Seasons 3 and 4 have been shot back to back.

By Molly Moss

Published: Tuesday, 11 April 2023 at 12:00 am


We might still be waiting for Slow Horses season 3, but thoughts are already turning towards the fourth instalment, production on which is underway. 

Slow Horses season 4 was first announced in June 2022, when Apple TV Plus renewed the acclaimed spy drama for a further two runs.

Fans will be pleased to hear that plenty of familiar faces are set to star in the fourth chapter, with Gary Oldman set to return as intelligence officer Jackson Lamb, while new cast members include the likes of Hugo Weaving (The Lord of the Rings) and BAFTA winner Joanna Scanlan (After Love).

Ruth Bradley (Guilt) has also joined the season 4 cast along with Tom Brooke (Empire of Light) and James Callis (Battlestar Galactica).

The spy series revolves around a dysfunctional team of MI5 agents who have been exiled to MI5 dumping ground Slough House and has been a huge hit for Apple TV+.

So, what mysteries will be in store for the cast in season 4? Read on to find out.

Will there be a Slow Horses season 4?

Yes! It was confirmed back in June 2022 that the series would be returning for at least a third and a fourth season, and that the new runs would be shot back-to-back just as seasons 1 and 2 were.

There could be even more instalments on the horizon, with season one director James Hawes previously outlining his hopes for further seasons, telling Deadline that “there is every hope and intention that there will be another couple of seasons in the immediate future.”

Slow Horses season 4 release date speculation 

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Gary Oldman as Jackson Lamb in Slow Horses.
Apple

Seasons 1 and 2 were released in quick succession, after being shot back-to-back, with the first season landing in April 2022 and the second in December.

Seasons 3 and 4 have also been shot back-to-back, but this could mean a longer hiatus between seasons 2 and 3.

With seasons 3 and 4 announced in Summer 2022, and filming kicking off on the new instalments shortly after, it’s possible we could see season 3 landing in late 2023 and season 4 sometime in 2024.

Slow Horses season 4 cast

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Joanna Scanlan as Ma Larkin in ITV’s The Larkins
ITV

Gary Oldman will be back in the lead role as Jackson Lamb, while returns can also be expected for most of the ensemble, which includes Kristin Scott Thomas (Diana Taverner), Jack Lowden (River Cartwright), Saskia Reeves (Catherine Standish), Rosalind Eleazar (Louisa Guy), Christopher Chung (Roddy Ho), Aimee-Ffion Edwards (Shirley Dander), Kadiff Kirwan (Marcus Longridge), and Jonathan Pryce (David Cartwright).

Meanwhile, new cast members include Hugo Weaving (The Lord of the Rings), BAFTA winner Joanna Scanlan (After Love), Ruth Bradley (Guilt), Tom Brooke (Empire of Light) and James Callis (Battlestar Galactica).

Behind the camera, season 4 will be directed by Adam Randall (I See You).

Slow Horses season 4 plot: What could happen?

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Kristin Scott Thomas as Diana Taverner in Slow Horses season 2.
Apple TV+

A press release has revealed that the fourth instalment will “open with a bombing that detonates personal secrets, rocking the already unstable foundations of Slough House”.

Other than that, plot details for season 4 are currently pretty light on the ground, but we do know it will be based on Mick Herron’s novel Spook Street, the blurb for which reads: “Twenty years retired from the Intelligence Service, David Cartwright still knows where all the bones are buried. But when he forgets that secrets are supposed to stay hidden, there’s suddenly a target on his back.

“The ‘Old Bastard’ raised his grandson to be a hero, not a slow horse. Now, far from joining the myths and legends of Spook Street, River Cartwright is part of Jackson Lamb’s team of pen-pushing no-hopers at Slough House. Which doesn’t mean he won’t ditch everything and go rogue when his grandfather comes under threat.

“Lamb worked with Cartwright back in the day, and knows better than most that this is no innocent old man. So when a panic button raises the alarm at Intelligence Service HQ, it’s Lamb who’s called on to identify the body. And it’s Lamb who’ll do whatever’s necessary to protect an agent in peril.”

Is there a trailer for Slow Horses season 4?

Not yet, but watch this space!