Today we are showing our appreciation for one of the Doctor’s most beloved companions, the all-knowing and adorable K9.

The robotic canine first appeared on our screens on Oct 1, 1977 in the Fourth Doctor adventure, The Invisible Enemy. Over the years K9 has left and returned, most memorable with Sarah Jane Smith in the 2006 episode, School Reunion, starring David Tennant as the Tenth Doctor and Billie Piper as Rose Tyler.

Here’s our handy guide to four decades with the tin dog!

One Previous Owner

As we discovered in the aforementioned story The Invisible Enemy (pictured below), K9 was actually built by Professor Marius in the year 5,000. Described by his maker as a “computer”, Marius had to return to Earth and gave K9 to the Fourth Doctor and Leela.

Thankfully, he was TARDIS-trained.

There’s more than one!

In even more shocking news, K9 is not unique. The original left with his mistress Leela at the end of the 1978 epic, The Invasion of Time.

But, being the sentimental sort, the Doctor couldn’t live without his little chum and so immediately had a Mark II ready to go!

This version accompanied the Doctor and Romana on a hunt for the Key To Time (pictured above being repaired in The Stones of Blood) and eventually left with, fittingly, Romana II as the denouement of the 1981 four-parter, Warriors’ Gate. Sadly, this time, there was to be no replacement.

Or was there…?

Not a master of all terrains

Though a well-informed and talented computer, K9 lacked a certain something when it came to alien (and sometimes human) worlds.

The marshes of Kroll (in The Power Of Kroll), Brighton beach (The Leisure Hive, pictured above) and even the streets of Paris (City of Death) all proved too much for K9, and had to sit out entire adventures with his master and mistress.

 

First Doctor Who Spin-Off!

1981’s K9 & Company left you in no doubt who was the star of the show. K9 returned or, rather, Mark III made his debut on the very first Doctor Who spin off, K9 & Company.

Sarah Jane Smith was sent him as a present from the Doctor and the two soon became firm friends. K9 Mark III would reappear briefly in 1983’s The Five Doctors and then again in…

He’s back, again!

… 2006’s School Reunion. K9 Mark III made the ultimate sacrifice and saved Deffry Vale School after it had been overrun with Krillitane.

But, yet again, everyone’s favourite Time Lord couldn’t resist creating a replacement. The Tenth Doctor left Sarah Jane with another K9, Mark IV if you will, to keep her company and protect the Earth.

The Sarah Jane Adventures

The following year, the spin-off series The Sarah Jane Adventures launched with K9 making an occasional appearance to help out on Bannerman Road and also returned to Doctor Who to save the day in dramatic style in the Series 4 finale, Journey’s End(pictured above).

And, let’s not forget, K9 was reunited with the Tenth Doctor in a 2009 story from The Sarah Jane Adventures. The Wedding of Sarah Jane Smith (pictured below) saw the Time Lord team up with Sarah Jane’s chums and come face to face with The Trickster.

Remember the time K9 was on The Weakest Link?

Back in 2007, the lovable robot was a contestant on a very special Doctor Who edition, The Weakest Link (a quiz show which appeared in the 2005 finale). K9 appeared alongside Wholumni such as David Tennant (The Tenth Doctor), Noel Clarke (Mickey Smith) and Captain Jack himself, John Barrowman.

Sadly, our little chum was voted off in first round by his “friends”…

All of K9’s adventures are available on DVD.