John Leeson, the Voice of Doctor Who’s K9, Dies at 83. He Was Asked to Sound Like a Speaker in a Cheap Radio
John Leeson, the English actor who gave Doctor Who’s robot dog K9 his clipped, know-it-all voice from 1977, has died at 83. His son announced on Sunday that he died peacefully after what the family called a summer of illness. Leeson voiced K9 for more than three decades, across the original series, its revival, two spinoffs, audio dramas and a video game.
His son, Guy Ducker, shared the news in a Facebook post on Sunday, 1 November. “I regret to announce the death of my father, John Ducker, a.k.a. John Leeson, at 3:03pm today after a summer of illness. The end was peaceful,” he wrote, closing with a line from Hamlet: “Good night, sweet prince, And flights of angels sing thee to thy rest.”
Leeson was born John Francis Christopher Ducker in Leicester in March 1943 and trained at the Royal Academy of Dramatic Art. He’s survived by his son and by his wife, Judy Griffiths, whom he married in 1969.
Hear the voice: John Leeson as K9 in “School Reunion” (2006). The clip starts just before K9 speaks. Video: Doctor Who, BBC Studios, on YouTube
Asked to sound like a cheap radio
K9 first rolled on screen beside Tom Baker’s Fourth Doctor in “The Invisible Enemy” in 1977. Leeson got the part before the prop had even been built. In a 2014 interview, he remembered going to see producer Graham Williams and being shown the blueprints, with a tartan collar drawn round the dog’s neck.
“I said, ‘Well, do you want him Scottish?’ and he said, ‘Oh no, heaven forfend, we don’t want Scottish,'” Leeson said. Williams wanted something else entirely. “He’s an absolute know-all, but we want his voice to sound as if it comes out of a tiny little elliptical speaker in a cheap radio.”
VoiceEditSuiteRate CalculatorKnow what to charge before you reply.Low, mid and high pricing in a ready-to-send quote.See how it worksSo Leeson recorded a few voices on tape and sent them in. He assumed he was one of many in line for the job, and only learned later that the BBC had wanted him all along. The voice he settled on was his own, pitched up and clipped. “It couldn’t sound like a dog, because K9 isn’t a dog, but I made it sound as mechanical as possible,” he told the interviewer, in remarks Bleeding Cool republished on Sunday.
Williams liked the character so much that K9 stayed on as a regular companion, partly to win over younger viewers. Baker reportedly couldn’t stand the dog, but he got on well with the man voicing it. When Leeson turned up on Baker’s edition of This Is Your Life in 2000, he made his entrance on all fours.
The voice actor who walked away, and came back
For working voice actors, the most familiar part of Leeson’s story may be the moment he left. He worried that being heard but never seen would hurt his chances of other work, and he stepped away from the show after the 16th season in 1979. He did get one on-screen role in that run, playing Dugeen in “The Power of Kroll.”
David Brierley voiced K9 for the following season, and the script explained the change of voice as a case of laryngitis. When John Nathan-Turner took over as producer in 1980, Leeson agreed to come back for the dog’s final run of stories before K9 was written out.
Image: Mark Healey, CC BY-SA 2.0, via Wikimedia Commons
Written out didn’t last. Leeson voiced K9 in the 1981 pilot K-9 and Company, which never went to a series, and in a cameo for the 20th anniversary special “The Five Doctors.” Through the 2000s he kept the voice alive in audio, in plays for BBV and in Big Finish dramas such as Zagreus and the Gallifrey series, later joining Louise Jameson, Mary Tamm and Lalla Ward in Big Finish’s Fourth Doctor Adventures.
Back for a new generation
The revived series brought K9 home in 2006’s “School Reunion,” with Elisabeth Sladen back as Sarah Jane Smith, and it was Leeson’s voice that came out of the battered tin dog. A younger audience then got to know him through The Sarah Jane Adventures and through K9, a separate series built around the original model of the dog.
Image: williamsdb, CC BY-SA 2.0, via Wikimedia Commons
He was heard as K9 again in “Journey’s End” in 2008, the last of his Doctor Who episodes, and his recordings were used in the LEGO Dimensions video game in 2015. Leeson also voiced the Nucleus in “The Invisible Enemy” and a Dalek in “Remembrance of the Daleks,” so his range on the show went well beyond one machine.
Few voice roles stay with one actor for that long, through changes of producer, broadcaster and medium. Leeson outlasted several Doctors, and his was still the voice fans expected to hear from the dog.
Far more than one robot dog
Before K9, Leeson was the first actor inside the Bungle costume on the children’s programme Rainbow in 1972, and on BBC children’s television he voiced Jigg and played the giant Biggum in Jigsaw. He worked on stage in the West End in Neil Simon’s Plaza Suite in 1969, and on television in Dad’s Army, Blake’s 7, Sorry!, ‘Allo ‘Allo!, The Bill and Doctors.
Image: James Dimelow, public domain, via Wikimedia Commons
Alongside the acting he built the kind of steady voice career most listeners never notice. He worked as a freelance continuity announcer for BFBS Television in Germany, the BBC and Channel 4, read extensively for the Calibre Audio Library, which records books for people with sight loss, and narrated The Space Gypsy Adventures for children’s hospital radio.
He was still working this year. In 2026 he played Dr. Watson opposite Tom Baker’s Sherlock Holmes in Sir Sherlock, an audio drama funded on Kickstarter, putting the two old TARDIS travellers back in a studio together nearly 50 years after they first met.
Sources: Bleeding Cool (Ray Flook, 1 November 2026, quoting Guy Ducker’s Facebook post and a 2014 interview with John Leeson); Wikipedia entries for John Leeson and K9 (career credits). Images: Mark Garland (hero, Gallifrey One 2011, CC BY-SA 2.0), James Dimelow (public domain), williamsdb (CC BY-SA 2.0) and Mark Healey (CC BY-SA 2.0), via Wikimedia Commons.
Lee este artículo en español: Muere John Leeson, la voz de K9 en Doctor Who, a los 83 años. Le pidieron que sonara como el altavoz de una radio barata
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