John Leeson

John Francis Christian Ducker (born on 16 March 1943 ) better known by his stage name John Leeson, voiced K9 from 1977-1979 and again from 1980-2010 on Doctor Who, K9 and Company, The Sarah Jane Adventures and K9. He provided other voice-over roles on television and for Big Finish Productions and Magic Bullet Productions, and also reprised K9 for Big Finish and BBV Productions.

He also appeared on screen as Dugeen in the season 16 television story The Power of Kroll and as Anthony in the Reeltime Pictures spin-off video Downtime.

Tom Baker detested the character of K9, but got on very well with Leeson. A favourite joke during filming breaks was for Baker to work out crossword puzzles, asking the K9 prop the clues with Leeson giving the answers in character.

Leeson himself became frustrated with the character. He left the programme after the conclusion of the 16th season in 1978. David Brierley took over for four stories (one of which was never completed due to a BBC strike) the following year. When John Nathan-Turner took over as series producer for season 18 in 1980, he tempted Leeson back, with the promise the character would be "killed off" that year. Although the character was, eventually, not killed off, merely written out, Leeson agreed to return, and portrayed all of K9's subsequent return appearances on Doctor Who and its spin-off shows.

Other credits include appearances in Blake's 7 (the Season A episode "Mission to Destiny" and the Season B episode "Gambit"), in which he played the giant Biggum, who was so tall only his feet were seen and his voice heard,,  and Bungle in the children's television series. Leeson is also the voice behind the characters on Children's UK.

Today, he is now most likely to be heard as continuity announcer on Channel 4 in Britain. He also contributed to the charity reference book Behind the Sofa: Celebrity Memories of Doctor Who.

Doctor Who

 * The Invisible Enemy - K-9/the Nucleus
 * The Sun Makers - K-9/Computer (uncredited)
 * Underworld
 * The Invasion of Time
 * The Ribos Operation
 * The Pirate Planet
 * The Stones of Blood
 * The Androids of Tara
 * The Power of Kroll - Dugeen
 * The Armageddon Factor
 * The Leisure Hive
 * Meglos
 * Full Circle
 * State of Decay
 * Warriors' Gate
 * The Five Doctors
 * Remembrance of the Daleks - Dalek Battle Computer/TV Announcer
 * School Reunion
 * Journey's End

Mini-episodes

 * Merry Christmas Doctor Who
 * Dimensions in Time

K9 and Company

 * A Girl's Best Friend

The Sarah Jane Adventures

 * Invasion of the Bane
 * The Lost Boy
 * The Mad Woman in the Attic
 * The Wedding of Sarah Jane Smith
 * Mona Lisa's Revenge
 * The Gift
 * The Nightmare Man
 * Goodbye, Sarah Jane Smith

Mini-episodes

 * From Raxacoricofallapatorius with Love

K9

 * Regeneration
 * Liberation
 * The Korven
 * The Bounty Hunter
 * Sirens of Ceres
 * Fear Itself
 * The Fall of the House of Gryffen
 * Jaws of Orthrus
 * Dream-Eaters
 * Curse of Anubis
 * Oroborus
 * Alien Avatar
 * Aeolian
 * The Last Oak Tree
 * Black Hunger
 * The Cambridge Spy
 * Lost Library of Ukko
 * Mutant Copper
 * The Custodians
 * Taphony and the Time Loop
 * Robot Gladiators
 * Mind Snap
 * Angel of the North
 * The Last Precinct
 * Hound of the Korven
 * The Eclipse of the Korven

Specials

 * The Weakest Link: Doctor Who Special
 * Pointless Celebrities: Doctor Who Special
 * K9's Question Time

Direct-to-video

 * Downtime - Anthony

Webcasts

 * Shada

Video games

 * LEGO Dimensions

Big Finish Monthly Range

 * Zagreus
 * Revenge of the Swarm - the Nucleus/Computer

Big Finish Special Releases

 * Shada

Fourth Doctor Adventures

 * The Sands of Life
 * Phantoms of the Deep
 * The Dalek Contract / The Final Phase
 * The Exxilons
 * Requiem for the Rocket Men
 * Death Match
 * The Fate of Krelos / Return to Telos
 * Wave of Destruction
 * The Paradox Planet / Legacy of Death - K-9/Machina
 * The Trouble with Drax - K-9/Drax
 * The Pursuit of History / Casualties of Time
 * The Beast of Kravenos
 * The Eternal Battle
 * The Silent Scream
 * The Mind Runners / The Demon Rises
 * Planet of the Drashigs
 * The False Guardian / Time's Assassin
 * Fever Island
 * The Perfect Prisoners
 * Purgatory 12
 * Chase the Night

Novel Adaptations

 * The Romance of Crime
 * The English Way of Death
 * The Well-Mannered War

Companion Chronicles

 * The Time Vampire

Gallifrey

 * Weapon of Choice
 * Square One
 * The Inquiry
 * A Blind Eye
 * Lies
 * Pandora
 * Insurgency
 * Imperiatrix
 * Fractures
 * Warfare
 * Appropriation
 * Mindbomb
 * Panacea
 * Reborn - K9/Tallan
 * Disassembled
 * Annihilation
 * Forever - K9/The Krilig
 * Arbitration
 * Ascension - K9/Tallan

Kaldor City

 * Storm Mine - Chief Mover

Adventures in a Pocket Universe

 * The Choice
 * The Search

Audiobook Readings

 * Doctor Who and the Ribos Operation
 * The Stones of Blood (K9 voice)
 * Peculiar Lives
 * Shada (K9 voice)
 * The Androids of Tara
 * The Adventures of K9
 * Full Circle (K9 voice)
 * K9 and Company
 * Doctor Who and the State of Decay (K9 voice)
 * Doctor Who and the Invasion of Time
 * Doctor Who and the Invisible Enemy
 * Doctor Who and the Sunmakers (K9 voice)
 * Warriors' Gate (K9 voice)
 * Doctor Who and the Armageddon Factor

Documentary

 * Where on Earth Is... Katy Manning Because She'd Really Like to Know!
 * K9 Unleashed
 * A New Beginning
 * Friends Reunited
 * Parrot Fashion
 * Getting Blood from the Stones
 * A Matter of Time
 * Celebration
 * Dreams and Fantasy
 * Out of Time
 * The Vampire Lovers
 * The Dreaming
 * All Aboard the Starliner
 * The Doctors Revisited - The Fourth Doctor
 * Toby Hadoke's Who's Round

Other

 * Blue Peter 1977 & 2006
 * Myth Runner
 * My Life: I Am Ethan
 * The Five(ish) Doctors Reboot
 * Doctor Who Live: The Afterparty