Kristin Scott Thomas on ‘Slow Horses’ Season 4, Maggie Smith, more

Ten years ago, when asked if she had considered following Maggie Smith from “Gosford Park” (in which they both starred) to “Downton Abbey,” Kristin Scott Thomas could not have been more clear: She had no interest in television.

“It just goes on and on,” she told the Guardian. “I get terribly bored. Series bore me.”

Five years later, she mercifully changed her mind.

Not about “Downton Abbey” — “I do not regret anything with a corset” she says now — but about television. First with “Military Wives” and a brief yet spellbinding appearance in “Fleabag,” but most importantly with “Slow Horses,” in which she plays MI5 second-in-command Diana Taverner alongside Gary Oldman’s sidelined but still tricky operative Jackson Lamb.

There are few cinematic experiences as exquisite as watching Scott Thomas face off with Oldman. Or anyone else, for that matter.

And after two years of critical raves, a devoted fan base and oddly muted marketing, “Slow Horses” ends its fourth season on Apple TV+ on Wednesday as the show everyone is talking about. Including Scott Thomas.

“I’m watching it as if I weren’t in it,” she says during a recent interview over Zoom. “The plots are so complicated and have so many twists and turns, I get completely lost. ‘Oh right, I forgot that happens.’ It is thrilling to watch and really enjoy it — like, ‘this is really good.’”

She didn’t even ask for screeners — she watches it weekly like everyone else. Which she thinks is more engaging than a full-season drop. “Tension builds, discussions happen,” she says. “The other day I went to a dinner with media company owners and all they wanted to know was about ‘Slow Horses.’”

There are many things to love about the series, but Scott Thomas’ performance as Taverner is among the top three. As she has so often done over a long and varied career, the actor regularly steals every scene she’s in, occasionally out from under even Oldman’s deplorable footwear. While everyone around her is losing their heads, her Taverner can look directly into the roiling abyss and calculate a way, if not to fix it, then certainly to cover it up.

As it turns out, no actor living can do blasé ruthlessness better than Kristin Scott Thomas.

Though much has been made of the clash-of-the-titans chemistry she has with her former “Darkest Hour” co-star, Scott Thomas says she didn’t know Oldman would be starring when she signed on. “They just said they were looking for someone big.” Neither had she read the Mick Herron novels on which the series is based.

What lured her, she says, was the “excellent writing [and] fascinating characters” of the first episode. “I started to think ‘Well, maybe.’ But,” she adds with a laugh, “I hadn’t figured on ‘Well, four years later, here we are.’ I had only read the pilot and I thought maybe [Diana] died quite quickly or got fired.”

Fortunately for “Slow Horses” fans, that was not the case. Though Scott Thomas will give nothing away about Season 5 (beyond the fact that it is almost finished filming), as we approach the end of the fourth season, Taverner is alive and well and covering up some very messy tracks as fast as she, her fellow spooks and her new boss can make them.

Despite Season 3 ambitions that she would replace Ingrid Tierney (Sophie Okonedo) as head of MI5, Taverner now reports to the weaselly Claude Whelan (James Callis), who was brought in, ostensibly, to bring transparency to the agency.

Taverner is certainly not the hero of “Slow Horses.” Over three seasons she has done many despicable things and made it very clear that she is more than willing to sacrifice Lamb and his group of misfit agents if it will keep her out of trouble.

Still, it’s difficult not to root for her, now more than ever. While the A-plot of this season has been River Cartwright’s (Jack Lowden) attempt to find out why someone tried to kill his grandfather, former MI5 head Richard Cartwright (Jonathan Pryce), the B-plot follows Taverner’s frustration with the tragically underqualified Whelan, a dynamic that anyone who has ever had to train their new boss will certainly recognize.

“The rage of being over-passed, that’s what keeps her going during this season,” Scott Thomas says. “She is much better at it than anyone else and she should have the job. The reason she doesn’t is because she’s older, she’s a woman, and no one ever listens to older women. So I’m flying the flag of older women. Come on, we have experience. Listen to us.”

Whelan, even more than Lamb, has tested Taverner’s patience this season, which has been a challenge for Scott Thomas, who is so invested in keeping her character calm, cool and collected that from the first she has demanded a no-profanity policy for Taverner.

Originally, she says, “there were rude words all over the place and I got them to remove them. I said, ‘No, no, no, we can’t have her swearing like that.’” Taverner is icy “so when she does screw up, something slips out, it’s a sort of embarrassment — using the words of common people.”

Even so, Scott Thomas does not take full credit for Taverner’s unflappable demeanor; much of it, she says, comes down to directing. She describes shooting a scene in which Taverner is irritated by someone who then leaves her office. “The camera’s on me, and I’m doing all this sighing and eye-rolling, having a great time and thinking ‘God, you’re really good.’ And the director comes up to me and says ‘Um, could you just keep it really still?’”

She laughs and adds that though Taverner is usually allowed one outburst each season, “when I’m working with James, who’s hilarious, it’s very difficult to contain my disdain and frustration. Somebody has to reign me in quite a lot and remind me I’m Diana Taverner, not me.”

As “me,” Scott Thomas has been remarkably outspoken about her love/hate relationship with Hollywood. In the years after starring in hits including “The Horse Whisperer,” “Four Weddings and a Funeral” and “The English Patient,” she stepped away from her English-speaking film career at least twice to focus on French films (she lives in Paris) and the stage.

More recently, she has pointed out the obstacles faced by female performers as they age. In 2020, she told the Radio Times she was “fed up of having to say thank you whenever someone says I’ve ‘still got it.’” Though her character in “Fleabag” famously rhapsodized the postmenopausal life, for female actors, she says, the reality can be a bit less glorious. “You get to 60 and it’s slim pickings. It’s still a beauty-based business and that’s a really tough pill to swallow. I enjoy having life written on me, I’m proud of it, but it’s limiting. So what do you do? Rush off and risk your life on the surgical table?”

The “Fleabag” role was, she says “a stroke of complete blissful luck. Out of the blue, never met her, I got a phone call from Phoebe Waller-Bridge asking, ‘Do you want to do this?’ and I said, ‘You have to be kidding, of course I will do this, I will do this now.’”

Gary Oldman, left, wasn’t yet cast to play Jackson Lamb when Scott Thomas signed on to “Slow Horses”: “They just said they were looking for someone big,” she says.

(Apple)

The monologue wasn’t as easy to film as it looked, however. “It was brilliant but it was very difficult because it’s written in a very specific Phoebe Waller-Bridge style. She’s very specific about her phrasing; she’s particular about everything. I could never remember if it was built-in pain or in-built pain and we would have to stop the take every time. But I really enjoyed working with her, she’s so clever.”

It was also yet another departure from the silo of elegant but wounded women who at different times threatened to overtake her Hollywood career. Even when she was cast in “Gosford Park,” she was disappointed to learn she would be playing Lady Sylvia McCordle; she would have preferred being below stairs.

“When [the script for] ‘Gosford Park’ arrived,” she says, “I remember thinking as it plopped through the letterbox, ‘Robert Altman; at last he’s found me.’ I thought, ‘Hooray,’ he’s going to give me a role as a maid.’ And then no, I got the role of an aristocrat. With a fur.”

Not that she regrets taking the role; working with Altman was everything she had dreamed it would be. “He was an amazing master of directing actors. We’d have two cameras in all those big scenes and he would stand there, incredibly tall with beautiful long fingers and wave his arms around like a conductor.”

It was an enormous and intimidating cast — Maggie Smith, Michael Gambon, Helen Mirren, Eileen Atkins, Charles Dance, Derek Jacobi, to name a few — but that didn’t faze Altman.

“Once,” Scott Thomas says, “something wasn’t going quite right and he said, ‘Gather round, gather round.’ We all gathered round — Dame this, Dame that, Sir this, Sir that, all these incredible people of the British acting world waiting like Labradors — and he said, ‘One of you is the weakest link’ and just left. We all wondered, ‘Is it me, is it me?’ and we all sharpened up.”

Including Smith, whose recent death sparked an international outpouring of grief and memories. “She was so funny,” Scott Thomas said, “and she was a fantastic giggler. [In one dinner scene], she was sitting at the top of the table with Michael Gambon and they were doing improv and she could not stop giggling. She was literally hanging onto the table because she knew the camera was about to arrive.”

Scott Thomas worked frequently with Smith, and with her ability to deliver a devastating line with a raised eyebrow and a haughty expression she may be Smith’s most obvious successor, a comparison Scott Thomas finds “beyond complimentary.”

“I think I played her daughter or niece four times. She was just astounding physically. She was so beautiful and regal and had the most amazing hands and this very, very still face that would suddenly burst into these giggles and twinkles and then recompose and you never knew what you were going to get.”

From Smith, Scott Thomas says she learned the importance of preparation and training.

“You’ve got to know your stuff before you can have fun. She was incredibly disciplined in work, always knew her words backwards, knew the cues. I don’t think I’ve ever met anyone with such imagination on how to read a line. At same time she was impatient with modern ways, the mumbling or ‘I’ll just do that again.’ She couldn’t stand all that.”

In one project, Scott Thomas remembers a “poor unfortunate actor” who kept ad-libbing, trailing off his lines so Smith couldn’t pick up her own cue. “He wouldn’t stop acting and she said, ‘Just cough when you get to the end of your line and I’ll know when to say mine.’”

Scott Thomas recently made her own directorial and writing debut with “North Star,” a semi-autobiographical film about a trio of sisters, played by Scarlett Johansson, Sienna Miller and Emily Beecham, who reunite for their mother’s third wedding; Scott Thomas plays the mother, Diana.

“I loved all my actors and telling a very sweet English story about what’s your name and who’s your clan,” she says. “Didn’t love acting with myself as a director,” she says with a laugh.

The film received mixed reviews, but Scott Thomas believes that artists and “the powers that be need to be braver and not just feed us what they think we want to see. We’re artists, we need artistic creativity, we don’t need ‘product’ that just gets launched. Sometimes you’re going to get a flop, sometimes you’re going to get a jewel. Like ‘Baby Reindeer.’ You can love it or hate it, but it was brave.”

Ironically, her decision to commit to television, or as she and many others call it, “long form,” has allowed Scott Thomas the freedom to begin directing, and many other things; in March she made her runway debut, walking for Miu Miu during Paris Fashion Week. “I did a bit of fashion,” she says. “I did a play last year, ‘Lyonesse,’ that broke 23 box office records. I did a reading of Kafka stories for his 100th anniversary.”

Then, she says, she gets to come back and find her “Slow Horses” mates and “know you are making something that is destined for a vast audience that is incredibly high quality and is just unifying in so many ways.”

“That’s what we want to do — tell stories for people to be engrossed by and if they are engrossed, then job done.”