Season 4 of “Slow Horses,” which aired in the fall of 2024, was a showcase for former MI5 officer David Cartwright, the grandfather of agent River Cartwright and a man whose murky past in the espionage service included enough underhanded dealings to have earned him the nickname “the Old Bastard.” Played by the formidable Jonathan Pryce, David appeared in most of the season’s episodes and played a crucial role in River’s discovery that his father was a brilliant and deadly mercenary, all while succumbing to dementia to the point that he was taken to a care facility against his will.
But when Apple TV dropped Season 5 in September 2025, David was almost entirely absent, apart from a phone call in Episode 5 and a scene in the sixth and final episode where his ramblings about bees gave River the key to an attack that was about to happen. Pryce’s role was smaller than ever, but he made it pay with a wrenching yet ultimately hopeful portrayal of a man whose affliction doesn’t prevent him from finding moments of pleasure and making a pivotal contribution to foiling a Libyan terrorist plot.
You would expect nothing less from Pryce, a 79-year-old Welsh actor whose work includes a Tony-winning performance in the play “Comedians,” film roles that range from Terry Gilliam’s cult classic “Brazil” to the recent “The Two Popes” and a memorable two-season arc on “Game of Thrones.”
“I just wanted to show people that he was happy and content,” Pryce said of the “Slow Horses” scene with Jack Lowden, who plays River. “I got quite upset watching the scene (in Season 4) where they put him in a care home, because I was looking at it thinking, That could be me. It would’ve been a nightmare if we’d gone back to the care home and he was in distress. I wanted to see it resolved in a positive way, because it’s a subject that is very dear to my heart.”
Pryce, an ambassador for the Alzheimer’s Society who has a family member with dementia, has played characters with the condition three times in recent years: in the Florian Zeller play “The Height of the Storm,” in “Slow Horses” and in the 2025 Chris Columbus film “The Thursday Murder Club.”
“I know the power when people with any kind of disability or illness are portrayed in a sympathetic way on screen,” he said. “It’s a great way to educate people to be more compassionate.”
But when he took the role in “Slow Horses” — which is based on a series of novels by Mick Herron about a group of disgraced agents exiled to the disreputable Slough House, run by the surly and flatulent Jackson Lamb — he didn’t know that the dementia storyline was coming.
“I purposefully didn’t read the books because I wanted to discover things as they were evolving,” he said. “I wasn’t thinking ahead with the character, trying to fulfill something that I knew would eventually happen to him. The audience discovers things at the same time as I discover them, and I find that a very satisfactory way to work.”
Still, David Cartwright is a mysterious character whose past remains murky to the audience, except when Gary Oldman’s Lamb occasionally blasts him for past misdeeds. And while Pryce didn’t mind being in the dark about David’s future, he did talk to creator Will Smith about that hidden history.
“I needed to know certain elements of his past,” he said. “In the books he is called the Old Bastard, and he is a horrible man. But I didn’t want to play him as a bastard. He’s a man who thinks his behavior is the correct behavior. And if his job meant killing someone, then he did his job well.”
He played the character as benign, laying the groundwork for scenes with Lamb. “I think it makes really interesting drama, the juxtaposition of the person that the audience is very sympathetic toward, and then suddenly Jackson was taunting him and revealing the truth about him.”
Asked if it changes his job as an actor when the character begins to forget his own past, Pryce laughed. “My job does change,” he said. “It becomes easier. You have a simple line to follow. There are none of the complexities. You’re free of the past in a way, and there’s almost no filter anymore.”
The role, he said, is one of his most rewarding in a career that began on stage in the 1970s and got its first big boost with the 1975 Trevor Griffiths play “Comedians.” He won his Tony when the show moved to Broadway in a production directed by Mike Nichols. In its aftermath, he followed his agent’s advice, headed to Los Angeles for a series of meetings “and very quickly realized it wasn’t for me.”
He laughed. “I took meetings with some of the strangest people you’d ever want to meet. But they probably thought I was pretty strange, too, because I’d come from playing a skinhead, so I had my head shaved and I was very political at that time. I couldn’t see how I was going to fit in.”
He felt more comfortable in projects like Terry Gilliam’s “Brazil,” a black comedy in which he plays a low-level bureaucrat in a dystopian future society. “It was the most wonderful experience making that film, and it’s most gratifying now in that it still finds a new audience,” he said. “A vast number of the middle-aged directors I work with say they were inspired or they got into film through ‘Brazil.’ I say, ‘So what took you so long to give me a job?’”
In recent years, his most high-profile job was “Game of Thrones,” another project that found him determined not to look at what lay ahead: He started by reading the scripts for Season 5, in which his character, the High Sparrow, initially appears to be a zealous religious leader devoted to helping the poor and bringing morality to King’s Landing.
“Ironically, I based the character on Pope Francis, because the High Sparrow was caring for people, thinking about the poor, being very positive about the disenfranchised,” he said. “I played him as a good man.”
Then he read the scripts for Season 6, with the brutally intolerant character forcing Cersei Lannister on a nude “walk of shame” through the streets of the city before she incinerates him in a horrifying act of payback. “I was like, ‘Holy s—, this guy’s a monster,’” he said. “But I’m glad that I didn’t know he was a monster.”
Pryce got to play Pope Francis for real in the 2019 drama “The Two Popes” with fellow Welshman Anthony Hopkins (“working with Tony was an absolute joy”), and he speaks glowingly of making low-budget indies like the upcoming “It’s All Going Very Well…” with Tilda Cobham-Hervey.
“There are odd days when I think, ‘What the fuck am I doing?’” he said with a shrug. “People ask me what I’m working on, and I found myself recently saying, ‘I’m playing this old Welsh hill farmer,’ and I realized the word old is redundant.”
A laugh. “If I’m playing him, you don’t need to say he’s old. You know it. But I still enjoy it.”
A version of this story first appeared in the Drama Issue of TheWrap’s awards magazine. Read more from the issue here.
