A host of new faces are joining the cast of Slow Horses for season seven, including Downton Abbey actress Tuppence Middleton. 

The Emmy-winning Apple TV series stars Sir Gary Oldman as Jackson Lamb, the cantankerous leader of a disgraced team of MI5 agents whose career-ending mistakes landed them in Slough House, the dumping ground of MI5.

In the latest season, which concludes on Wednesday, the Slow Horses find themselves on the run after former members of their team start turning up dead. Jackson Lamb is determined to uncover why his spies are being killed off one by one by two mysterious assassins: Jane (MyAnna Buring) and Jim (Kyle Soller).

Joining Tuppence in season seven are Varada Sethu (The Other Bennet Sister, Andor), Ethan Moorhouse (The Moment, Ludwig), Merab Ninidze (Homeland, The Courier) and Joshua McGuire (The Gold, Anatomy of a Scandal). Meanwhile, James Callis returns as Claude Whelan, the former MI5 First Desk.

The upcoming seventh season, based on the Bad Actors novel in Mick Herron's Slough House book series, follows Jackson Lamb and his Slow Horses on the hunt to find and neutralise a mole at the heart of the British Government before they can bring down the state.

Gary Oldman stars as Jackson Lamb in Slow Horses

While Gary Oldman's return as Jackson Lamb in season seven is confirmed, the rest of the returning cast has yet to be revealed. Looks like we'll have to wait and see who makes it out of season six alive!

Season six concludes on Wednesday

Season six sees Jackson Lamb and the Slow Horses determined to get to the bottom of why former members of their team are being killed off. Meanwhile, Diana Taverner (Kristin Scott Thomas) finds herself paying the price for her off-the-books deal with Peter Judd (Samuel West).

Ahead of the season six premiere, Saskia Reeves, who plays Catherine Standish, revealed that her character's shocking discovery about the death of her old boss, Charles Partner, takes her on a "dangerous" journey. 

In season six, the Slow Horses find themselves on the run after former members of their team start turning up dead

"It throws Cathrine completely and she is now actually on a very dangerous journey," the actress told HELLO! at the BAFTA Tea Party in Los Angeles on September, 13 2026.

"We will have to see if she can hold herself together – I really hope she can hold herself together."

Slow Horses is available to stream on Apple TV. Season six concludes on 21 Wednesday October 2026.