‘Slow Horses’ Antagonist Hugo Weaving Teases Thrilling Finale: “Great Way to End a Season”

All the pieces are in place for a gripping Slow Horses finale — season four antagonist Hugo Weaving certainly thinks so.

The Brit, best known for his role in The Lord of the Rings trilogy, joined this season’s cast of Apple TV+’s hit spy thriller based on the Slough House series of novels by Mick Herron. Weaving stars as Frank Harkness, a former CIA agent-turned-cult leader aiming to populate the planet with trained killers (who will gladly do their father’s sinister bidding).

But as the season has unfolded, viewers have come to realize Harkness might be none other than River Cartwright’s (Jack Lowden) biological father — after all, the physical similarities between River and “Robert Winters” a.k.a Betrand, who Jonathan Pryce’s David Cartwright shot and killed, are pretty eerie.

Meanwhile, Gary Oldman‘s greasy, drunk yet impossibly wise Jackson Lamb has made it his mission to locate the elder Cartwright, who is suffering from dementia and losing his memory. Although Catherine Standish (Saskia Reeves) has not been too happy with Lamb’s methods, the Slough House leader plodded on and harshly convinced David that his grandson, River, is dead. When David admits he did it all “for her,” referencing his daughter, the former MI5 officer’s involvement with Harkness becomes terrifyingly clear.

Isobel, River’s mother (played by Anna Wilson-Jones) was taken and impregnated by Harkness at Les Arbres. In order to get his daughter back, David explained he traded with Weaving’s character the cold body passports and supplied Les Arbres with weaponry and money.

This is all the while Emma Flyte (Ruth Bradley), the new Head of the Dogs, is attempting to track David down. Kristin Scott Thomas stars as Diana Taverner, Naomi Wirthner as Molly Doran, Rosalind Eleazar as Louisa Guy, Aimee-Ffion Edwards as Shirley Dander and Kadiff Kirwan as Marcus Longridge in the highly anticipated season four finale, “Hello Goodbye” (airing on Oct. 9 on AppleTV+).

Below, Weaving speaks to The Hollywood Reporter about turning to Herron’s books for inspiration, why Frank Harkness helps focus our attention on what Slow Horses is truly about, and what audiences can take away from the season finale while awaiting the already renewed season five: “For a viewer, I think it works. It’s a great way to end the season.”

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I’m interested to know, were you a fan of the show before your involvement?

I had literally just said to myself, “I’ve gotta watch Slow Horses.” I’d heard about it and I thought I must watch season one, because there’s [lots of] things I want to watch, you know? Then the next day, I got an offer to play Frank with six scripts. And I thought, “Well, now I’ll definitely watch it.” So I read the script, and I watched season one pretty much the same day.

It was a fantastic role, and very easy to say yes to. One of the things I did before I signed off on it was that I wanted to also read the books that Frank appears in. I really raced to read anything to do with Frank. I read three books just to get as much information on Frank as I could that wasn’t actually contained in the season on screen at the moment.

Did you find that you were letting that character in the books influence your portrayal on screen?

Yeah, it did. I wanted to see what Mick Herron had to say about Frank, who he was from Mick’s point of view. Because it’s the man who created him, initially. And then, what’s the difference between Frank in the book and Frank in the series? And there were definitely differences in emphasis. I always want to bring as much complexity as I can into any character, as much contrast. Because the more contrastive anyone is, the more real they are. To me, all human beings are complex. So I’m always fascinated about complexities in characterization and in character, and Frank is a gift, in a way, because he’s like a father figure. So he’s meant to be a teacher, a nurturer, right? But he’s also lethal. He’s also a killer. You’d be really incredibly wary of having anything to do with this man. That’s a fabulous dichotomy, I think. He’s a great new addition to the Slow Horses family, and he’s a fascinating man in his own right.

And your portrayal is extremely sinister but has so much depth. Is playing the villain ripe ground for you?

I do talk about the villain, but from an acting perspective, I never think of the character I’m playing as being the villain. I understand that maybe in the in the construct of the film or the TV series, that is the role. But I don’t find that useful. It’s useful to know, but then you can’t do much more with it. Finding the human being, that is what you have to chase down.

Do you find Frank quite different to characters you’ve played before?

Yeah, I do. I think he’s someone who works in the shadows. He’s in intelligence. He’s a secret, and he’s also gone off piste. He’s clandestine, he’s rebellious. He went against his own organization, the CIA. He’s highly evolved in one way and he’s unsentimental. He knows exactly what secret services do and what they sometimes need to do, and how some of the things they get involved in need to be completely deniable, like, “We have nothing to do with the killing of this world leader. We didn’t do it.” He understands that, and I think that’s the world in which he operates. So his experience is really unusual. It’s not something that most people would have. And yet as a human being, when we see him and he’s face to face with someone, he needs to not appear to be that. Unless he wants to be threatening, he needs to be pleasant, polite, charming, obeying. He’s intensely capable but also buried, hidden. Those things don’t reveal themselves very often because they don’t need to, and they shouldn’t. Otherwise, he’s not doing his job properly.

I’m cautious that you can’t reveal too much, but with the finale coming, what can we expect? Is there a confrontation between Frank and River? Is Frank River’s father, as viewers highly suspect?

[I love] this whole idea about Slow Horses being centered on a dysfunctional family. Slough House is a house in which a whole lot of kids live, looked after by a father figure, Lamb. And they all want Lamb’s love, but they also don’t, really, and they also feel rejected by the other house they used to live in — the other parent, the mother. And into that world of needing to be noticed and needing to be accepted, which we all feel, is why Slow Horses is a great series. This season seems to be increasingly focused on family. David’s losing his marbles, the one father figure is losing his marbles. Another father figure, Lamb, is still there. And then this [other] father figure comes in. So something about the introduction of Frank into Slow Horses focuses our attention on what Slow Horses is actually about. And I think it’s really fascinating.

Can you give us a teaser of what’s to come?

River gets kidnapped… We already know that he’s been put in a boot of a car. He gets taken to this place by Patrice, the robotic killer. The beginning of episode six is the most fantastic thing. There’s a great deal of tension going on because there’s a ticking time bomb element to it, but there’s also a desire for Frank to want to take River with him. It’s a preposterous offer for River, but it’s an extreme proposition from Frank.

It’s thrilling. They’re great scenes. They’re really, really pleasurable scenes to have done, to have performed. They were great scenes to explore, and for a viewer, I think it works. I think it’s a fantastic season. It’s a great way to end the season.

How has it been working with this cast? It must be cool to see a great like Gary Oldman at work.

Well, I didn’t have any scenes with Gary at all, unfortunately. We were going to be on set for about two days in a row, I think we were working on the same set, but Gary got COVID at that time, and they had to reschedule his scenes. So I never even got to meet him, but hopefully I will be meeting him.

I loved working with Jack. I’ve worked with Jack quite a lot, and also with Naomi who plays Molly Doran, I worked with her a bit and she’s lovely. Tom Wozniczka, who plays Patrice, and Kristen Scott Thomas, there’s a scene in episode six, which was fabulous to do with her, too. So it was a great pleasure to meet all those lovely actors and to work with them. Ruth Bradley — fabulous, wonderful addition. Again, a great character. I had a really enjoyable time working on the series. It’s a very well-oiled machine, but it’s a very good natured, human machine as well. A lovely set to be on.

Slow Horses releases its sixth and final episode on Apple TV+ on Oct. 9.