Horses and is the Second Desk in MI6. Taverner is a bureaucrat character with aspirations for the highest position in British Intelligence Services (First Desk) and will use and exploit anyone — Slow Hores included — to get there.

Kristin Scott Thomas is known for her Oscar-nominated role in 1996’s The English Patient.

Hugo Weaving as Frank Harkness

Hugo Weaving plays Frank Harkness, a new antagonist introduced in Slow Horses Season 4. Frank is an American expat with grand machinations as an independent contractor for various intelligence services or anyone willing to foot the bill. Harkness has a dark connection to River’s grandfather, David Cartwright. Frank will no doubt serve as the sinister force driving the events of the season.

Hugo Weaving is known for his roles as Agent Smith in the Matrix films, Elrond in the Lord of the Rings and Hobbit movies, and most recently as the Red Skull in Captain America: The First Avenger, making the actor no stranger to villainous roles.

Jonathan Pryce as David Cartwright

Jonathan Pryce plays David Cartwright, River’s grandfather who was a legend in the British Intelligence Services and Jackson Lamb’s former boss. David Cartwright has mainly been in the background for the past three seasons, and Season 4 is set to bring the character and his dark past to the forefront, all while David is dealing with a mental illness that has him forgetful or unknowing of what is real or not.

Jonathan Pryce is known for playing Prince Phillip in the final two seasons of Netflix’s The Crown.

Related: Is Slow Horses Based on a True Story?

Full Cast of Slow Horses Season 4

Plenty of other actors make up the rest of the Slow Horses and other members of MI6 in the series, including new addition Tom Brook as JK Coe and a new head of the Dogs, Emma Flyte, played by Ruth Bradley. Besides those new additions, here is the complete list of every cast member in Slow Horses Season 4:

Jackson Lamb – Gary Oldman

River Cartwright – Jack Lowden

Diana Taverner – Kristin Scott Thomas

David Cartwright – Jonathan Pryce

Frank Harkness – Hugo Weaving

Catherine Standish – Saskia Reeves

Louisa Guy – Rosalind Eleazar

Roddy Ho – Christopher Chung

Shirley Dander – Aimee-Ffion Edwards

Marcus Longridge – Kadiff Kirwan

Moira Tregorian – Joanna Scanlan

J.K. Coe – Tom Brooke

Emma Flyte – Ruth Bradley

Claude Whelan – James Callis

“Bad” Sam Chapman – Sean Gilder

Molly Doran – Naomi Wirthner

Slow Horses is streaming on Apple TV+