Tim Pigott-Smith, an acclaimed British character actor who in the 1980s vaulted to fame on television in “The Jewel in the Crown” and who more recently won accolades playing the title role in the West End and Broadway productions of “ King Charles III ,” died on Friday in Northampton, England. He was 70.

His death was confirmed by his agent, John Grant, who said the cause was not immediately known.

Mr. Pigott-Smith, who lived in London, had been in Northampton rehearsing the role of Willy Loman for a British touring revival of “Death of a Salesman,” which was scheduled to begin on Monday at Royal & Derngate .

He had recently completed “ Victoria and Abdul ,” a film starring Judi Dench that is scheduled for release this fall, as well as a television adaptation of “King Charles III.”

Mr. Pigott-Smith, 6 feet tall with blue eyes and fair hair, was a patrician figure with classical training who worked constantly on stage, film and television, mostly as a performer, but also as a director. This year he was awarded the Order of the British Empire by Queen Elizabeth II for his services to drama.

His work in “The Jewel and the Crown,” a 1984 mini-series set in India during the British Raj, was recognized with a BAFTA award , Britain’s equivalent of an Academy Award; his performance in “King Charles III” ? which imagines Prince Charles succeeding his mother as the British monarch ? was nominated for both Olivier and Tony awards.

“He was a funny mix, because he was really bright, very educated; he almost felt like an English private-school master,” said the British director Rupert Goold, who had known Mr. Pigott-Smith since childhood (he had been driven to school by Mr. Pigott-Smith, who had a child in the same school) and who directed him in “King Charles III.”

“He also had a silly, playful, mischievous side,” Mr. Goold said. “He enjoyed joining in dancing, or crazy warm-ups.” An example, he said, was a decades-long prank Mr. Pigott-Smith had played with Ms. Dench, in which each tried to slip a black glove into productions featuring the other.

Timothy Peter Pigott-Smith was born on May 13, 1946, in Rugby, England. His mother was an amateur actor and his father was a journalist. His enthusiasm for the theater was intensified when his father became editor of a newspaper in Stratford-upon-Avon; the young Mr. Pigott-Smith went to see as much Shakespeare as he could.

He studied drama at the University of Bristol and the Bristol Old Vic Theater School, and then began work at the Bristol Old Vic as an assistant stage manager, occasionally playing small parts, there and around the country .

He made his West End debut in 1971, as Laertes in “Hamlet,” and then joined the Royal Shakespeare Company. He made his Broadway debut in 1974, as Doctor Watson in a Royal Shakespeare Company production of “ Sherlock Holmes .” (“Tim Pigott-Smith showed good natured spaniel-bafflement as the invaluable Dr. Watson,” the critic Clive Barnes wrote in The New York Times.)

“It was heaven, of course ? absolute heaven,” Mr. Pigott-Smith said in an interview in 2015. “That was the first time I’d been to the States.”

He moved from theater into television in the 1970s and 1980s, peaking with his role as Ronald Merrick, a villainous police superintendent in “ The Jewel in the Crown .”

He also appeared in many movies , among them the original “ Clash of the Titans ,” in 1981, with Laurence Olivier, and, that same year, in a soccer film, “ Victory ,” which he called “one of the world’s great turkeys.”

But when he was offered a television pilot that, if successful, would require him to move to Los Angeles, he decided that he was not interested in celebrity ; he and his wife, the actress Pamela Miles, bought a house in London, and he recommitted himself to the stage.

“I couldn’t think of anything better than doing great plays with great people in a great company,” he said.

He is survived by Ms. Miles, who had been scheduled to appear with her husband in “Death of a Salesman” until she was injured and had to drop out. His survivors also include a son, Tom, and two grandchildren.

In theater, Mr. Pigott-Smith played a wide range of classical and contemporary parts ? from Shaw to Albee ? but with a special emphasis on Shakespeare. In 1999, he played Larry Slade in a Broadway production of Eugene O’Neill’s “ The Iceman Cometh ” led by Kevin Spacey.

He often played villains, and was frequently in supporting roles, which made his casting in “King Charles III,” particularly poignant.

“He had done so much amazing work in TV series and on film and in plays, but he hadn’t carried things as often as he deserved to, so there was something in the role of Prince Charles that spoke to him,” Mr. Goold said. “He also had a passion for new work, and for verse, and for someone to be writing for an actor his age in blank verse ? he was in heaven.”