When Gary Oldman stepped off the set of Slow Horses after filming wrapped earlier this year, he didn’t just close a season — he handed off a legacy. The Oscar-winning actor, 66, confirmed in a January 9, 2025 interview with ScreenRant that Season 6 of Slow Horses is officially in post-production, with a planned Apple TV+ debut in Fall 2026. And here’s the twist: while fans wait for the next chapter of Jackson Lamb’s chaotic spy unit, production on Season 7 is already set to begin in late October 2025 — meaning the world of Slough House is moving faster than ever.

From Book to Screen: A New Narrative Approach

For the first time since the series began in April 2022, Season 6 will weave together plotlines from two of Mick Herron’s Slough House novels: Joe Country and Slough House. That’s not just ambitious — it’s a gamble that pays off for longtime readers. The show’s writers, led by new showrunner Gaby Chiappe, are no longer constrained to adapting one book per season. This shift allows them to deepen character arcs and cross-reference lingering mysteries from past seasons — especially those left dangling in Season 5’s finale, which wrapped in late 2025.

Season 5, adapted from Herron’s London Rules, ended with Diana Taverner finally achieving her long-coveted power play, while River Cartwright — portrayed by Jack Lowden — walked away from Slough House, leaving viewers wondering if he’d ever return. Now, with Season 6’s dual-novel structure, those threads won’t just be picked up — they’ll be rewoven into something darker, more personal.

Behind the Scenes: A Leadership Transition

The departure of original showrunner Will Smith after Season 5 marked a turning point. In an October 2024 interview with Deadline, Smith said he felt Season 5 resolved key arcs that had been building since Season 1. "It’s time to pass the torch," he said, not with resignation, but with confidence in the team’s next phase.

Enter Ben Vanstone, who’s now steering Season 7’s development. Vanstone, known for his work on Bodyguard and The Salisbury Poisonings, brings a sharper, more claustrophobic tone — perfect for the increasingly paranoid world of British intelligence. Meanwhile, director Adam Randall, who helmed Season 4’s tense showdown with Hugo Weaving’s Frank Harkness, is back to direct Season 6. His return signals continuity — even as the show evolves.

Production remains anchored in the UK, with See-Saw Films — the London-based powerhouse behind The King’s Speech and Top of the Lake — handling the gritty, atmospheric visuals that define the series. The crew’s attention to detail, from the dingy Slough House office to the rain-slicked streets of Westminster, has become a character in itself.

The Cast: Aging, Adapting, and Still Standing

At 66, Oldman’s Jackson Lamb — a chain-smoking, whiskey-swilling, brutally brilliant mess of a spy chief — feels more alive than ever. His performance isn’t just acting; it’s an accumulation of years, grudges, and secrets. The show leans into his age, making Lamb’s exhaustion feel earned, not just scripted. Supporting him are Kadiff Kirwan as the hilariously out-of-his-depth Roddy Ho, Dustin Demri-Burns as the perpetually anxious David Cartwright, and Saskia Reeves as Catherine Standish, whose quiet authority has become one of the show’s most compelling anchors.

And while Lowden’s River Cartwright may have walked away, his absence looms large. The show has hinted he’ll return — but not as the idealistic rookie we met in Season 1. He’s changed. So have they all.

What’s Next? The Road to Season 7

With Season 7 filming slated for late October 2025, the timeline is tight — but not unprecedented. Apple TV+ has quietly built one of the most consistent production schedules in streaming: Season 1 (2022), Season 2 (2023), Season 3 (2023), Season 4 (2024), Season 5 (2025), Season 6 (2026), Season 7 (2027). That’s a new season nearly every year, with minimal gaps.

And the source material? It’s not running dry. Herron released his ninth Slough House novel, Bad Actors, in January 2025 — just weeks before Oldman confirmed Season 6’s wrap. That’s more than enough fuel for seasons to come. The books are now a decade deep, and the TV adaptation is catching up — not just telling stories, but building a mythos.

Why This Matters

Slow Horses isn’t just another spy show. It’s a slow-burn character study disguised as a thriller. Where James Bond flies to exotic locales, Lamb’s team investigates bureaucratic rot in a leaky London basement. Where other series chase spectacle, Slow Horses finds tension in silence — in a half-empty mug of tea, a paused phone call, a too-long stare.

Its success lies in its refusal to rush. Even as streaming giants churn out content, this show takes its time. And that patience is why fans are willing to wait until Fall 2026 for Season 6. Because when it drops, it won’t just be a new season — it’ll be the next chapter in one of television’s most quietly brilliant sagas.