The 'Slow Horses' Season 5 Trailer Puts Slough House in Lockdown

In a landscape where multiple streaming services currently in existence are probably not going to be around much longer, Apple TV+ stands alone as a singular, yet improbable success story. As a content provider with zero experience making its own original series, its launch in 2019 was heavily overshadowed by the initial smashing success of Disney+; its paltry four shows on launch day were more "what tech bros think prestige TV looks like" than actually entertaining. However, as the streaming service rounds into its sixth year of existence, it has become a dependable source of British programming, including the popular Slow Horses series, which debuts Season 5 in late September 2025.

There were several fortuitous events, including a mass exodus from HBO in 2021 ahead of Warner Bros.' ill-fated merger with Discovery, many of whom were scooped up by Apple. However, as is true with most hit shows, the streaming service was also lucky. Ted Lasso arrived at a dark moment when everyone wanted a weekly thirty minutes of positivity. Conversely, Severance's dour first season was initially overlooked, but by the time Season 2 arrived in early 2025, audiences were ready for a show that promised their paranoia about the world wasn't merely justified; things were even worse than they could comprehend.

Meanwhile, Slow Horses has been the glue that has helped hold the streaming service together. A highbrow version of your standard "case of the season" spy series, the show has never been the most-watched in Apple's lineup, but it is the most dependable. That's why the show has already been greenlit for Seasons 6 and 7, and its first spinoff, Down Cemetery Road, will premiere at the end of October. 

Season 5 will cover the events from author Mick Herron's fifth book in The Slough House Series, London Rules. Here's the synopsis for the forthcoming season:

In Season 5 of Slow Horses, everyone is suspicious when resident tech nerd Roddy Ho has a glamorous new girlfriend, but when a series of increasingly bizarre events occur across the city, it falls to the Slow Horses to work out how everything is connected. After all, Lamb knows that in the world of espionage, the London Rules — cover your back — always apply.

Newly knighted Sir Gary Oldman (Oppenheimer) returns as Jackson Lamb, with Jack Lowden (The Gold) as River Cartwright and Kristen Scott Thomas (My Mother's Wedding) as Diana Taverner. The rest of the core cast set to return includes Saskia Reeves (Roadkill) as Catherine Standish, Rosalind Eleazar (Missing You) as Louisa Guy, Christopher Chung (Blitz) as Roddy Ho, Aimee-Ffion Edwards (Wolf Hall) as Shirley Dander, and Jonathan Pryce (The Crown) as David Cartwright. 

Season 4 introduced several guest stars, some of whom are now officially part of the team going into Season 5, including Joanna Scanlan (Riot Women) as Moira Tregorian, Ruth Bradley (Guilt) as Emma Flyte, and Tom Brooke (Bodyguard) as J.K. Coe. Season 5's major guest star will be Nick Mohammed (Renegade Nell).

Slow Horses' longtime lead writer, Will Smith, penned all episodes of Season 5 with returning Season 3 director Saul Metzstein helming all installments. Smith, Metzstein, and Oldman are listed as executive producers, alongside Jamie Laurenson, Hakan Kousetta, Julian Stevens, Iain Canning, Emile Sherman, Gail Mutrux, Douglas Urbanski, and Graham Yost.

Slow Horses Season 5 is set to debut on Wednesday, September 24, 2025, with the first two episodes, followed by one episode per week through October. Seasons 6 and 7 are expected to follow in 2026 and 2027, respectively. Seasons 1 through 4 are streaming on Apple TV+.