Slow Horses Season 5 Is A Laugh-Out-Loud Triumph — The Series’ Best Yet
After season 4’s emotional surge, the new run snaps back—cooler, tighter, and calibrated for momentum.
Apple TV+ has been quietly building a spy hit with Slow Horses, and things really popped with last year’s season 4. It was not just more people finally catching on; the show dug into River’s messy family history, introduced his villainous dad Frank, and faced down his grandfather’s worsening dementia. Even Mick Herron, who wrote the novels, has said season 4 is his favorite. So yeah, expectations for season 5 are high. Good news: it delivers. Big time.
Where season 5 sets its sights
This run gets pitched as Roddy Ho’s season, and that’s true enough: he kicks off a lot of what happens. After Roddy is nearly flattened by a truck, Shirley clocks that he suddenly has a very glamorous new girlfriend, which does not pass the smell test. On the other side of London, there’s a seemingly random shooting. These things do not look connected. Shirley, being a student of how Slow Horses actually works, assumes they are.
From there, London goes sideways. A string of increasingly odd incidents strike the city right as a bruising mayoral race heats up. Lamb wants his crew on the case, but that only flies if Diana Taverner and the Park (MI5 HQ) do not slam the brakes. The season moves with purpose: clean, efficient plotting; hints dropped with just the right timing; the larger mystery unfurling without wasting your weekend.
Politics takes the wheel (and it works)
The election backdrop pulls politics into the foreground more than usual. The big twist: the season draws on Herron’s 2018 novel London Rules, but the show’s take feels very now. A lot of that comes down to showrunner Will Smith (the one from The Thick of It and Veep, not that other Will Smith). He knows how to punch up the absurdity and still make the machinery feel plausible.
Enter Nick Mohammed and Christopher Villiers as rival party leaders Zahar Jaffrey and Dennis Gimball. Both are dialed up just enough to be satirical without turning into cartoons. They are funny, pointed, and unfortunately recognizable.
Spy craft, office cringe, and actual belly laughs
This is not the season that reinvents espionage on TV, and that is not the job here. The appeal has always been the blend: sturdy spy thrills plus a dry, nasty sense of humor — Smiley or Bond colliding with an office comedy. This time, that balance is the tightest it has ever been.
Yes, Roddy’s front and center, and Christopher Chung leans into the character’s ridiculous brilliance. He bounces off the very serious set of Kristin Scott Thomas’s Diana Taverner and Ruth Bradley’s Emma Flyte in ways that feel designed to annoy both of them, which is delightful. But the big surprise is how well the laughs spread around. Pairing Jack Lowden’s River with Tom Burke’s JK Coe is inspired; they get a midseason sequence that might be the funniest thing the show has done. Book readers will clock it the second it starts.
James Callis continues to be a killer addition, with the chronically over-promoted Claude Whelan getting more shading and more to do. And Gary Oldman is still having the time of his life as Lamb. One gag in particular has already been teased everywhere — let’s just say the show finds a way to turn flatulence into a tactical advantage.
Season 5 is the best Slow Horses run yet — sharper, funnier, and bold enough to swing for a couple of wild tonal choices that absolutely land.
The heart under the grime
Amid all the chaos, the show remembers to care. Aimee-Ffion Edwards gives Shirley real weight as she quietly processes Marcus’s death from the end of season 4. It is mostly under the surface, but you feel it. She also gets to tear through some chunky action beats, which helps the season’s momentum.
Speaking of momentum: the longer-running arcs do not stall. They are not the headline early on, but by the finale you can feel the show has made tangible moves forward. If you worried the post-season-4 comedown would be rough, you can relax.
The Will Smith era bows out
This is the last season with Will Smith steering the adaptation, and he leaves it in absurdly good shape. Slow Horses has joined the small group of Apple TV+ titles that broke through beyond critics — think Ted Lasso and Severance — and that is not just because Herron’s books are strong. The show has been reliably released, consistently well-cast, and cleanly written and directed. Pulling all that together across five seasons is no small feat. Smith deserves the ovation.
Looking ahead to season 6
Season 6 is already on deck. Every year there is a little voice that says: this could be the dud. It has not happened yet. Whether that was all Smith’s steady hand or the show’s DNA, we will find out. Ideally, the handoff to new creatives will be so smooth that no one can tell it happened.
Standouts this season
- Christopher Chung as Roddy Ho — the catalyst for the chaos, and very much in his comedic sweet spot.
- Aimee-Ffion Edwards as Shirley Dander — grieving Marcus while running headlong into the action.
- Jack Lowden and Tom Burke as River Cartwright and JK Coe — an odd-couple pairing that pays off with one of the show’s funniest sequences.
- Kristin Scott Thomas and Ruth Bradley as Diana Taverner and Emma Flyte — the straight faces to Roddy’s nonsense.
- James Callis as Claude Whelan — the comically over-promoted operator who finally gets some depth.
- Gary Oldman as Jackson Lamb — still a menace, now with a much-teased gag that turns flatulence into a weapon.
- Nick Mohammed and Christopher Villiers as Zahar Jaffrey and Dennis Gimball — rival party leaders who make the political satire sting.
The verdict and the date
I gasped, I laughed out loud, and there is a scene so tonally audacious I could not believe they went for it — and they nailed it. For me, season 5 is the high-water mark so far. Not bad for a squad of professional screwups.
Slow Horses season 5 premieres September 25, 2025 on Apple TV+.