Slow Horses Season 6 Episode 1 Recap: Someone Is Hunting the Slow Horses

Warning: Major spoilers for Slow Horses Season 6, Episode 1.

Slow Horses Season 6 Episode 1 is back in familiar territory: murder, MI5 secrets, Jackson Lamb unbathed and flinging insults , and a mystery that quickly becomes very personal for Slough House. Apparently being banished to the house is no longer the worst thing that can happen to an MI5 agent.

You can also be erased from the system. Or murdered.

This darkly funny espionage drama follows a team of British intelligence agents who serve in a dumping ground department of MI5 due to their career-ending mistakes. Led by their brilliant but irascible leader, the notorious Jackson Lamb (Academy Award winner Sir Gary Oldman), they navigate the espionage world’s smoke and mirrors to defend England from sinister forces.

For anyone new to the series, the “Slow Horses” are disgraced or sidelined MI5 agents dumped at Slough House, the service’s administrative purgatory. They are supposed to spend their careers doing miserable work until they finally quit. Instead, they repeatedly save Britain. Their boss is Jackson Lamb (Sir Gary Oldman), a brilliant former field agent disguised as a man who appears to have spent several years sleeping in the same coat. He drinks, smokes, insults everyone around him and treats personal hygiene as an unreasonable government intrusion. And somehow, he is usually the smartest person in the room.

Season 5 ended with Lamb’s misfits helping stop another terrorist plot against London, while Diana Taverner (Kristin Scott Thomas) finally ascended to First Desk. Season 6 opens with Taverner firmly in charge, River Cartwright (Jack Lowden) grieving his grandfather and someone apparently cleaning up the Slow Horses — past and present.

Struan Loy Is Back — Briefly

The premiere begins with a wonderfully Slow Horses fake-out. A karate instructor lectures his class about muscle memory and how his secret-service training taught him the importance of instinct when under attack. The camera pulls back. His students are children. The instructor is Struan Loy (Paul Higgins), one of the original Slow Horses from Season 1. Struan now appears to be supplementing his karate income by promoting another entrepreneurial masterstroke: converting shipping containers into homes. His big selling point? They’re stackable. Later, Struan returns to his own shipping-container home and finds two strangers waiting for him. Jim (Kyle Soller) and Jane (MyAnna Buring) claim to be interested in his housing business. For a few moments Struan thinks he may finally have investors. He does not. Jane brutally attacks him and breaks his arm. Jim pours alcohol across the floor, they set the container on fire and lock Struan inside. His screams eventually stop.

Suddenly that speech about muscle memory isn’t funny anymore.

Welcome Back to Slough House

J.K. Coe (Tom Brooke) arrives at the familiar shabby building and hears someone coming down the stairs. Naturally, he grabs a keyboard and smashes the stranger in the face. Repeatedly.

Roddy Ho (Christopher Chung) and Shirley Dander (Aimee-Ffion Edwards) arrive, followed by Jackson Lamb. The bloody stranger turns out to be an estate agent. Coe thought he had a gun. Close enough. Catherine Standish (Saskia Reeves) soon arrives and discovers another problem: nobody at Slough House has been paid. Even worse, Roddy discovers that Slough House has disappeared from MI5’s computer system. Names. Service histories. Operational records. Payroll. Gone. Lamb’s response to not being paid is entirely predictable. He goes on strike.

Apparently patriotism has its limits, and Jackson Lamb’s limit is payday.

River Prepares to Say Goodbye

At Regent’s Park, Taverner is overseeing arrangements for the funeral of River’s grandfather, David Cartwright (Jonathan Pryce), the legendary former MI5 operative known as the Old Bastard. There will be security, Dogs stationed around the church and an approved order of service — all of which feels a little clinical to a grandson who has barely begun grieving. River has little patience for Taverner’s bureaucracy, although she eventually drops the First Desk persona long enough to tell him, “I really am sorry for your loss.” After River leaves, Taverner learns that former Slow Horse Struan Loy is dead. The coroner has ruled it an accident, and she decides there is no reason to inform Lamb. That decision is going to age badly.

The Park Has Visitors

Meanwhile, Taverner is adjusting nicely to life as First Desk. Among a group touring the Park are media mogul Damien Cantor (Harry Lloyd) and an old irritant, former politician Peter Judd (Samuel West). Judd congratulates Diana on wearing the crown so well. She reminds him she’s surprised he managed to get security clearance. Some relationships never change. The visitors watch footage of an MI5 raid on a Russian-backed bot farm before Taverner receives an urgent summons: “Code Vulcan.” Vulcan, it turns out, is her assistant’s cat. It’s merely an excuse to escape the tour. I like Diana as First Desk already.

Slough House Has Been Erased

River returns to Slough House and asks the obvious question: if nobody has been paid, why is everyone still there? Roddy has the answer. None of them has anywhere else to go. River doesn’t really either. He sits alone looking through photographs of his grandfather and calls his mother, Isobel. He reaches voicemail and asks her to let him know whether she’s coming to the funeral. Meanwhile, Catherine goes to the Park to investigate the payroll problem and discovers something far more troubling. The disappearance of Slough House from MI5’s database wasn’t an administrative mistake. The order came from the top.

Lamb Smells Something Wrong

Lamb is enjoying a meal and bottle of wine when an MI5 employee tells him Struan burned to death inside a shipping container. At first, Lamb is unmoved. Struan, he explains, divided opinion. Some people thought he was a total waste of space. Others thought that assessment was too generous. Classic Lamb. Then he notices something in the report. Struan had a broken arm. One broken arm shouldn’t have prevented him from opening an unlocked shipping-container door. Suddenly Lamb is interested. He takes the file — describing it as something to read on the toilet — and leaves his colleague with the restaurant bill.

Why Didn’t Struan Open the Door?

Lamb takes River to the burned-out container. River is still angry that Lamb hasn’t kept his promise to help him return to the Park. Lamb decides what River really needs is grief counseling, Jackson Lamb-style. He mocks him. River kicks the container.

“Better?”

“No.”

Therapy over.

Then Lamb closes River inside and tells him to open the door one-handed. River does it easily. So why couldn’t Struan? Lamb finds a piece of wood and demonstrates how it could have been slid through the exterior handles, trapping Struan inside. This wasn’t an accident. Lamb immediately tells Roddy to check on every former Slow Horse. And he’s already too late.

Someone Is Killing Slow Horses

At a peaceful houseboat, an older woman is attacked by the same couple who killed Struan. Jim and Jane force her underwater until she stops struggling. Another former Slow Horse is dead. As the killers walk away, they discuss their next target. Then comes the line that changes everything: “Who the fuck calls their child River?” River Cartwright is next.

Goodbye to the Old Bastard

Before the funeral, River remembers his grandfather’s final days. Jonathan Pryce gets one last heartbreaking scene as David talks about how much he misses his wife and tells River how much he will miss him. “My boy.” It’s quiet and devastating. For a series that can move from murder to flatulence within minutes, Slow Horses remains remarkably good at grief. And right on cue, Lamb and Catherine share a cab to the funeral. Lamb eats. Lamb drinks. Lamb burps. Lamb farts. Catherine questions whether he should be drinking during the service, while Lamb suggests that perhaps this is simply what grief looks like for him. And yes, even the flatulence is apparently part of the performance. Gary Oldman has revealed just how seriously he takes this particular Jackson Lamb character trait: “I’ve even sent emails about the flatulence.”

Apparently, there are no gratuitous farts at Slough House. Even Lamb’s gas has to serve the story. At the church, River faces an unusual problem: how do you eulogize one of Britain’s great spies when almost everyone in attendance is supposed to believe he worked for the Department of Transport? River gamely praises his grandfather’s devotion to transportation. Cars. Buses. Trains. Planes. Lamb starts laughing. Then he cannot stop. It’s horribly inappropriate and completely understandable. River is trying to honor his grandfather while maintaining the fiction of his life; Lamb knows exactly who they’re really burying. Afterward, Lamb confronts Taverner about Slough House disappearing from MI5’s systems. She calls it a database glitch. Lamb doesn’t believe her.

Neither do I.

Frank Harkness Returns

Then River spots someone watching from a distance. His father. Frank Harkness (Hugo Weaving). River confronts him and demands to know why he’s there and who he’s working with now. Frank says he came to watch his son bury his grandfather. Then he punches River. And because apparently hitting your grieving son at his grandfather’s funeral isn’t enough, Frank asks whether River’s mother bothered to show up. She didn’t.

“Pretty bad day all around.” River loses it, jumping onto Frank’s car as he drives away before eventually being thrown off.

Jackson Lamb watches the whole disaster unfold.

My Review

This is exactly the kind of Slow Horses premiere I wanted. Season 6 starts deceptively small: a ridiculous karate class, a shipping-container salesman, a missing paycheck and a funeral. Then it reveals that none of those things are small at all. The episode keeps returning to one unsettling idea: erasure. Struan is murdered. Another former Slow Horse is killed. Slough House has been digitally erased. David Cartwright is being laid to rest beneath the fictional identity he maintained for decades. And River himself seems increasingly untethered.

Meanwhile, Lamb does what Lamb always does. He insults everyone, drinks, refuses to work because he hasn’t been paid and sticks someone else with his lunch bill. But beneath all of that, he notices the one detail everyone else missed: Struan should have been able to open that door. That’s what makes Gary Oldman’s Jackson Lamb such a great character. The filth, insults and flatulence are almost camouflage for an extraordinarily observant intelligence officer. And somebody has just started killing his Slow Horses.

The biggest question isn’t simply who Jim and Jane are working for. It’s why Slough House has been erased from MI5’s records at exactly the same time its former agents are being eliminated. Coincidence? This is Slow Horses. There are no coincidences. Only secrets, grudges, cover-ups, and Jackson Lamb’s dirty (and likely smelly) coat.

Questions I’m Still Asking

Who ordered Slough House erased from MI5’s database?

What does Diana Taverner know?

Who hired Jim and Jane?

Why is River their next target?

And what is Frank Harkness doing back in London?

Do you have any theories or ideas about what could be going on here?

Slow Horses Season 6 premieres September 16, 2026 on Apple TV.