10 Behind The Scenes Reasons For Doctor Who Characters' Quirks

K9 is a much-beloved additional element to the Doctor Who family. Lasting from The Invisible Enemy all the way up to Warriors' Gate, albeit changing models, the robotic canine remains one of the longest staying companions on the show. Despite being a fun, quirky addition to the TARDIS team K9 sadly came with a lot of baggage, and this ultimately developed his ongoing traits as an unreliable character.

It's not by accident that K9 was never featured within certain locations, meaning he missed out traveling the marshlands in The Power of Kroll, or wasn't invited to Paris in City of Death. This was down to the actual prop being unable to travel within these specific terrains, or would've simply been too much of a burden being used on certain locations.

Even the whole premise of a second model for K9 was indicative that the first model was scrapped in favour of a more responsive variation of the prop, one that was less noisy and didn't interfere with the camera equipment when it came to the remote control's radio signals.

Unfortunately, K9's malfunctioning nature became a prominent quirk during his final season when producer John Nathan-Turner decided to slowly pull the plug on K9, making him less present during the plots due to being left behind, blown up or simply dismantled.

Even Season 17 wasn't kind on the poor loyal canine computer when he missed out from battling the Daleks (after catching laryngitis on-screen to hide the fact that he wasn't suitable for extensive quarry shoots) and even had a voice change upon John Leeson stepping down from the role. Although Leeson would later return upon being told K9 was being written out of the show completely. Poor K9.