Kadiff Kirwan on The Importance of Comedy, On-Set Collaboration, and Brilliant Writing.

35-year-old Monserrat-born, Lancashire-raised Kadiff Kirwan moved to London at the age of 18 to pursue a career in acting. Since then, he’s been busy. From ultra-beloved British TV shows like Michaela Coel’s Chewing Gum and Phoebe Waller-Bridge’s Fleabag, to productions in the National Theatre and the Old Vic, to feature films like Mary Queen of Scots—Kadiff’s varied roles speak to his range and momentum. 

Photographer, David Reiss

Grooming, Lauraine Bailey

Styling, Way Perry

With his warmth and enthusiasm no less palpable on a video call, Kadiff talks to New Wave about the ‘explosive’ Season 4 of Slow Horses, in which he portrays Marcus Longridge. This new season is Kadiff’s third on the show and premiered on the 4th of September on Apple TV. 

Kadiff Wears: Diesel (Full Look), Adidas

NW: Hi, Kadiff, how are you doing?

KK: I’m good! Sort of rested… I'm doing a theatre production at the moment at the National Theatre  called the Hot Wing King, and we do eight shows a week. So I had two shows on Saturday—Sunday is my only day off!

NW: Well, thank you so much for taking the time to talk about Slow Horses. Season four is about to come out, that’s very exciting. It’s your third season with the show—you’ve been a part of it for over two years now. How did you feel about it when you first picked up the script? 

KK: Well, when I read the script, the tone was unlike any tone I’d come across before. It’s about a motley crew of spies who for one reason or another have been relegated to a unit that no one wants to be in. It’s sort of spy drama meets British workplace comedy, with this resentment of the mundanity of the day-to-day jobs. And I thought, oh, this sounds interesting.

NW: What was it like joining a cast after a whole season? 

KK: Myself and the actress who plays Shirley Dander, Aimee-Ffion Edwards, were two new cast members that joined for Season 2. And, you know, you get nervous because you're joining something that's already sort of established. The cast have already met each other, and they've spent six months together. So it was sort of like, you're starting school halfway through the term. But actually, it wasn’t like that at all. The cast welcomed us and working with Gary [Oldman] was just 20 out of 10, one of the funniest, kindest, most collaborative people I've ever had the honor of working with. Slow Horses has been one of the highlights of my career, but also my life. 

NW: So, what can we expect from the new season?

KK: I think it’s the best season yet. I think we’ve pushed ourselves and challenged ourselves in ways that we couldn't have imagined. The characters are all being challenged—there's ghosts from the past that have come to haunt the Horses, which affect every person in the team in a very different way. And all those night shoots, all the action sequences, all the stunts and explosion rehearsals—I think it’s all been worth it because we've made something that I hope the public will embrace and enjoy and want more of. So yeah, season four, look out! It’s—this is the word I keep using—explosive. 

NW: The Slow Horses are all pretty feisty, assertive and argumentative characters, and they’re also all frustrated with their professional failures. All this causes a lot of tension between them—that’s sort of the fundamental dynamic. How do you navigate such a full, flamboyant cast of characters—how can each actor do their character justice? 

KK: I think with Slow Horses, on paper you go, oh God, all these people together in one scene, how’s that gonna work. Well, it’s the writing. The writing is so specific and so particular but there’s those little breaths where someone just breathes something unique into their role, and you react in the way that your character would, and that just elevates it to another level. We’re quite playful as a company of actors. And our brilliant, brilliant, brilliant showrunner Will Smith—he’s so collaborative. It's just this constant thing of nurturing the story. No one's trying to steal the spotlight because the spotlight's on all of us at the end of the day.

NW: Slow Horses definitely handles its bleakness with humour. What do you think the value of that is, in the show, and in general?

KK: Well—you catch more flies with honey, you know? If you can sweeten the thing, you can process it. It’s a reflection of life—in terrible situations, laughter can be an absolute wash of relief. You become grateful for it. And—it’s harder to make someone laugh than cry. What I love about what I do, I get to bring a tiny bit of joy to someone's life. For me, making people laugh is my ultimate mission, genuinely. Even if it’s just on the bus or on the tube or my colleagues at work. I think humour can be a gift of respite. 

NW: So, is that at the core of why you act?

KK: Yeah—I just want to keep playing. I want to keep entertaining people, making people think, making people laugh and making people cry every now and again. I think the world is a pretty dire place at the best of times for many reasons, but it can also be a place full of joy and hope. I love what I do, and I want to keep doing it.

It's clear that his excitement for Season 4 of Slow Horses is contagious. With the show's signature blend of suspense, dark humor, and unforgettable characters, including Kirwan's dynamic role, fans are in for another thrilling ride. Kadiff's passion for the project, his admiration for the talented cast, and the gripping new twists awaiting us all make this season a must-watch. Don’t miss Season 4 of Slow Horses—it promises to be the most explosive yet.