Brilliant British Delight 'Slow Horses' Keeps Proving One of the Small Screen's Best-Ever Spy Thrillers

In gleaming news for streaming viewers, Mick Herron's Slough House novel series boasts 12 entries so far. In another ace development, several more of the British author's books have links to the world of veteran espionage agent Jackson Lamb. If you're already a fan of Slow Horses, you'll be thrilled. For newcomers, you'll feel the same after diving into this small-screen spy delight and binging your way through it as quickly as possible. Thankfully, all those tales on the page mean that the episodic thriller based on Herron's work has plenty more stories to draw upon in its future. Now up to its third brilliant season as a television series, long may its forward path continue.

Apple TV+ has clearly felt the same way since the program debuted in April 2022. In June the same year, the platform renewed Slow Horses for a third and fourth run before its second had even aired. That next chapter arrived that December and didn't disappoint. Neither does the latest and 2023's only batch of six episodes, this time taking its cues from Herron's Real Tigers — after season one used the novel Slow Horses as its basis, and season two did the same with Dead Lions — in charting the ins and outs of MI5's least-favourite department. Slough House is where the service rejects who can't be fired but aren't trusted to be proper operatives are sent to dwell in record-keeping drudgery, with Lamb (Gary Oldman, Oppenheimer) its happily cantankerous, seedy and shambolic head honcho.

Each season, Lamb and his team of losers, misfits and boozers — Mick Jagger's slinky earworm of a theme tune's words — find themselves immersed in another chaotic case that everyone above them wishes that they weren't. That said, Slow Horses isn't a formulaic procedural. Sharply written, directed and acted, and also immensely wryly funny, it's instead one of the best spy series to grace television. Each repeat go-around might feature Lamb's band of disgraced agents demonstrating that they're not the write-offs that the rest of the espionage field thinks — and often wants — them to be, but every season-long predicament is meticulously detailed, as are the series' characters. It's easy to see why all things Slough House have gone the television route, rather than following Bond, Bourne and Mission: Impossible into cinema: these are people and scenarios that benefit from spending as much time with as possible.

Slow Horses' astuteness, excellent cast and knack for comedy are all present in season three, which starts with two British intelligence officers in Istanbul. Sean Donovan (Ṣọpẹ́ Dìrísù, Gangs of London) and Alison Dunn (Katherine Waterston, Babylon) share a bed as well as the same outpost, but there's a shadow over their bliss: he's been tasked with investigating whether she's leaking classified information. The Bourne movies come to mind in early chases, but Lamb and his spooks are still the show's focus. Accordingly, when the fallout from the opening events touches Slough House, River Cartwright (Jack Lowden, The Gold), Catherine Standish (Saskia Reeves, Creation Stories), Louisa Guy (Rosalind Eleazar, Class of '09), Marcus Longridge (Kadiff Kirwan, This Way Up), Shirley Dander (Aimee-Ffion Edwards, Dreamland), Roddy Ho (Christopher Chung, Gods of Their Own Religion) and their boss — plus his boss Diana Taverner (Kristin Scott Thomas, Rebecca) — are thrust into a game of cat-and-mouse that revolves around secret documents.

In London, the situation hits home when one of the Slow Horses' own, the forever-loyal Standish, is abducted. The talented Cartwright again endeavours to illustrate why being banished to Slough House for a training mistake was MI5's error — and why caring about his team has always been one of his finest and most-reliable traits. This'd be a lesser show if Cartwright was simply a gleaming hero forced down the ladder for one false move and always excelling, however, and if Lamb's relentless cynicism about his team's highest flyer was just the bitterness of an old hand about an up-and-comer. Slow Horses doesn't ever throw around the terms in its opening song 'Strange Game' as insults, instead understanding that none of the agents on a slippery slope are perfect because no one is.

Indeed, Cartwright and company don't keep chasing a ghost of a chance to get out of spy purgatory solely out of pride, but also due to skill, tenacity and resilience. Lamb's team isn't kept in their place merely because of vendettas or politics — although both factor into the ongoing storyline — but also via struggles, troubles and flaws that are hardly uncommon. All of MI5's inflated egos, uncooperative attitudes, bad tempers, problem gamblers, substance abusers and recovering alcoholics haven't been banished to Slough House, either. While there's a sense of romance to every underdog tale about ragtag outsiders finding somewhere to fit in, Slow Horses is clear-eyed about an unassailable fact: often, all that separates the Lambs and Cartwrights from the Taverners and Spiders (aka The Great's Freddie Fox as James Webb, who has long loved lording his status over his former training rival) is however the cookie happens to crumble.

Season three adds extra emphasis to this truth by digging into Taverner's icy turf war with her superior Ingrid Tearney (Sophie Okonedo, The Wheel of Time); the squabbling between MI5's top two women might be more refined than among the Slow Horses, but there's still no one faultless here. As it flits between the service's upper echelons and its lowest ranks, this season also continues to hone its piercing mistrust of everything, especially bureaucratic power. John le Carré (Tinker Tailor Soldier Spy, The Night Manager, A Most Wanted Man, Our Kind of Traitor) meets Armando Iannucci (The Thick of It, In the Loop, Veep), then, and it's as glorious as that sounds. Tense, taut, riveting, rollicking, witty: throw in impeccably penned, staged, shot and acted, and that's the Slow Horses package.

Giving both Scott Thomas and Okonedo more screen time gifts the series some new standout scenes, too, although there's not a moment wasted or a sequence that proves superfluous in this tight and gripping show. Of course, no one will ever best Oldman for Slow Horses' top performance — his blend of slovenly but savagely smart as Lamb is an art in everything from his can't-give-a-fuck gaze to his slicing line readings. And if Lowden pairs this stint of cloak-and-dagger antics with gadgets and martinis as 007, as keeps being rumoured, it'd be well-deserved based on his layered portrayal as Cartwright. It'd be right on theme as well, just as Oldman's jump from Tinker Tailor Soldier Spy to Slow Horses was; being at the summit or the foot of the spy game, and life, can just be a matter of circumstance.

Check out the trailer for Slow Horses season three below:

Slow Horses streams via Apple TV+.