Doctor Who: Story Behind the Creation of K9

Doctor Who, the long-running British science fiction television series, has introduced countless memorable characters since its debut in 1963. One such character, the robotic dog K9, has captured the hearts of fans across generations. This comprehensive and engaging article delves into the fascinating story behind K9’s creation and its journey through the Doctor Who universe. Join us as we explore K9’s inception, development, and impact on the Doctor Who franchise.

K9’s Origins: A Canine Companion for the Doctor

The Birth of an Idea

The idea of K9 was born out of the desire to introduce a unique and futuristic companion for the Doctor. While Doctor Who had seen various human and humanoid companions, the creators wanted to push the boundaries of what a companion could be. K9 was conceived as a character that would add a new dimension to the show and appeal to a younger audience.

Designing the Robotic Dog

The task of designing K9 fell on the shoulders of visual effects designer Tony Harding and prop builder Dave Martin. Together, they created a robot dog that was both visually captivating and functional. K9’s distinctive appearance, complete with a boxy body, a computer panel on its back, and a retractable laser weapon in its snout, made it an instant hit with viewers.

K9’s Journey Through the Doctor Who Universe

Mark I: The First Adventure

K9 made its debut in the 1977 episode “The Invisible Enemy” as K9 Mark I, a creation of Professor Marius. The Doctor, portrayed by Tom Baker, encounters K9 during a battle against a swarm of hostile viruses. K9’s intelligence and abilities prove instrumental in defeating the viruses, and Professor Marius gifts K9 to the Doctor as a new companion.

Mark II: A More Advanced and Helpful Companion

K9 Mark I was replaced by the more advanced K9 Mark II, which accompanied the Doctor for about three years. K9 Mark II had improved perception and was able to warn the Doctor of impending dangers. It eventually suffered an injury and was left to retire on the Doctor’s home planet, Gallifrey, alongside Time Lady companion Romana.

Mark III and the Failed Spin-Offs

K9 Mark III first appeared in the 1981 spin-off attempt, “K-9 and Company,” which featured K9 and former Fourth Doctor companion Sarah Jane Smith. The spin-off did not receive a series order, and K9 Mark III’s journey continued in comics and audio plays. K9 Mark I also had a short-lived spin-off in 2009, which struggled with legal limitations regarding Doctor Who references.

Mark IV and the Successful Spin-Offs

The final iteration, K9 Mark IV, first appeared in 2006 during David Tennant’s tenure as the Doctor. K9 Mark IV joined the successful spin-off “The Sarah Jane Adventures,” making several appearances and solidifying its place in the Doctor Who universe.

Behind-the-Scenes Struggles with K9’s Rights

Creator Rights and Studio Conflicts

K9’s presence in Doctor Who was not without controversy. The creators of the 1977 episode, Bob Baker and Dave Martin, claimed rights to the character, leading to conflicts with the studio. This resulted in multiple attempts to create new versions of K9 to bypass the creators’ ownership claims.

The Resolution and K9’s Return

By the late 2000s, the creators and the studio reached an agreement, allowing K9 to make more consistent appearances in the Doctor Who universe. This resolution paved the way for K9’s inclusion in both the main series and spin-offs, solidifying its status as a beloved character in the franchise.

Lasting Impact on Doctor Who and Pop Culture

k9 dog robot Doctor Who

A Fan Favorite Across Generations

K9’s charm and unique design have made it a fan favorite for generations of Doctor Who viewers. The character’s appeal extends beyond the show’s primary audience, capturing the imaginations of children and adults alike. K9’s presence in the Doctor Who universe has also inspired other science fiction and pop culture creators to develop their own robotic companions.

The Legacy of K9 in Doctor Who

K9’s journey through the Doctor Who universe has left a lasting impact on the franchise. The character’s enduring popularity has prompted the show’s creators to occasionally revisit K9 in modern incarnations of the series, much to the delight of long-time fans. K9’s story serves as a testament to the creative genius of Doctor Who’s writers and the show’s ability to introduce unforgettable characters.


Who created K9 in Doctor Who?

K9 was created by Bob Baker and Dave Martin for the 1977 serial “The Invisible Enemy.” The character was designed by visual effects designer Tony Harding and built by effects assistant Nigel Brackley.

How many different versions of have there been?

There have been four primary iterations of K9 in Doctor Who and its spin-offs: K9 Mark I, K9 Mark II, K9 Mark III, and K9 Mark IV. Each version has its own unique features and storylines within the Doctor Who universe.

Why did K9 leave Doctor Who?

K9’s departure from Doctor Who was primarily due to rights issues between the creators, Bob Baker and Dave Martin, and the show’s production team. Additionally, practical challenges such as the robot’s limited mobility on set and changes in the show’s direction contributed to K9’s eventual exit from the main series.

Which Doctors have traveled with?

K9 has primarily been associated with the Fourth Doctor, portrayed by Tom Baker. However, the character has also made appearances alongside other Doctors, such as the Tenth Doctor, played by David Tennant, in various episodes and spin-offs.

Which companions have interacted with K9?

K9 has interacted with a variety of companions throughout its time in the Doctor Who universe, including Leela, Romana, Sarah Jane Smith, and others. K9 has also been a central character in spin-offs such as “K-9 and Company” and “The Sarah Jane Adventures.”

Will it return to Doctor Who in the future?

Although there are no concrete plans for K9’s return to Doctor Who at the moment, the character’s enduring popularity makes it possible that K9 could make appearances in future episodes or spin-offs. Doctor Who is known for its surprise character returns and nods to its rich history, so a K9 cameo or return is always a possibility.

How has K9 influenced other science fiction and pop culture?

K9’s popularity has had a lasting impact on science fiction and pop culture, inspiring the creation of other robotic companions in various forms of media. The character’s enduring appeal demonstrates the power of imaginative storytelling and the importance of memorable characters in capturing the hearts and minds of audiences.


The creation and journey of K9 in the Doctor Who universe is a fascinating tale that reflects the series’ enduring appeal and imaginative storytelling. From its inception as a unique companion for the Doctor to its various iterations and spin-off attempts, K9 has left a lasting impact on the franchise and its fans. As Doctor Who continues to evolve and captivate audiences around the world, K9 remains a beloved symbol of the show’s rich history and creative spirit.