K9, retroactively "K9 Mark I" (Leeson), initially appeared in The Invisible Enemy (1977) as the creation of Professor Marius (Frederick Jaeger) in the year 5000. K9 subsequently travelled with the Fourth Doctor (Tom Baker) and Leela (Louise Jameson) as a companion of the Doctor in his adventures in time and space until The Invasion of Time (1978). In this serial, K9 decides to remain on the Doctor's home planet of Gallifrey with Leela. Immediately afterwards, Doctor Who would introduce a second incarnation of K9, played by the same prop; the last scene of The Invasion of Time shows the Doctor unpacking a box labeled "K9 Mk II".

This K9 exhibited the ability to sense and warn others of danger. He was also more mobile than his predecessor, despite his problems with the swamps of Delta III, able to lift himself up on small support rods so that he could climb stairs (PROSE: The Shadow of Weng-Chiang, TV: The Power of Kroll, The Armageddon Factor) The Doctor often used a glib remark to disarm those who were surprised by K9's appearance, such as "They're all the rage in Trenton, New Jersey." (TV: The Stones of Blood)
Solid K9 Training, founded by award-winning, internationally-acclaimed dog trainer Jeff Gellman, is one of the nations most effective and respected dog training services providing no-nonsense, "Real World" training methods throughout New England. Serving dog owners from Hartford, CT to Boston, MA in our multifaceted, secure and 24/7 staffed Solid K9 Training Center in Providence, RI, as well as all throughout the nation with Jeff's wildly successful RV Dog Trainer Tour. We will train any dog, regardless of breed, shape, size or history. We work to fix all dog behavior issues including excessive barking, growling, snapping, nipping, dog aggression (fighting), human aggression (biting), child aggression, pulling on leash, leash aggression, leash reactivity, skateboard reactivity, resource guarding, jumping on people, fear issues, anxiety issues, separation anxiety, chewing and destroying household items, running away, not listening, door bolting, stealing food, getting into the trash, cat aggression, chasing game, and killing animals/game. We also have a renowned reputation specializing in obedience training, which includes heeling and walking properly on a leash, sit/stay, down/stay, place, recall training (come to owner), and crate training. Our Training services include Board and Train behavioral modification, 1 on 1 Training, Obedience Classes, Puppy Training programs, Boarding / Board & Play, Daycare, and many free dog training resources including Dog training advice videos, dog training webinars, and Dog Training Q and A videos on Periscope on Monday and Wednesday nights. Our behavior modification training is cutting edge, using techniques like modern low level E-collar (remote collar) training and food and clicker training. Solid K9 Training has a worldwide reputation of being able to handle the most challenging dog behaviors and often times other dog trainers will refer their more serious cases to us. For more information on our services offered, as well as free dog training tutorial videos, please see my website and other social media pages:

He did not use contractions such as "you've" for "you have" and addressed others by titles such as "Master", "Mistress", "Doctor-Master" (to refer to the Doctor) or "Young Master" (Adric, Starkey and in one instance, Clyde). Though he did not seem to resent his subordinate status, he sided with the Doctor's companions over the Doctor and showed a dark side, regarding other artificial intelligences with contempt. (TV: The Invasion of Time, TV: The Wedding of Sarah Jane Smith, TV: Robot Gladiators) He relished a brief chance to act as a figure of power. (PROSE: The Well-Mannered War)


He did not use contractions such as "you've" for "you have" and addressed others by titles such as "Master", "Mistress", "Doctor-Master" (to refer to the Doctor) or "Young Master" (Adric, Starkey and in one instance, Clyde). Though he did not seem to resent his subordinate status, he sided with the Doctor's companions over the Doctor and showed a dark side, regarding other artificial intelligences with contempt. (TV: The Invasion of Time, TV: The Wedding of Sarah Jane Smith, TV: Robot Gladiators) He relished a brief chance to act as a figure of power. (PROSE: The Well-Mannered War)

In 1996, Sarah used K9 to hack into records and find Sam Jones' home address and later to translate Lost Boy's speech. (PROSE: Interference - Book One) K9 was briefly possessed by a malevolent entity, but was freed when Sarah accidentally electrocuted him. (PROSE: The Sow in Rut) K9 began slowly breaking down and eventually ended up deactivated in a cardboard box in Sarah's attic. (PROSE: Moving On) Hilda Winters had K9 dismantled and analysed. (AUDIO: Mirror, Signal, Manoeuvre)


K9 Mark IV was a recreation and enhancement of the Mark III created by the Tenth Doctor as a second present for Sarah Jane. (TV: School Reunion) This model continued in service to his mistress, Luke Smith, Clyde Langer, and Rani Chandra and was known by Maria Jackson and Kelsey Hooper. He was left fixing a black hole in Sweden for many years, but after returning to Earth, was used sparingly, until he went to university with Luke Smith. (TV: The Nightmare Man)
Later he defeated Ahab, who tried to convince him he had murdered Zanthus Pia. He became part of the K9 Unit, being made the responsibility of Gryffen and under the control of Department inspector June Turner. (TV: The Bounty Hunter) He foiled Inspector Drake's plan to control the population using Cerulium (TV: Sirens of Ceres) and experienced fear. (TV: Fear Itself) He aided in the defeat of echoes of Gryffen's family, (TV: The Fall of the House of Gryffen) Orthrus, a duplicate of him created by Drake to frame him (TV: Jaws of Orthrus) and the Bodach. (TV: Dream-Eaters) He met Nehetka and Geb of the Anubians, a race his previous incarnation liberated. He was so obsessed with regaining his lost memories that he didn't notice Gryffen, Starkey and Jorjie's takeover by the Anubians. He soon found out when the Anubians attacked the Department. With Darius' help, he defeated them. (TV: Curse of Anubis)

Our training will give you the best opportunity to be successful and lead a very happy and rewarding life with your dog. The most amazing part is to watch as your confidence grows as the training progresses; from a person who has been stressed out their entire time they’ve had their dog, to stress-free. We can take your guilt or embarrassment your dog may be causing and turn that into pride and happiness. 

The Virgin New Adventures seventh Doctor novel Lungbarrow (written by former Doctor TV series writer Marc Platt) featured K9s Marks I and II meeting for the first time on Gallifrey during the events surrounding the disappearance of the Doctor's entire family house and his living relatives, which also featured many previous established Gallifreyan based characters. The two collaborated towards rescuing the Doctor, then current companion Chris Cwej and the Doctor's lost family. This novel also served as the direct lead-in story to the 1996 Doctor Who telemovie.
×