John Leeson, who has died aged 83 following a long illness, was a prolific actor on stage and screen with a career spanning seven decades.
Born John Francis Christopher Ducker in 1943 in Leicester, John Leeson graduated from the Royal Academy of Dramatic Art (RADA) in 1964 and began his acting career that same year, playing Gibbet in The Beaux' Stratagem at the Colchester Repertory Theatre. He made his television debut the following year in Meeting Point. Other notable television programs he appeared in include Crossroads, Dad's Army, Blake's 7, Jigsaw, The Bill, and Doctors.
He joined the Whoniverse in 1977, when he voiced both the Nucleus and K9 in The Invisible Enemy. He went on to reprise the role of K9 many times since then, in Doctor Who, K-9 and Company, K9 and The Sarah Jane Adventures as well as in Big Finish audio dramas. And all that despite refusing to appear in season 17 (1979–80) due to being frustrated by the character. K9 was then voiced by David Brierley. Leeson returned for season 18 and regularly reprised the role until his death.
However, his Whoniverse career doesn't stop there. Leeson also voiced the computer in The Sun Makers (1977) and the Renegade Battle Computer in Remembrance of the Daleks (1988). Furthermore, he made two live-action appearances, as Dugeen in The Power of Kroll (1978–79) and Anthony in Downtime (1995). Finally, he was an uncredited "We wish you a merry Christmas" performer in K-9 and Company.
He recently reunited with his Doctor Who co-star Tom Baker in the audio series Sir Sherlock in which Leeson voices Doctor Watson and Baker voices the titular detective. Some episodes will be released posthumously.
He is survived by his wife, former BBC assistant Judy Griffiths, and their son, filmmaker Guy Ducker.
● John Leeson (John Francis Christopher Ducker), actor, born 16 March 1943; died 1 November 2026
All information in this article was carefully compiled from reliable sources.