John Leeson, the British actor whose clipped and characterful delivery brought the robotic dog K9 to life in Doctor Who, has died at the age of 83. His son, the filmmaker Guy Ducker, confirmed the news in a social media post, stating that his father pᴀssed away peacefully at 3:03 pm on Sunday, 1 November 2026, after a summer of illness.

Born John Ducker in Leicester in March 1943, Leeson trained at the Royal Academy of Dramatic Art in the early 1960s. He adopted the stage name John Leeson and built a long career across theatre, television, radio and voice work. Early credits included appearances in classic British series such as Dad’s Army and The Spanish Farm, and he was the original performer of Bungle the Bear in the children’s programme Rainbow.

His most famous role arrived in 1977 when he first voiced K9 in the Doctor Who story The Invisible Enemy, alongside Tom Baker’s Fourth Doctor. The mechanical dog was originally planned as a temporary character, yet Leeson’s performance — precise, slightly superior, wry and oddly endearing — helped turn K9 into one of the series’ most popular companions. He continued in the role through the late 1970s and into the early 1980s, later returning for anniversary specials, the revived series under Russell T Davies, The Sarah Jane Adventures, the spin-off series K9, and many Big Finish audio productions. He also provided a Dalek voice in Remembrance of the Daleks and played the character Dugeen in The Power of Kroll.

Russell T Davies, who brought K9 back into the series in 2006, paid a warm tribute. He said there had never been any question of asking anyone else to voice the character, describing Leeson’s work as “a fine, fine” performance. Davies characterised K9 as “a posh dog, uppity, haughty, wry, but somehow innocent too, and so funny,” and noted how effectively the voice was pitched so that children could imitate it. He recalled occasional phone conversations with Leeson and described him as a true gentleman who remained dedicated to the role across six decades.

Outside the world of Doctor Who, Leeson’s television work included roles in Blake’s 7, The Bill, Doctors, Crown Court, Vanity Fair and Longitude. He was also a regular continuity announcer for Channel 4. In more recent years he reunited with Tom Baker for the audio drama series Sir Sherlock, in which he played Dr John Watson opposite Baker’s Sherlock Holmes.

Leeson is survived by his wife, Judy Griffiths, a former BBC ᴀssistant whom he married in 1969, and their son Guy. In announcing his father’s death, Guy Ducker quoted Shakespeare’s Hamlet — “Good night, sweet prince, and flights of angels sing thee to thy rest” — and separately thanked Doctor Who fans for the affection they had shown his father over many years.

John Leeson’s voice became inseparable from one of Doctor Who’s most recognisable companions. Through decades of appearances on television and in audio dramas, he helped create a character that was simultaneously mechanical and oddly human — loyal, dry-witted and enduringly popular with generations of viewers. His contribution remains a lasting part of the programme’s history.