Ducker announced the sad news in a Facebook post on Sunday, November 1, 2026.
“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.
Born in Leicester in 1943, Leeson trained at the Royal Academy of Dramatic Art (RADA) before building a career across television, theatre and voice acting.
He became best known for voicing K9, the Doctor’s robotic companion, who first appeared in the 1977 Doctor Who story The Invisible Enemy alongside Tom Baker’s Fourth Doctor.
Leeson brought the character to life with his distinctive voice and witty delivery. Although producers initially planned K9 as a temporary character, his performance helped secure the robot dog’s place as a popular member of the TARDIS crew.
He continued voicing K9 in subsequent seasons and returned for several spin-offs and appearances, including K-9 and Company, The Sarah Jane Adventures and the revived Doctor Who series.
Away from the BBC science-fiction favourite, Leeson appeared in numerous television productions, including Dad’s Army, Blake’s 7 and ‘Allo ‘Allo!. He also played the original Bungle in the children’s programme Rainbow.
Former Doctor Who showrunner Russell T Davies paid tribute to Leeson, praising his performance and describing him as a true gentleman.
“A true gent, and a great loss. Sympathy to his family and friends. Good night, sir. Affirmative!” he wrote.
His death marks the loss of a much-loved performer whose voice helped make K9 an enduring part of Doctor Who history. Leeson leaves behind his wife, Judy Griffiths, and their son, Guy.