[Editor’s Note: The following contains spoilers for the Slow Horses Season 4 finale]

The Big Picture

Collider’s Steve Weintraub speaks with
Slow Horses
writer and showrunner Will Smith about the Season 4 finale and beyond.
The spy thriller follows MI5 rejects led by Oldman’s ornery Jackson Lamb, investigating dangerous plots.
Smith teases Season 5, discusses casting Hugo Weaving, working with Mick Herron, and potential future content.

Master satirist Armando Iannucci clearly found something special in writer Will Smith, hiring him time and time again for his esteemed productions. After winning awards for writing classic shows like Veep and The Thick of It, Smith was finally given reign over his own series, Slow Horses. With an amazing cast rounded out by Academy Award-winner Gary Oldman and Academy Award nominees Kristen Scott Thomas and Jonathan Pryce, Slow Horses has garnered great critical acclaim and audience enthusiasm.

Spy thriller Slow Horses follows a cadre of MI5 rejects, spies who have been sent to indefinite desk duty due to their past failures. There, these “slow horses” are pushed to their limits by Oldman’s extraordinarily ornery Jackson Lamb (Oldman), tasked to work on the organization’s most boring assignments. Yet, through it all, Lamb and his team find themselves investigating Britain’s most dangerous schemes.

With the Slow Horses Season 4 finale now streaming on AppleTV+, Collider’s own Steve Weintraub spoke with =Smith about how Slough House series author Mick Herron feels about his series’ Emmy-winning adaptation, why Smith didn’t bother telling the cast or crew that he’s actually Hugo Weaving’s cousin, how they decide what Oldman will eat each season, and if they’d ever make a Slow Horses Christmas special. They also talked about why the season started with the rotisserie chicken being cooked and ended with River and Jackson having a drink at the bar. And for fans of the series, Smith also gave us an update on how Slow Horses Season 5 is shaping up.

Check out what he had to say below.

Gary Oldman Eats Through Blocking, Dress Rehearsal, and Every Single Take
Image via Apple TV+

COLLIDER: I’m a little bit mad at you because each season it ends, and I’m not really down with that. It needs to be a show that I can turn on Apple TV+ whenever I want and there’s a new episode.

WILL SMITH: Did you get the teaser for the next one, or was that not on the preview copy?

It was not on the preview copy. I went to the very end of the credits, hoping it would be there.

SMITH: It’s gonna be there next week. We’ve nearly done Season 5. We’ve got a couple of days to finish off on it, but we’re already into the edit, so it’s coming. Don’t worry, it’s coming. Not as quick as you want, but it’s coming.

I have questions about that, but let’s start a little earlier. How do you decide what you want Gary Oldman to eat and drink each season?

SMITH: We try and give him some new foodstuffs. I’m trying to remember what he’s got in this one.

He’s always drinking.

SMITH: He’s always drinking. This was the quest for Jaffa Cakes. [Laughs] He’s hungover and just not in the best place. I just love the idea of him turning up at Catherine’s with Jaffa Cakes, and that’s his breakfast. But we have to watch it because Gary commits to those eating scenes, and he will eat them in the blocking and the rehearsal and the camera rehearsal, and then we’ll do eight or nine takes, and it’s like, “Oh my god, give me another ice cream.” But no, he’s amazing at that.

Did you have any consideration, knowing that, with Season 5, finding something that he likes that’s healthy for the hell of it?

SMITH: No, we’re gonna start to do that because in Season 5, there’s a scene where he has to eat quite a lot of cake, and he ate too much cake. He had a bit of a sugar rush, and so we got it right. Sugar-free next time, or maybe Lamb has crudités, but nobody dares ask why.

Slough House Creator Mick Herron’s Is Involved Throughout
Image via Apple TV+

Do you know what Mick [Herron]’s reaction has been to the success of the series, and have you talked to him about whether he’s writing for the future?

SMITH: Mick absolutely loves it. He’s delighted with what we’ve done for it. Obviously, he’s thrilled with the success. He’s always involved. He’ll come into the beginning, the middle, and the end of the writers’ room, and I’ll tell him, if we’re changing his stuff, why we’re changing it. I always bring him along on that, and he’s always really supportive of anything we do change. He usually comes on set during the filming, as well, and then we’ll show him the whole thing in one day once it’s done. I always get a very effusive email of, “What’s the latest one? It’s fantastic.” So, he’s really thrilled.

He’s working on book nine, which I can’t wait to read. So, yeah, he’s just so happy. Especially because, as you and your readers probably know, it was not obscurity, but he’d been writing for years and was still not successful enough to give up his day job, and Slow Horses was dropped by the UK publishers and then picked up by the American one. It’s been a long journey for him, and to be as successful and on top as he is now after all that, he really is pinching himself.

I’m sure he’s also enjoying the Apple paycheck. Whatever’s coming in, I am sure he is enjoying it.

Will Smith on ‘Slow Horses’ Critical Success
“I think that part of the reason the show is a success is because there is a sort of purity to it.”

Where do you keep the Emmy that you won for “Negotiating with Tigers?”

SMITH: It’s on the sideboard. It’ll go upstairs somewhere at some point. It’s a lovely, fantastic thing to have and and it was really nice. I’ve had some very nice messages from people I really, really admire who I don’t know, but who make shows that I absolutely love saying congratulations. That means the world to me.

So the show is a critical darling, and fans just love it. It’s one of those rare shows that you look around online and you don’t see people complaining about it. It’s a uniform positive thing. So, my question for you is when you’re working on Season 4 and you’re working on Season 5, do you feel more pressure now working on it because everyone loves it, or do you sort of feel like, “They like what I’m doing. It’s gonna be okay?”

SMITH: It’s a pressure that I know is there, but I try and put it out of my mind. I read as little as I can. I don’t want that to pollute the process if that’s the right thing. It’s not that I don’t wanna know what people are saying, but while we’re in it and we’re doing it, I just wanna keep the channel between Mick’s books and me and the cast. I don’t want things getting in the way of that. I think that part of the reason the show is a success is because there is a sort of purity to it. It’s a slight highwire. I’m on a highwire here, and I don’t wanna look down, and I don’t wanna jump up and down. I just wanna keep carrying these bars along the tightrope, and I hope we don’t mess it up.

So, yes. There’s a kind of responsibility and a pressure, but I feel the responsibility and the pressure to the cast first of all. I don’t want to give them stuff they’ve done before or that isn’t interesting and fun. I feel as long as the cast are happy, and as long as Apple and the producers and the execs are happy with the material, then you trust that all the audience will be. It will follow from that. So, I am thinking of the audience and the reviewers and all of that, but “if I do this bit, that’ll sort that bit out” is kind of how I think of it.

Related River Is in Trouble (Again) in New ‘Slow Horses’ Season 4 Sneak Peek [Exclusive] The penultimate episode of Season 4 airs this Wednesday.

Have you been approached by any real spies or intelligence people at any event who have been like, “It’s very good, but you need to add this?”

SMITH: Not yet. No direct contact in that way, but I do know that the show is as popular with people who work in MI5 as it is with the public. I can say that, but I can’t really elaborate further. But no, I haven’t had any kind of intel in terms of, “Yeah, you could do this story,” or, “That’s funny,” or, “Oh my god, I work with Claude Whelan,” which would be terrifying. I don’t wanna hear that, you know? So, no, not yet. But I’d be fascinated to hear the inside track on that.

Six Episodes Keep ‘Slow Horses’ Audiences Wanting More
Image via Apple TV+

Each season is six episodes. Do you ever see a future season being more or less than that, or is that the magic number?

SMITH: It’s the magic number for now. Both Graham Yost and Doug Urbanski, our execs, have always been convinced that that’s the right number. I totally agree. I think, because the books often happen over a two or three-day period, they’re quite intense in terms of the plot. You feel if you stretch it beyond that — I mean, you can invent — I worry it would feel like padding, and it would take you away from what is great about the books. So, six, I think, is the magic number.

I do think, though, there’s a great book he wrote, the last book that came out, which is in the Slough House universe, and Slow Horses do come into it, which is called The Secret Hours . That could be a movie or a more limited number just because of the nature of that story. But in terms of the main books, I think six is the one. I know that people are like, “Oh my god, I want more,” but I’d rather that people went, “Oh my god, I want more,” rather than, “They dipped a bit in the middle. It was okay.” It’s like when we kill characters — you want people to be upset and, “I can’t believe you did that,” because otherwise if they don’t care that you’ve done it, you left it too long. With things like that, it’s the same with the episode lengths — you want people chasing it.

I also think that if you had a book and you were breaking it down and you’re like, “This really needs to be seven or eight episodes,” I’m sure everyone involved would be like, “Yeah, let’s go do that.”

SMITH: Absolutely. Definitely. I know there’d be the will for that, and I know Apple will be completely supportive of that, but so far, with the books we’ve adapted, it feels like six feels right for the story, so that’s what we wanna do.

The Evolution of Jackon Lamb and River Cartwright’s Relationship
“I love the poignancy and the kind of sadness in many ways.”
Image via Apple TV+.

Season 4 started with a rotisserie chicken being cooked, and it ended with River and Jackson having a drink at the bar. How did you decide to start with the rotisserie chicken and end with them having the drink?

SMITH: Season 1 starts with River, but you don’t know him as a character yet. And then Seasons 2 and 3 start with new characters, who then die — sorry, spoiler, if you haven’t watched them yet. And we thought to break that it’d be fun to start with the Slow Horses and the idea of how turning up to a Christmas party that isn’t happening just felt too funny to resist, and also that it’s just a kind of fast food restaurant. Then at the end, one of the things I love about this season, and I love how each season is different, in this season, River has one scene with Louisa and no scenes inside house. One scene with Louisa, and then he’s not with any of the SlowHorses throughout the whole series until that final scene. The only moment you get with Jack [Lowden] and Gary, with River and Lamb, is right at the end.

Actually, we did shoot a version where they don’t even say a word, where you get those two together and then you don’t even give anything, but it felt like after all that, you wanna give something. For me, it’s a very bittersweet moment because, across the series, River has lost, to a certain extent, his grandfather, whose mind is fading, and he’s also had the image of his grandfather shattered. He’s found his father but realises his father’s a monster, and he’s left with Lamb as his only father figure. Thematically, I love the poignancy and the kind of sadness in many ways of that ending. I just love those two actors, so it was quite great. You just know they’ll play that beautifully.

By the way, I could see them sitting together and not saying a word and it totally making sense, but the way it ends is great. Is it actually Jackson feeling bad for River filling out the report? I mean, that is just shocking.

SMITH: I think Lamb would never say it. I’m slightly speaking for Gary here, but we did discuss it, actually. Lamb kind of knows what he’s gone through, and he’s never gonna put his arm around him and say, “Are you alright, kid?” So the best he’ll get is, “You can sit next to me and drink, but just don’t talk to me.” That’s the most support you can get. But, like all the Slow Horses, River’s got nowhere else to go. That’s that’s the thing. They’re all alone with each other, and this is the only family and friendship they have, and it doesn’t even work as a friendship or a family. So, it just felt like that’s as much support and affection as you’re gonna get from Lamb is filling the form for him, which I think is the primary motivation of being there. I don’t think he’d have called him there if he didn’t want him to do the form, to let him have a drink with him because he was having a bad day. But now he’s here, knowing what he’s been through, so, “Oh, alright, may as well have a drink.”

Hugo Weaving Has an Interesting Relation to ‘Slow Horses’
Image via Apple TV+

Hugo Weaving is obviously a very talented actor. Talk a little bit about getting him on the show. Is there a future for Hugo’s character in Season 5 or future seasons?

SMITH: All I can say is that Hugo’s character reappears in the books. That’s the only tantalizing glimpse I can give you of that. In terms of getting him, it was slightly odd in that he’s actually my mum’s cousin. My grandfather is his uncle. It’s a strange thing. So, I’ve met him over the years. I’ve been out to Australia and stayed with his family, and he’s been at family events. He was actually at my wedding, and he was filming at the time.

I always saw him as Frank. Really, there were two people who I wanted — Joanna Scanlan for Moira and I wanted Hugo for Frank. I just knew that they were those characters. Because Hugo is brilliant, and I’d always wanted to work with him, I thought there’s enough of a similarity with Jack that you don’t immediately think that the family relationship is there, but when it’s revealed, it makes sense. So, he was the one we wanted, but I didn’t tell anyone that we were related because I just thought it might be odd and people were thinking I was doing it because we’re related and that I was back-channeling with him in some way. So, I didn’t talk to him about it, he didn’t talk to me about it, and then when it was all done, the people on the show were saying to me, “I’ve just heard from his agent, apparently he’s your cousin. Did you know that?” I was like, “Yes, I did.” But then that left the slightly strange question of, “Why didn’t you tell us?” I was like, “Well, it just felt odd.” [Laughs]

But it was absolutely fantastic. It was a real dream come true working with him not just because I love him as Cousin Hugo, but because he’s a phenomenal actor who’s had so many iconic roles in incredible films that we all love, and he was just tremendous as Frank. Just the kind of the menace and the power, he just roared through it and everybody loved him.

Yeah, he’ll land on his feet.

‘Slow Horses’ Season 5 Is Almost Done Filming
Image via Apple TV+

Let’s talk about Season 5. How many days left of filming do you have?

SMITH: I think three or four.

You’re really close to the end.

SMITH: Yeah. Really very close to the end.

So, the show has been on basically every year. The one thing I like is that this show doesn’t do CGI, so the turnaround is not brutal in terms of getting it on the air. It’s now October. Do you think it could be out next summer, or do you think it’s a year away?

SMITH: I genuinely don’t know the answer as to when it’s gonna be out, but I can’t imagine that Apple would want to leave it longer than a year since Season 4. So, the latest it would be out, I would say, would be the same slot next year. They’ll want it as soon as we can get it out, I would imagine.

In an ideal world, eight months, nine months is great because you build it up. You want people to be excited when it’s coming back.

Related Gary Oldman Reveals Which Important ‘Slow Horses’ Season 4 Scene Was “Infuriating” To Shoot He also discusses the importance of that torturous choice for Lamb.

The fact is, this show is not getting canceled. There’s a 0% chance with the awards and with everyone raving about it, so where are you in the writing process of Joe Country ?

SMITH: I really can’t say anything about Season 6. All I can say is Season 5 is coming and everyone’s very, very happy with it. So hopefully, the trajectory will continue and the audience will continue to grow and the audience will continue to like what we’re doing.

I like how you’ve been told not to talk about it. It is obvious that it’s coming back for Season 6. When it’s up for major awards and it’s always in the top five on Apple, it’s a question of when does Gary not want to do it? That’s really what it comes down to.

SMITH: Gary seems happy. He keeps saying to just go forever. It’s Gary and Mick. If they’re still there, it’ll keep happening.

What do you think about the novellas?

SMITH: They’re great!

The thing is, there is a way of doing a novella that’s not six episodes but in between — not a spin-off but like a spin-off.

SMITH: Like a special one-off episode where you meet John Bachelor. That’s a great one.

Will There Be A ‘Slow Horses’ Christmas Special?
“What do you think Lamb’s Christmas is like?”
Image via Apple TV+

Doctor Who does the Christmas specials, so I’m wondering if it’s like the Slow Horses Christmas special is whatever that novella was.

SMITH: Gary and Gisele [Schmidt], his wife, had a fantastic idea that I loved, which was to do a Slow Horses advent calendar where we did 25 little films, and you kind of went in each day like an advent calendar, but you could dot around the timeline. So, you could maybe do one where Min was still alive, and you could just go in and have these little vignettes. I’ve also spoken to Gary about, “What do you think Lamb’s Christmas is like, his actual Christmas Day? Where’s he going?” We think he probably goes to the pub on his own. But that would be a great thing to do.

The novellas, because they often lead into the books, would be great. Secret Hours would be great. There’s a wealth of ancillary material to explore and to drop in if we are taking our time delivering the next season. There’s a stop gap.

You brought back Saul Metzstein for the director of Season 5. Was it one of these things where he wanted to come back or where you wanted him to come back? How did you decide?

SMITH: It was both. We love what he did in Season 3 and thought he’d be a great fit for the tone of Season 5, and it all lined up, especially because we’ve got a quick turnaround in terms of the production cycle. It’s just, “Oh, great, he knows the ropes. The cast knows him, the crew knows him.” He’s great. I know him. We’ve got a shorthand. I love working with Saul. I love working with all the directors. They’ve all been absolutely phenomenal, all different. I love that each series feels slightly different, and so we’ve just been blessed with the people we’ve had on this.

Slow Horses Season 4 is available to stream on Apple TV+.

Follows a team of British intelligence agents who serve as a dumping ground department of MI5 due to their career-ending mistakes.

Watch on Apple