Even by Doctor Who’s variable standards, The Invisible Enemy commits a lot of sins. Its acting is even hammier and its effects even dodgier than usual. It’s got a standard runaround, shoot ‘em up plot, when it’s not moonlighting as a disaster movie or ripping off Fantastic Voyage. But for many, the greatest crime a Doctor Who story can have is a rubbish monster and The Invisible Enemy has a particularly egregious one, twice. It’s the Nucleus of the Swarm –  first a bin bag with a hairy eyeball and then a giant prawn which needs assistance to walk around. I mean, any monster which needs two attendants to help it trundle down a corridor is never going to convince as a serious threat. When it first appears, fronds waving in Tom Baker’s face, he’s trying to swat it away like the embarrassing irritation it is.

But this story’s place in Doctor Who is assured because it introduced K9. K9’s a controversial figure in Doctor Who, some loving him like a surrogate pet and others thinking him a childish indulgence. But one thing is undeniable. K9 is, by any measure, hopeless.

He moves at a top speed of “glacier” and even that causes his motors to whine loudly throughout. Good thing he never has to sneak up on anyone. His nose laser is strangely anaemic and its aim is variable. Sometimes it will strike someone in the knee but injure them in the stomach. His movement is erratic; at one stage he drives straight into a wall. And he can’t roll over the lip of the TARDIS doorframe, meaning he has to enter and exit the Ship via means of discrete cutaways.

What makes K9 worth persevering with is his voice, delivered by John Leeson. Think of all the different ways Leeson might have gone with this. Looking at the squared off metal terrier, he might well have adopted an excitable, yappy tone. Or perhaps delivered all his lines as a kind of halting bark. But instead, he went for the tone of a mildly exasperated mid-career accountant. Unexpectedly, this works beautifully and makes you want to hear from K9, hoping he’s going to contribute to a scene. And of course it allows some relationships to develop between him and the other characters.

K9’s function within the show veers from being exposition machine to mobile (or immobile, depending on the terrain) gun, but frequently he rises above this to demonstrate the wry charm of a sufferer of the Doctor’s silliness. Plus Leeson’s deadpan delivery allows K9 to occasionally deliver nicely self-referential gags. Like in The Pirate Planet (yes, I’m still going on about that one!), when he predicts the Doctor’s imminent arrival because he can sci-fi smell him coming, and when the Doctor finally booms in with a “Are you surprised to see me, K9?”, K9 dryly replies, “Amazed, Master” and steals the scene. Or in The Armageddon Factor when the Doctor idly says, “I think one of us is being extremely stupid” and K9 says quietly but knowingly, “Affirmative.”

So technically a nightmare, but narratively useful and, with Leeson behind the microphone, a charismatic addition to the TARDIS crew. The production team had every chance to get rid of K9, and given the challenges presented by the prop, they’d have been sensible to do so, but they brought him back for three seasons in a row, until John Nathan-Turner and Christopher H Bidmead thought he was altogether too convenient and sent him packing  (and even JN-T brought him back for a special, hoping a spin-off series could be cobbled together around him). The reason why, of course, was that the audience, and particularly kids, loved him.  In 1977, Doctor Who needed to be popular with kids.

K9 was an acknowledgement – the first for a very long time – that children are part of the Doctor Who audience. He’s a potent signal that the show is conscious of its younger audience; incoming producer Graham Williams had been instructed by his bosses to take them into consideration by lightening the tone of the show. If K9 seemed like an unnecessarily childish element to older viewers who had got used to the show’s mix of gruesomeness and black humour, then he did exactly what he was designed to do.

nardole

He’s also the first of a different breed of companion, which I like to call the “secondary companion”. In Season 15, Leela (Louise Jameson) is the primary companion and main foil for the Doctor; she’s in every episode and gets plenty of dialogue and action. K9, however, gets plugged in and out of stories as he’s needed. He isn’t in it all the time. If the terrain is too boggy this episode or you don’t want him to compete with the Daleks for attention or you don’t want to take him on holiday, you leave him in the TARDIS. No biggie. No wonder the Doctor refers to him as his second best friend. He utterly is.

It’s a companion configuration that the 21st century version of the show uses all the time. Jack and Rory are secondary companions and Mickey even self-identified as the tin dog.  They’re the Doctor’s second best friends. But the character where K9’s influence is most keenly seen is Nardole.

Like K9, Nardole acts as the Doctor’s confidante and aide-de-camp. Like K9, he does the boring technical stuff the Doctor doesn’t want to do and turns up occasionally to spout exposition. Like K9, he’s a fussy, uppity butler-type and he drops in and out of the series depending on whether he’s needed or not. I don’t mean to damn him with faint praise, but Nardole basically is K9, but better able to cope with hills and able to walk in and out of the TARDIS without assistance. And just as it’s difficult to imagine a spin-off series for Nardole, the various K9 solo vehicles, are, I fear, doomed to ignominy. His value is as an adjutant to the Doctor and as brilliant as he is at that, he’s not lead character material.

Back to The Invisible Enemy, and the story’s end where Professor Marius (Frederick Jaegar, of which university) appeals to the Doctor to let K9 travel aboard the TARDIS. Leela is delighted, but the Doctor says nothing. Tom Baker looks distinctly grumpy about the whole idea. He’s already got one scene stealing companion, in a skimpy outfit which makes it impossible for her to not steal focus from him. Now he’s got a robot dog as well!

For years after he’ll complain about the unreliability of the prop or the need for shots with him crouching down, but I’ve always thought that his antipathy towards K9 is mainly about competition for being adored by children. In that regard, he at last has a companion to give him a run for his money. Just not one that could actually run.

LINK TO The Leisure Hive and The Pirate Planet: Three stories in a row with Tom and K9! But we’re about to random it up again…

NEXT TIME… If you could touch the alien sand and hear the cries of strange birds and watch them wheel in another sky, would that satisfy you? It’s back to the very beginning for 100,000 BC.