Slow Horses series 4 review: Swaggering and truly distinctive in the way that very few shows are

Since it debuted in 2022, Apple TV+’s Slow Horses has produced three excellent seasons. The fourth premieres this week, just nine months after the last series finale. With this level of output, you’d be forgiven for assuming the quality would vary wildly – like a restaurant pushing out half-baked soufflés for the braying dinner crowd – and yet Slow Horses has become that most wondrous of things: a truly reliable televisual crowd-pleaser.

This latest chapter picks up where the previous one left off: David Cartwright (Jonathan Pryce), the grandfather of Slough House resident River (Jack Lowden), and a former bigwig in MI5, is gradually succumbing to senility. Can the old man still discern friend from foe? And, if not, who is the guy, claiming to be his grandson, who’s now lying in the bathtub with his head blown off? And while the Cartwrights face off against a shadowy enemy, a bomb at a shopping centre sends the security services – from second desk chief Diana Taverner (Kristin Scott Thomas) to gnarled outcast Jackson Lamb (Gary Oldman) – spinning. What links a suicide bomber in London with a mercenary commune in rural France?

After the carnage of the third season’s shoot ’em up finale (which tested the laws of plausibility that Slow Horses tends to bend but not break), this fourth season is a return to the territory covered in the show’s sophomore outing. Old wounds, reopening. And at the centre of it all is Oldman’s Lamb (“A man who looks like he gropes people on buses,” according to new head dog Emma Flyte, played by Ruth Bradley). With each season of Slow Horses, Oldman appears caked in another layer of grime. It is a role that the actor has said he wants to play “for the long run”. And, after all, why not? He is rarely tasked with stunt work (beyond crashing a black cab) and instead gets to consume various unhealthy snack items whilst collecting a fat paycheque and numerous accolades.

Which is not to underplay the performance. Oldman’s Lamb is impeccable – but we’ve known that for a while. Lowden, too, has matured into the role, positioning River somewhere between James Bond and Johnny English on the scale of spy competence. Pryce will get plaudits for his depiction of the paranoia of dementia, but it is new addition James Callis, as incoming first desk Claude Whelan, who proves the most effective foil to the series regulars. It is as good a depiction of slippery, half-confident upper management as you’re likely to see. And it plays into one of Slow Horses’ great strengths: its depiction of office politics.

Those dynamics (aided by the appearance of Joanna Scanlon in her patented role of administrative busybody) are slightly more coherent than the pan-European revenge saga. But at this point, Slow Horses is propelled by an internal logic, born of enormous self-confidence. The show feels swaggering and well-defined in the way that very few shows are. Whether it’s reprobate hacker Roddy (Christopher Chung) eating chicken nuggets or shrewd assistant Catherine Standish (Saskia Reeves) peeping through the crack of a door, the show is unified by a specific tone and aesthetic, one that is distinctly its own.

“I’ve dealt with men like Lamb before,” Flyte tells her boss. “I don’t think you have,” Tanner replies. On the face of it, there is little revolutionary about Slow Horses. And yet, over the course of four hastily assembled seasons, it has become something truly distinctive. The temptation to celebrate the show for Oldman’s central performance – as corpulent and corrupt as ever – belies its evolution into one of the most consistent, and consistently enjoyable, shows on TV.

This article has been amended to correct the name of Kristin Scott Thomas’s character Diana Taverner