Olivia Cooke Returns as Sid Baker in Slow Horses Season 6

Apple TV has confirmed a major return for the sixth season of Slow Horses: Olivia Cooke is reprising her role as Sid Baker in the acclaimed espionage thriller.

The new season, which brings back Sir Gary Oldman as Jackson Lamb, the irritable leader of a disgraced group of MI5 agents, premieres on Wednesday, 16 September.

A newly released trailer offers the first look at the latest chapter, with Jackson facing a deadly mystery as members of his team are seemingly being picked off one by one. Two unidentified attackers, played by MyAnna Buring and Kyle Soller, appear to be behind the killings.

The trailer also delivers the biggest surprise for longtime viewers. Near the end, River Cartwright is left stunned when he sees Sid standing at the top of a staircase.

Sid Baker is back

Sid was introduced in the first season and appeared to have been killed after being shot in the head. Her fate, however, was never completely settled.

Later, Roddy Ho discovered that Sid’s records had mysteriously disappeared, raising the possibility that she had survived. The season six trailer now confirms that Olivia Cooke will return to the series as Sid.

Her comeback is one of the most intriguing developments ahead of the new season, particularly given the circumstances surrounding her apparent death.

What happens in season six?

Season six draws from Joe Country and Slough House, the sixth and seventh novels in Mick Herron’s award-winning Slough House series, which won the CWA Gold Dagger Award.

The new episodes find the Slow Horses on the run after being targeted by two assailants.

The official synopsis describes the team as being caught up in a “fatally high-stakes game of retaliation and revenge” after MI5’s Diana Taverner becomes involved.

Kristin Scott Thomas returns as Taverner, whose position has also changed following the events of season five.

Christopher Chung, who plays tech expert Roddy Ho, previously teased the connection between the two seasons when speaking to HELLO!, saying there would be “a lot of crossover” from where the fifth season ended.

He also pointed to Taverner’s promotion to First Desk as one of the developments that would be particularly interesting to watch unfold in season six.

Who stars in season six?

Gary Oldman returns as Jackson Lamb, with Kristin Scott Thomas, Jack Lowden, Saskia Reeves, Christopher Chung, Aimee-Ffion Edwards, Rosalind Eleazar, Joanna Scanlan, Samuel West, Ruth Bradley, Tom Brooke, Jonathan Pryce and Hugo Weaving also reprising their roles.

BAFTA winner Lenny Rush joins the cast for the new season.

Olivia Cooke will also be back as Sid Baker, marking the character’s return after her presumed death in the show’s opening season.

When can you watch Slow Horses season six?

Slow Horses season six premieres on Wednesday, 16 September.

The first episode will be released on that date, with a new episode arriving each week through 21 October.