Slow Horses Showrunner on Not Being Afraid to Kill Characters

British writer Will Smith, a veteran of sitcoms like The Thick of It (for which he won two Emmys), Veep and Avenue 5, is not the first person you might think of to adapt a series of spy novels to television. But when Smith was offered the chance to bring Mick Heron's Slow Horses book series to television, he jumped at the chance.

Like its literary source material, Slow Horses the show centers on the agents of Slough House — the deadest of dead-end divisions within MI-5, Britain's domestic spy service. With Oscar winner and Emmy nominee Gary Oldman (Darkest Hour) on board as Slough House's jaded station chief, Jackson Lamb — and a winning supporting cast that includes Kristin Scott Thomas, Sophie Okenedo, Jack Lowden and Jonathan Pryce — the series alternates seamlessly between brutal action, life-and-death tension and laugh-out-loud humor.

With the recent conclusion of the pivotal third season — and with the fourth season still awaiting a premiere date — Smith took a break from the Season Five writers' room to talk to the Television Academy about bringing Apple TV+'s sleeper hit to streaming.

Television Academy: How did you get involved in the first place?

Will Smith: I think [EP] Gail Multrux had found the books in America, thought they'd be great TV, but knew that it needed a British production company. She teamed with See-Saw Films and Jamie Laurenson, who had read a spec script of mine that he really liked. We were talking about that [spec], and because the books are really funny as well, and I'm a huge John le Carré fan, the short pitch became Tinker Tailor Solder Spy meets The Thick of It. Jamie thought I'd be a good person to adapt them; I'd never met anyone like Jackson Lamb, and I just thought, "Oh, this is sort of everything that I like, and everything I hope I'm good at."

You mentioned the mix of drama and comedy — how challenging is it to balance those two tones consistently, especially in the spy genre?

There was a worry about the tone [in terms of] how to navigate it. "Can you be funny whilst you're doing action?" I was personally never worried, because I thought, "Well, Mick does it in the books, and I don't question it." Take Lamb, for example — humor is part of his character. He uses it to put people on the back foot to dominate, manipulate, whatever. It's a tool. It might seem gratuitous, but it isn't. It's something I learned from working with [Veep creator and showrunner] Armando Iannucci. It can never feel like they're doing a joke. It has to feel like the line is dramatically earned, that there's a reason for them to be saying that in that moment. If you get that right, you're feeling for the characters. Laughing with them. When they're in danger, you're worried for them. When they die, as they do a lot in Mick's books, you're devastated by the loss.

Interesting you say that, because you tend to kill off a lot of characters. Is that all from the books?

I don't think we ever want to deviate from what Mick does in that, partly out of respect, and partly because I just think he judges it so perfectly. Also, my feeling about characters dying is: If you do it and the audience isn't upset, you've left it too long. It helps create a real throughline for the show, from one season to the next, too. I think the actors really enjoy tracking through what's happened to them and showing the scars as each series goes on.

Speaking of the actors, the talent across the board, down to people with one line, is impressive.

Well, I think having Gary brings a lot of those people in. I'll be totally honest, there have been two occasions where we've really swung for it, and I'd been the idiot guy saying, "Yeah, that'll never happen, this is a waste of time." One was, let's try and get Mick Jagger to do the [opening credits] song. The other was, Gary's the Oscar-winning movie star, why would he do TV? Then he read it and loved it. To get Gary was like a bolt from the blue I never thought would happen. That just elevates everything. Also, we have the greatest casting director in the industry in Nina Gold.

Since you mentioned Mick Jagger, how did he get involved with doing the show's opening theme song?

Turns out, Mick Jagger loves the books.

That's a very lucky happenstance.

We're just so lucky. I mean, Gary said as we were doing the first [season], because we could all feel that there was something special. It's the right material, with the right writer, with the right producer, with the right director, with the right streamer, with the right lead actor at the right time.

So even as you were making the first season, you and Gary knew that you really had something?

I don't want to sound crazy and egotistical, but I would watch a take, and just think, "You could put that on the telly." No music, no effects, no mix, nothing. It's weird to say that I am a fan, because obviously I made it, but I was mocked for this in the edit once by the other execs. We were watching a thing and I started laughing. They were like, "Are you laughing at your own work there?" And I was like, "No, I'm laughing at Jackson Lamb." And you think, "Well, if it's working on the monitors, we've done all the magic."

Each season, you've had a single director helm all six episodes. For Season Three, it was Saul Metzstein. What was the decision behind that?

I'm gonna chalk that up to [EP] Doug Urbanski, who was just very adamant that it's one director per book, per season, and it's like a six-hour film. You get one vision. I think that's just worked absolutely brilliantly. Directors love that challenge, and it's great for the actors as well, because they've just got one voice.

So the third season has aired, the fourth is in the can and awaiting an official 2024 premiere date, you're writing Season Five, and Mick is writing Book Nine. How long do you think the show can go?

Gary openly says, "I'm happy to keep doing this for the rest of my career." So, as long as Gary wants to do it, and as long as Apple want us to do it, we'll do it as long as there's an audience for it. For me, I just feel as long as we can make the next series better than the last, you always want to be pushing it and elevating it. That's obviously a challenge the longer you go on.

This interview has been edited for length and clarity.

Slow Horses is now streaming on Apple TV+.