“A bold new chapter”: What “unexpected” changes mean for Slow Horses’ “refreshed” series 6

Where do disgraced or failed spies go to die? Well, squander professionally? They go to pasture in Slough House, espionage purgatory for MI5 officers, of course. Yet fans of Apple TV's hit series, Slow Horses, will know that the East London dumping ground has become the forefront of unravelling international terrorist plots and inside betrayal. And now, our favourite exiles are back for a bold new chapter - and the refreshed series 6 is bringing some unexpected changes with it.

Based on two more of Mick Herron’s spy thriller novels, the new instalment is set to take us on quite the rollercoaster ride. The ruthless Diana Taverner (Kristin Scott Thomas) is finally the top dog of MI5's HQ The Park. And with a long-running and complex rivalry with the dishevelled, yet astute, Jackson Lamb (Gary Oldman) - it isn't going to be easy for for our downtrodden spies who become competitors in what Apple TV describes as “a fatally high-stakes game of retaliation and revenge.”

With a new lead writer, a fresh-faced cast member and a change of pace for our Slow Horses in store, here’s everything you need to know about the sixth series ahead of its release this September.

What is Slow Horses about?

Based on Mick Herron’s award-winning Slough House book series, the series centres around the divide between Slough House, the home of exiled spies who have committed career-ending mistakes, and The Park, otherwise known as MI5 HQ. However, we quickly discover the banished intelligence hold the key to taking down international terrorists and inside traitors. Here’s a whistle-stop tour of the last five series.

Series one introduces us to River Cartwright (Jack Lowden) who monumentally messes up a training mission (or, so it seems) and is exiled to Slough House. His miserable boss, Jackson Lamb (Gary Oldman) believes most of his "Slow Horses" will eventually leave out of boredom, but he couldn't be more wrong. Instead, River and the team help uncover MI5 boss Diana Taverner’s (Kristin Scott Thomas) secret gambit as she plants a dangerous false flag operation designed to make her team appear heroic. Meanwhile, another member of the team, Sid Baker (Olivia Cooke) is shot whilst surveilling a right-wing journalist.

Series two centres around the unravelling of Cold War secrets and an ongoing Russian operation. The drama kicks off with the death of a former MI5 agent on a bus, which leads River to the Cotswolds to go undercover. Elsewhere, a meeting with an Oligarch ends in blood-shed leading to a suspenseful race against time to stop a catastrophic incident.

In series three, which is based on the 2016 novel, Real Tigers, the action picks up in Istanbul, where a romantic affair takes a treacherous turn and the agents find themselves caught up in a conspiracy. The conspiracy threatens to expose a buried MI5 secret in London, and as they try to uncover the mystery, they find themselves in a lot of danger.

The next instalment is adapted from 2017’s Spook Street and picks up with a bomb detonating in a shopping centre, with a fraught race to find the mastermind behind the operation. It's an explosive start to a series that has a record number of huge revelations within it - particularly in regards to people's identities.

In series five, Libyan terrorist attacks send London into chaos and the resident tech nerd, Roody Ho (Christopher Chung) falls victim to a “honey trap” operation. In a high tense race, River saves the life of Claude Whelan (the then First-Desk) from a gunman - despite his service, Lamb refuses to let him go from Slough House. Meanwhile, Lamb outmanoeuvres the arrogant Whelan with a career-ending recording.

The finale left us with some serious questions, such as will Louisa Guy (Rosalind Eleazar), the much-loved agent return, to the band of misfits? And, will we learn more about Lamb’s harrowing past?

What will happen in Slow Horses series 6?

While Apple TV is doing its best to keep key plot details under wraps, we know that we'll find the Slow Horses on the run, and embroiled in a "fatally high-stakes game of retaliation and revenge" as the power-hungry Diana Taverner finally takes the throne as MI5 first-deck.

What changes will there be in Slow Horses series 6?

As we mentioned, series 6 is bringing some surprise changes with it, including a new cast member and writer. Here's the lowdown.

There's a new lead writer

Acclaimed screenwriter, Gaby Chiappe, is taking over from Will Smith, the award-winning executive producer of the last five series. Smith shared with Deadline that he felt it was the right time to depart, with storylines starting in series 1 rounding off in his last run. Now, he's handing over to screenwriter Gaby, who is well-known in the industry. She's the brains behind ITV's 2016 thriller, The Level, and has worked on the BBC's beloved detective drama, Shetland, where she was praised for her development of a hard-hitting storyline about rape. We can't wait to see what she brings to the Slow Horses' writing room.

Two books are being adapted

While all the episodes are adapted from Mick Herron's acclaimed "Slough House" series, each previous series has corresponded with one book. For example, series 1 was based on Slow Horses, series 2 was adapted fro, Dead Lions and series 3 took its story from Real Tigers. For the first time, the director, Adam Randall and co-executive, Chiappe, are adapting two novels at once - the 6th and 7th in the series called Joe Country and Slough House.

There's a new member of the Slow Horses

Ever the eclectic bunch, the rejects have recruited a new member, with BAFTA-winner Lenny Rush joining the cast. While we don’t yet know the details of his role, we predict the 17-year-old will bring plenty of humour to the world of espionage, particularly given that his performance in Daisy May Cooper’s Am I Being Unreasonable? earned him the BAFTA for Best Male Comedy Performance.

The Slow Horses are a little... busier

As if they aren't tied up enough stopping global terrorist plots and catching killers, they have another calamity on their hands - the Slough Horse cohort are on the run. After five series of scheming, the power-hungry Diana Taverner is finally promoted to “First Desk”, the Director General of MI5. which means they've got their work cut out more than ever. Taverner and Lamb have, to put it kindly, a tumultuous relationship qnd now she's at the top, she's ready to harness her power into vengeance.

Who’s in the cast of Slow Horses series 6?

The cast of Slow Horses series 6 includes:

• Kristin Scott Thomas (Four Weddings and a Funeral) as Diana Taverner
• Jack Lowden (Pride and Prejudice) as River Cartwright
• Saskia Reeves (Close My Eyes) as Catherine Standish
• Christopher Chung (Blitz) as Roody Ho
• Aimee-Ffion Edwards (The Revenge Club) as Shirley Dander
• Rosalind Eleazar (Missing You) as Louisa Guy
• Joanna Scanlan (Riot Women) as Moira Tregorian
• Samuel West (All Creatures Great and Small) as Peter Judd
• Ruth Bradley (In Her Skin) as Emma Flyte
• Tom Brooke (Empire of Light) as J. K. Coe
• Jonathan Pryce (The Two Popes) as David Cartwright
• Hugo Weaving (The Matrix) as Frank Harkness
• Lenny Rush

How can I watch Slow Horses series 6?


Slow Horses series 6 will premiere globally on Apple TV on Wednesday 16^th September with the first episode. The remaining episodes will air weekly until 21^st October. If you can't wait for all the gripping drama, you can catch-up on all the first five series now on Apple TV.

What other spy thrillers can I watch now?

If you’re after another brilliant spy thriller, we’d recommend Secret Service, which stars Gemma Arterton as Kate Henderson, a senior MI6 agent masquerading as an ordinary member of the civil service who soon finds herself tangled up in a web of destruction. All episodes of Secret Service are available to stream now on ITV. For an equally suspenseful watch, we'd suggest Unfamiliar, which follows former Federal Intelligence Service (BND) agent and her family who are forced to go on the run when their secret Berlin hideaway known as "The Nest" is exposed. You can watch all episodes of Unfamiliar now on Netflix.