‘Slow Horses’ Is Taking Off: 6 Theories Why Spy Series Finally Broke Through in Season 4

Long regarded as the pinnacle of Apple's Dad TV+ lineup, the Emmy-winning espionage drama is now more popular than ever, thanks to its clever construction and... a bit of luck.

[Editor’s Note: The following article contains light spoilers for “Slow Horses” Season 4.]

A funny thing happened the last time I was asked to recommend a TV show: The person asking had already seen it. Typically, when a stranger finds out I’m a TV critic and inquires what they should be watching, whatever my screen-addled brain can think of is either too new or too random to register. (“What kind of professional television watcher can only come up with one show worth watching, and why is his second choice always a depressing, decade-old HBO drama?”) This time, though, I had a worthy pick. Habitually high-quality and relatively obscure, “Slow Horses” was bound to become this dad-aged partygoer’s new favorite series. But when I suggested the Apple TV+ spy thriller (you always have to include where to watch it), he said, “Oh, I love that show!”

Now, I’m not one to extrapolate success in the streaming age from a single conversation, but there’s more than anecdotal evidence suggesting “Slow Horses” is finally gaining steam. It’s hovered near or at the top of Apple’s original series rankings since its Season 4 premiere. (At the time of writing, it’s No. 2, wedged between a new Bill Lawrence series, “Bad Monkey,” and an old Bill Lawrence series, “Ted Lasso.”) Gary Oldman has been making the rounds, using his Oscar clout to generate extra coverage. The Emmys did their part, not only handing Season 3 nine nominations (the series’ first ever nods) but also a win for Best Writing in a Drama Series. Perhaps most convincing, though, is unbiased data (aka data not controlled by Apple): Per Google Trends, the Interest Over Time in “Slow Horses” nearly doubled between Seasons 2 and 3, before reaching an all-time high in Season 4 (specifically, between September 15-21).

Given Apple’s piddling ratings overall — the tech giant’s originals don’t even rank among the Top 10 streaming services, falling well behind Paramount+ and Pluto TV — it’s no surprise “Slow Horses” still ranks behind Netflix hits and HBO’s I.P. plays. But interest is still spiking, its audience is still growing, and that makes me wonder… why now? What happened to elevate a show that’s always gotten glowing reviews, always had this starry cast, and always been available on the same exclusive service? So as we savor the success — and the excellent Season 4 finale — let’s consider how “Slow Horses” got here. Who knows? Maybe another attention-starved Apple series (or two) can follow in its hoof-steps.

1. The show is very good.

Let’s get the obvious out of the way: “Slow Horses” is an excellent show. Whether you’re watching for pure entertainment or obsessing over every frame, there are rewards aplenty, starting with the cast. Hearing Gary Oldman fart through four seasons of TV has only grown fans’ fondness for him. Jack Lowden, by embodying the fastest slow horse in the race (and the sweetest), ensured no one could question why he gets to marry the mesmeric Saoirse Ronan. And Kristin Scott Thomas may be Second Desk, but she has proven, time and again as Diana Taverner, she is second to no one.

Toss in a sturdy, rotating supporting cast, carefully considered visual language, and extremely high production values — from the meticulous mess of Slough House to the well-utilized location shoots (the Season 4 finale is oh so pretty) — and “Slow Horses” is exactly the type of show that allows audiences to enjoy it on their own terms. And the key word there is “enjoy.” Plenty of TV’s modern greats are largely neglected or ignored because they’re not the easiest shows to sit through.

“Slow Horses” is a pleasure (in part because we can’t smell the odors the characters regularly complain about). It isn’t light entertainment (too many people die, after all), but it is entertaining, and that has to help when it comes to spreading positive word-of-mouth. Finding a high-quality series that’s also consistently entertaining isn’t so easy these days, but we’ll come back to that.

2. The show’s title is very bad (or at least bad enough to put off viewers… until now).

“OK,” you say, “if ‘Slow Horses’ is such a great show, why is it only breaking out in Season 4? Is it one of those shows that takes six hours for it to get good?”

To answer the second question first: No, “Slow Horses” was good from the jump. But it suffered from a few intrinsic, common sense hold-ups. First and foremost, look at the title. Absent any context, it sounds like a miserable time. Slow horses? What are we signing up for here? Giant animals plodding around, snacking on grass? Instinctively, it sounds like the kind of streaming show audiences are fed far too often, where a threadbare plot gets dragged out over hourlong episodes that are actually closer to 70 minutes each.

Visual context only compounds that idea. Just look at any photo of “Slow Horses” and tell me it looks thrilling. Spirited? Funny? No way. You have to watch the show to appreciate its title, its style, and its base appeal. Once you do, you’re not going to forget it, but we only have so much time on this Earth, and audiences are looking for any reason not to waste those precious hours on bad TV.

So “Slow Horses” needed a little extra time to catch on. Each new season was the best case it could make, and each new season accrued a few more curious fans. Better late than never, eh?

3. The show knows it’s catnip to dads — and it’s been leaning in.

Long regarded as the pinnacle of Apple’s Dad TV+ lineup, “Slow Horses” has been catering to its core fanbase more and more each season. Take the ostensible lead, River Cartwright (Jack Lowden). He’s cute. He’s capable. He’s just barely grown up. If any of the banished intelligence agents are going to make their way back into the Park’s good graces, it’s River. But rather than play into his obvious strengths, “Slow Horses” takes every opportunity to kick the living shit out of the handsome young lad.

Not only does this subvert expectations — River doesn’t even get a romantic subplot, and the few women he’s flirted with either die or try to kill him — but seeing the bullheaded striver inch closer to paternal approval only to get bloodied up, mission after mission, while the old guard sits back and pulls the strings is innately appealing to dads. Think about it. Does your dad identify with the hotshot rookie, River, or the senior spy, Jackson Lamb (Oldman)? Does he root for that blonde kid he’s never heard of, or the guy from “Tinker Tailor Soldier Spy” (a dad classic), “State of Grace” (another dad classic), and “The Professional” (a dad classic even though Oldman plays the villain)? Does he have an alarming sparkle in his eye whenever that ornery little whippersnapper runs face first into a flurry of fists, or falls down a flight of stairs, or gets blown up with a grenade?

You bet he does, and “Slow Horses” has provided plenty of scenes emphasizing the older, wiser Jackson is still a better spy than his aspiring steed. But Season 4 twists that idea by taking it a step further — appearing, even, to take a step too far. The first episode, “Identity Theft,” sees David “O.B.” Cartwright (Jonathan Pryce) on the decline. Affectionately (and sometimes not so affectionately) nicknamed “The Old Bastard” (or just O.B.), the retired top agent may be losing his marbles. River tells Louisa (Rosalind Eleazar) that he’s worried his grandpa’s Alzheimer’s is getting worse, along with his paranoia, and he may not be able to take care of himself anymore. “The last time I saw him,” River says, “he genuinely didn’t know who I was.”

So, a few minutes later, when an unseen man who sounds a lot like River visits O.B. and the old bastard shoots this man in the face, it’s all too easy to believe that River was too late voicing his concerns. That his grandfather lost his faculties, and his delusions resulted in the death of his grandson. For an extended portion of the episode, we’re meant to believe River is dead, and his grandfather killed him. Even though this doesn’t turn out to be true, the brief window where it might be true forces viewers to reconsider the show’s established relationship between fathers and sons through a familiar lens: mortality. At what point does age become more of a detriment than an asset? When will all those dads watching know to cede certain decisions to their kids? Can they set aside their pride, their position of authority within the family, in order to protect themselves and their loved ones?

Answering these questions isn’t easy, and by posing them, “Slow Horses” risks dividing its audience. (The finale’s resolution is particularly emotional.) But by waiting until Season 4 (roughly in line with Mick Herron’s books), the series has earned the opportunity. There’s always been a bit of push and pull between generations, with River proving himself and Lamb making a mistake or two. But now, after years of catering to dads, “Slow Horses” can challenge them, too.

4. The show isn’t just Dad TV. It’s also for the people.

OK, enough about dads. “Slow Horses” is so much more than that oft-tagged label. Moms must feel seen whenever Standish (Saskia Reeves) puts Lamb in his place. Kids certainly aren’t complaining about watching Jack Lowden / Mr. Saoirse Ronan every week. But my favorite demo from which to see “Slow Horses” through is the working class.

Slough House consists of a bunch of blue collar workers who’ve been thrown under the bus by the white collar executives above them. Sure, sometimes their demotions are warranted, but that shouldn’t make them expendable pieces of meat, as they’re so often treated. These agents have to do what they’re told, or else they’ll be out on the street. This is their last chance, the bottom of the ladder, and below is a fate none of them are prepared to face.

Does that, uh, sound familiar to anyone? Working day and night for people whose status and wealth creates a clear, unbreakable barrier between you and them? Clinging to a job that could very well kill you, but without it, you’d be lost (or worse)? Doing your best because you know it’s the right thing to do, only to be ignored, chastised, or discredited?

Our beloved slow horses know the people at the Park don’t care about them. They know they’re being used, manipulated, or forgotten, but that knowledge does little to protect them, let alone offer any relief from the boots on their necks. Instead, it just makes them very, very grumpy.

But for those of us watching, their surliness is identifiable, even invigorating. We are their witnesses when no one else can be, and they are our surrogates — sprinting at top speed, fighting with all their might, and generally taking out their frustrations in ways that we, the deskbound office drones of the world, cannot. That Season 4 ties River’s frustrations at work so directly to frustrations at home only makes everything all the more personal. It’s not just his life he’s fighting to save. It’s his grandfather’s. It’s not just his own sense of purpose, his own financial needs, his own career that’s keeping him at Slough House. It’s for his family, too.

Everyone can relate to that — well, unless you’re part of the Park. Then, at least you’ve got Kristin Scott Thomas for style inspiration and enough money not to care.

5. The show finally got some Emmys love.

More of an indication that “Slow Horses” is gaining popularity than an additional avenue to more viewers itself, the Emmys did embrace Will Smith’s series in its third season — in a big way. Landing nine nominations (after the previous two seasons were completely shut out), “Slow Horses” earned recognition for Gary Oldman, Jack Lowden, and Best Drama Series, among others. Some of those nominations had been prediction (Oldman was considered a favorite), but some weren’t and the sum total was impressive. Then it won. Smith took the stage during the Primetime Emmy telecast to accept his trophy for Best Writing in a Drama Series, and suddenly, “Slow Horses” was among TV’s elite. Right there rubbing elbows with “Shogun,” “The Bear,” and “Hacks.”

While I’m sure the additional exposure didn’t hurt viewership, this year’s Emmys did not attract a large audience, which makes it harder to argue the awards helped turn Season 4 into a Show People Talk About. One could also argue the only reason “Slow Horses” saw a surge in TV Academy attention was because this year’s drama categories were as empty as Jackson Lamb’s refrigerator. Still, the Emmys did air while Season 4 was rolling out, and a bit of luck leading to added exposure still counts as added exposure, so who knows? Maybe a few hundred red carpet watchers crossed over to check out Lowden’s less glamorous fits.

6. The show is different from other spy stories, but it’s also different from the vast majority of streaming TV.

Much has been made of how “Slow Horses” distinguishes itself from similar spy-genre fare. These agents aren’t James Bond or even Jason Bourne. They’re clumsy and often incapable. They don’t have fancy gadgets or even basic resources. (In the finale, Marcus, played by Kadiff Kirwan, has to leave Slough House to buy his own gun.) Their boss can’t stop farting. (M would never.)

All of that certainly helps “Slow Horses” stand out from today’s “Jack Ryans,” “Night Agents,” and “Old Men.” But perhaps more important to its success is how it stands out from the rest of today’s TV in general, not just within one genre. Episodes are short by streaming standards, with Season 4 averaging 45 minutes per entry. Seasons are also short — just six episodes each — and every season is relatively self-contained. The beginnings set up a fresh mystery, and there’s always real, substantive closure by the end. All of this runs in contrast to the plague Netflix unleashed on entertainment: bloat. Audiences have to be sick of waiting around for anything exciting to happen, which makes “Slow Horses” feel like a brisk parade of taut action and plentiful payoffs.

Perhaps even more refreshing is the expedited wait between seasons. Because the production team shoots seasons back to back, the longest audiences have waited for new episodes is a mere 11 months. Compare that to Apple’s other acclaimed, Emmy-winning drama series, “Severance,” which is set to return with Season 2 in January 2025… nearly three years after it first premiered. These days, those kind of lengthy delays have become closer to the norm than the exception, so if fans are aggravated by the holdup and find their connections to characters frayed, then an accelerated release should do the opposite: delighting viewers through regularity and intensifying their relationships with everyone in Slough House.

The pace should continue for the foreseeable future. Apple renewed “Slow Horses” in January for Season 5, which will be based on Herron’s fifth book in his “Slough House” series, “London Rules.” Not counting novellas, that leaves three more books to adapt, the completion of which seems all the more likely with the one-two punch of Emmys attention and added viewership. “Slow Horses” may just be hitting its stride, but there’s still plenty of track ahead.

“Slow Horses” is available on Apple TV+. The Season 4 finale will be released October 9. Season 5 has already been renewed.