Gary Oldman has teased a more protective side to Jackson Lamb in ‘Slow Horses’ season 6, revealing that the famously abrasive MI5 spymaster will find himself increasingly concerned for the safety of his team when Slough House becomes the target of a deadly assassination plot.
Speaking during a virtual press conference for the upcoming season, Oldman discussed returning to one of television’s most beloved characters, the surprise return of Olivia Cooke’s Sid Baker, working with newcomer Lenny Rush, and the complicated relationship between Lamb and River Cartwright.
Season 6 sees the usually overlooked residents of Slough House suddenly become targets. Two former Slow Horses are killed in what initially appear to be unrelated accidents, with one apparently burned to death and another drowning after falling from a boat. However, Lamb soon realises that neither death was accidental.
Instead, the former agents are connected to a hit list, putting the remaining Slow Horses in danger.
“Lamb gives the Slow Horses a hard time,” Oldman explained, “but underneath all of that, he’s incredibly loyal.”
With the threat becoming increasingly personal, Lamb sends his team to a safe house and orders them to go dark while he attempts to uncover who is behind the killings. According to Oldman, the crisis allows audiences to see a different dimension of the character.
“You do see a more protective, more fatherly figure,” he said of Lamb in Season 6.
That protective instinct is particularly significant for a character whose preferred method of showing affection is generally to insult someone until they consider a career change. Yet beneath Lamb’s hostility, Oldman sees genuine loyalty towards his team.
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Olivia Cooke Returns as Sid Baker
One of the biggest talking points surrounding Season 6 is the return of Olivia Cooke as Sid Baker.
Sid was believed to have been killed earlier in the series, although rumours of her survival had circulated among fans. Oldman revealed that even the cast were not always certain about whether Sid would eventually return.
“For the longest time, we thought that Sid was dead,” Oldman said, explaining that rumours eventually began circulating about her possible comeback.
The actor was particularly pleased to see Cooke return, noting how much the production had enjoyed her work in the show’s first season.
Oldman also revealed an important part of Sid’s history: she was never truly one of MI5’s rejects. Instead, she had been deliberately placed at Slough House as a plant.
“Lamb always had great respect for Sid,” Oldman said, describing her as a “really good agent” and explaining that she was “put there specifically.”
However, viewers should not necessarily expect Sid to simply walk back into Slough House as though nothing happened. Oldman noted that she does not directly reintegrate into the team’s operations during the season.
Lenny Rush Gives Jackson Lamb a New Challenge
Season 6 also introduces a new dynamic through Lenny Rush, whose character becomes crucial to solving the mystery.
Oldman described Rush as key to Lamb’s investigation, with the veteran spy quickly recognising that the newcomer could hold the answer to the season’s central mystery. The problem is that Lamb has very little patience for him.
Their relationship is combative, but there is a grudging respect underneath it. Rush’s character is capable of giving Lamb as good as he gets, making him an unexpectedly formidable challenge for the notoriously intimidating agent.
The situation effectively forces Lamb into an unwanted babysitting role.
“He’s a necessary evil,” Oldman said of the character, describing the dynamic as an interesting one for Lamb.
It is another way in which Season 6 appears to push Lamb beyond his familiar comfort zone, placing him in a position where protecting people and solving the mystery become intertwined.
Gary Oldman Can “Switch” Jackson Lamb On Instantly
After six seasons of playing Jackson Lamb, Oldman admitted that the character has become deeply embedded in him.
While he joked about not smelling like Lamb despite the character’s famously dishevelled appearance, Oldman explained that playing the role for so long means Lamb is now almost instinctive.
“You can sort of switch him on now,” he said.
Indeed, Oldman said he could play Lamb “in an instant”, describing the experience as carrying the character’s “DNA” around with him.
That does not mean the actor has adopted all of Lamb’s less appealing qualities, however. Oldman described himself as considerably softer and more conflict-averse than his character, who has absolutely no filter and appears to enjoy confrontation.
“I don’t want confrontation,” Oldman explained, adding that he does not want to make people feel uncomfortable or “less than”, whereas Lamb can take pleasure in doing precisely that.
Why Does ‘Slow Horses’ Keep Getting Better?
With Slow Horses continuing to attract new viewers rather than losing momentum, Oldman believes the show’s success comes partly from its ability to turn the traditional spy genre upside down.
Instead of presenting audiences with glamorous spies, Aston Martins and casino-set adventures, the series focuses on deeply flawed people dealing with recognisable problems.
“They’re spies,” Oldman said, but they are also people dealing with mortgages, divorce, addiction, relationships and custody arrangements.
That relatability, combined with strong characters and consistently high-quality writing, has helped audiences become invested in the world of Slough House.
Oldman also pointed to the show’s release schedule as an important factor. Rather than leaving audiences waiting years between seasons, the series has maintained a relatively consistent cycle, helping viewers stay connected with its characters.
And with source material from Mick Herron’s novels providing a strong template, Oldman believes the series has been able to maintain its quality without losing sight of what made audiences fall in love with it.
“We have a wonderful template, which is the books,” he said, noting that this helps ensure the show does not suddenly “jump the shark.”
Lamb and River’s Complicated Bond
Oldman also reflected on the relationship between Lamb and River Cartwright, describing it as complicated by Lamb’s longstanding hatred of River’s grandfather, David Cartwright.
Despite that history, Lamb recognises something in River and sees genuine potential in him.
“He sees the potential of what he’s good at,” Oldman said, adding that Lamb believes River is actually good at the job.
For Oldman, there is essentially a father-son dynamic between the pair. Lamb may criticise River relentlessly, but his behaviour is ultimately rooted in a sense of loyalty and protection.
Oldman also offered his own interpretation of why River ended up at Slough House. In his view, Lamb understands that River was set up and was not sent there because he was a bad agent.
“He’s not a reject. He’s not a fuck up,” Oldman said, before acknowledging that River can sometimes become overenthusiastic and get ahead of himself.
That belief in River’s potential adds another layer to their already complicated relationship, and helps explain why Lamb remains so invested in the younger agent’s fate.
‘Slow Horses’ Season 6 will premiere on Apple TV on September 16 and will air new episodes weekly every Wednesday through October 21, 2026, continuing the story of Jackson Lamb and his dysfunctional team of MI5 agents.
