John Leeson, Voice of Doctor Who's K9, Dies Aged 83

John Leeson, the actor best known as the voice of K9 in Doctor Who, has died at the age of 83, according to The Guardian. His son, Guy Ducker, announced the death on Facebook. Ducker said his father had died after a summer of illness and that the end was peaceful.

Screen Rant reported that Leeson died on 1 November 2026.

Born John Ducker in 1943, Leeson trained at Rada, the Royal Academy of Dramatic Art. He later worked as a continuity announcer on Channel 4 and played Bungle on the children's show Rainbow.

K9, the robotic dog who accompanied the Doctor, was created by Bob Baker and Dave Martin. The character first appeared in the 1977 serial The Invisible Enemy, which starred Tom Baker as the Doctor. K9 was originally intended to feature in a single story, but remained in the series until 1981. David Brierly also voiced K9 for a period. K9's catchphrase to the Doctor was "Affirmative, Master."

Leeson returned to the role in the programme's 20th anniversary special and in the spin-off K-9 and Company, which starred Elisabeth Sladen as Sarah Jane Smith. He and Sladen also reappeared in the 2006 episode "School Reunion," starring David Tennant. Leeson later featured in the CBBC spin-off The Sarah Jane Adventures, which aired from 2007 until Sladen's death in 2011.

At the time of his death, Leeson was still providing the voice of K9 for Big Finish audio dramas.