Slow Horses season 5: Release date speculation and latest news

The new season upped the ante in so many ways, and left fans itching for more – thankfully, they're in luck, as it is not only return for one season, but for two.

The show's fifth season, which was confirmed some time ago, will be based on Mick Herron's fifth Slough House novel, London Rules, while season 6 will be based on the sixth and seventh novels, Joe Country and Slough House. Season 5 has already been filmed, and a short teaser appeared at the end of the season 4 finale.

Fans just recently got some additional news about the show going forward, with Hugo Weaving, who appeared in season 4 as Frank Harkness, confirming his return for season 6.

Beyond the seventh novel, there is one more in Herron's core series which is currently available, while there is another on the way. Showrunner Will Smith previously weighed in on the chances the series will adapt them all, saying: "Depends on what Apple wants and what the appetite is, but I definitely have the kind of leave-them-wanting-more rather than the outstay-your-welcome instinct.

"But the world of the show is there to be mined."

But when can fans expect Slow Horses season 5 to arrive on Apple TV+, what will it be about and who from the cast will be returning to their roles? Read on for everything we know.

When will Slow Horses season 5 be released?

We don't yet know exactly when Slow Horses season 5 will be released, but fans shouldn't have to wait too long.

The series has been remarkably efficient at releasing new seasons in a timely manner, with seasons 1 and 2 airing in 2022, season 3 arriving in November 2023 and season 4 coming to screens in September 2024.

The show was officially renewed for season 5 in January 2024, and has already been filmed. Given this, we'd guess it could arrive around summer 2025, just a bit less than a year after season 4.

We will keep this page updated once we get any more concrete news.

What will Slow Horses season 5 be about?

Slow Horses season 5 will be based on the fifth novel in Mick Herron's Slough House series, London Rules.

An official synopsis has already been released for the season, which teases: "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, Jackson Lamb knows that in the world of espionage, 'London Rules' should always apply."

Beyond this, we also have the blurb to go on from the London Rules book - although, of course, changes could have been made to this in the adaptation.

The blurb says: "At Regent's Park, the Intelligence Service HQ, its new chief Claude Whelan is learning the job the hard way.

"Tasked with protecting a beleaguered Prime Minister, he's facing attack from all directions: from the showboating MP who orchestrated the Brexit vote, and now has his sights set on No. 10; from the showboat's wife, a tabloid columnist, who's crucifying Whelan in print; and especially from his own deputy, Lady Di Taverner, who's alert for Claude's every stumble.

"Meanwhile, the country's being rocked by an apparently random string of terror attacks. Over at Slough House, the last stop for washed-up spies, the crew are struggling with personal problems: repressed grief, various addictions, retail paralysis, and the nagging suspicion that their newest colleague is a psychopath.

"But collectively, they're about to rediscover their greatest strength - making a bad situation much, much worse."

Who will star in Slow Horses season 5?

We're expecting the majority of the main cast of Slow Horses to be back, and know we'll certainly be seeing more of Gary Oldman's Jackson Lamb, Kristin Scott Thomas's Diana Taverner, Jackson Lowden's River Cartwright and Rosalind Eleazar's Louisa Guy, among others.

There are some characters whose returns are less certain. While Jonathan Pryce could certainly return as David Cartwright, the end of season 4, in which River set him up in a retirement home, may well spell the end of his time on the show.

Meanwhile, we know that Hugo Weaving's Frank Harkness will also return, but it seems he's unlikely to be back in season 5, and will instead return in season 6.

Weaving confirmed this when speaking at the International Film Festival of India in Goa, as reported by Variety, with the actor saying he would be returning to London in January 2025 for a two-and-a-half month shoot.

He said: "Each season generally is a book, but also each season departs a little bit from those books. We’re getting to the point with Slow Horses where the seasons are catching up to the amount of books that [Mick] Herron has written."

He had previously told Forbes of his potential return: "You probably know that Frank is in one of the other books, and so the assumption is at the end of this season, and certainly to anyone who had read the books, is that Frank will be coming back.

"Frank gets to play his Get Out of Jail Free card, which he has had all along because he knows that MI5 and David Cartwright tried to set him up. He knows he's got that, so he can say that fabulous line, 'I'll get the next train.' He can be that sort of a character because he actually is a survivor and excellently slippery."

Joanna Scanlan could also come back as Moira Tregorian, but now she's got her job at the Park back and left Slough House, she could be a one-and-done character.

Finally, one character we almost certainly won't see more from is Kadiff Kirwan's Marcus Longridge, after he met his tragic end during the season 4 finale.

Here's a list of some of the characters we feel certain we'll see back for season 5 at this stage:

• Gary Oldman as Jackson Lamb
• Kristin Scott Thomas as Diana Taverner
• Jack Lowden as River Cartwright
• Rosalind Eleazar as Louisa Guy
• Christopher Chung as Roddy Ho
• Aimee-Ffion Edwards as Shirley Dander
• Ruth Bradley as Emma Flyte
• Tom Brooke as JK Coe
• James Callis as Claude Whelan

Is there a trailer for Slow Horses season 5?

There isn't a trailer for Slow Horses season 5 online yet, even though one did air at the end of the show's final episode on Apple TV+.

You can head to streamer to watch that teaser now, and once one becomes available online we will update this page.

For now, you can rewatch the season 4 trailer below.

Slow Horses seasons 1-4 are available to watch now on Apple TV+ – sign up to Apple TV+ now.

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