‘Slow Horses’ Season 5 Review: Unorthodox, Unhinged, Unmissable

As solid as the book series it’s based on —and just as effective in keeping up its annual rhythm— Slow Horses returns with a fifth season where our band of second-rate spies once again throw the world into chaos, only to prove they’re the only ones who can fix it. “Our methods are unorthodox,” one of them quips while saving the day. And unorthodox they are. With a drunken boss (Gary Oldman) who never bathes and terrorizes half of London with his flatulence, plus a ragtag bunch of misfits, screwups, and oddballs, the Slough House agents are back at it in another brisk, entertaining season.

By now, the concept needs little introduction, so let’s dive straight in. The season opens with a violent bang: an armed man opens fire in a crowded London street, killing eleven in a terrorist attack, before he himself is gunned down. As the chaos unfolds, someone tries to kill Roddy Ho (Christopher Chung), the cocky and insufferable tech guy of Slough House —and nobody can make sense of the connection. Soon, Ho finds himself entangled in the mess, when it turns out that a supposed “romantic conquest” has been manipulating him all along. Naturally, he insists it was the other way around.

From there, a string of incidents spreads across the city —less brutal than the opening massacre, but still disruptive, ranging from traffic chaos to flaming trash bins to dead penguins— hinting at what looks like a terrorist plot driven by an Arab group. Unsurprisingly, the timing coincides with the upcoming London mayoral election, pitting the “progressive” Zafar Jaffrey (Nick Mohammed, Ted Lasso) against far-right candidate Dennis Gimball (Christopher Villiers).

As usual, the “slow horses” get sidelined —Ho is even partly blamed and questioned— but, true to form, they scramble back into action, using their wits to solve what MI5’s official leadership, led by the sharp Diana Taverner (Kristin Scott Thomas) and the hapless Claude Whelan (James Callis), can’t quite piece together. That means more threats, chases, money trails, and political stakes.

Unlike last season, this one —based on Mick Herron’s London Rules, the fifth book in the saga— doesn’t look backward into Britain’s espionage past or delve much into the characters’ histories, something explored previously through River Cartwright (Jack Lowden) and his grandfather (Jonathan Pryce). Here, while there are references to the darker corners of Britain’s colonial spycraft, the emphasis leans even further toward humor. It works brilliantly when delivered through Jackson Lamb (Oldman), but feels thinner when shifted onto some of the supporting characters.

Humor is, no doubt, a key ingredient in the show’s success, but at times Will Smith’s scripts —this season marks his final run as showrunner— try too hard, slipping in cheeky jokes where they don’t belong. That’s especially true of Roddy Ho, whom Chung plays with gusto, though the character risks becoming more gag than contribution to the story.

Even so, the series remains excellent, giving longtime espionage fans a taste of classic John le Carré intrigue (and the films and series inspired by his work), while layering in a sharp, contemporary edge. Slow Horses has long since abandoned plausibility —Lamb finds solutions with the resourcefulness of the filthiest X-Man imaginable— but that doesn’t make it any less clever or compelling. What makes it work is not just Herron’s source material, but also a squad of pathetic yet oddly endearing losers who always manage to pull things off in the most unorthodox ways possible.