Remembering Doctor Who's John Leeson: K9 star reveals his Tom Baker and David Tennant stories - and talks the show's future

After actor John Leeson's passing, we look back at one of his final interviews.

Doctor Who's K9 and actor John Leeson

BBC/AUK

Published: Thursday, 12 November 2026 at 9:56 am

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This interview was conducted in August 2025, before John Leeson's passing in November 2026. This is the first time it has been published in full.

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When he made his first appearance alongside Tom Baker's Fourth Doctor, Doctor Who's most unlikely companion, robot dog K9, was originally intended to be a one-off character from writers Bob Baker and Dave Martin.

However, his popularity with viewers led to him becoming a permanent member of the TARDIS crew.

Designed by Tony Harding and operated by Mat Irvine, K9’s unique voice was provided by actor John Leeson and he continued to bring the character to life until his death on November 1 at the age of 83, including in fan favourite 2006 episode School Reunion and spin-off The Sarah Jane Adventures as well as numerous Big Finish audio adventures.

Leeson as K9 was the perfect foil for Baker’s Time Lord; their friendship and respect for each other endured for decades.

In one of his final interviews, Leeson spoke about his pride in playing the character for almost 50 years, K9’s infamous on-set malfunctions, whether Tom ever felt upstaged by his robot companion and his work away from Doctor Who…

RT: Doctor Who has been a huge part of your life, hasn't it?

JL: I've had a very busy life, really. As an actor, my career has sort of been divided into two. Half of my career has been pretty much as a stage actor and the television half of my career arose pretty much by accident. The phone went one day and it was my agent saying, 'John, I've just heard from the BBC, and they want to know if you'd be interested in playing not just one but two parts on BBC television?'

So I, of course, I screamed, 'Yes, yes, yes!' And the guy at the other end said, 'Well, no, no, no, no. Hold on a bit. Hold on a bit. They are only voice parts, and besides which, they're only going to be used in one programme.' So I thought, 'Well, it’s worth doing at least.' My chap at the other end said, 'There's nothing else going on, so you might as well take them up.' And that was from 1977 onwards.

But the most extraordinary thing is that I was told under no circumstances would there be anything after the first episode was shot and is in the can. So don't expect too much. And here I am in 2025 still attached to Doctor Who.

RT: It's incredible, isn't it? Almost 50 years on and K9 is as popular as he ever was… And a lot of it has got to do with these fantastic audio adventures that you do, isn’t it?

JL: Yes, it's quite incredible. I must tell you, the very first time that I went to America as the character K9 for a convention. Of course I took advantage of the fact that nobody over there knew what John Leeson looked like. So I was able to mingle with all the people who were going to the convention, and I spoke to the showrunner, and I said, 'Now, look, I'm missing a trick here. Why don't you tell the assembled company that I've missed the plane and in fact I am still coming, but I shall be late. And so while you're waiting for me, you folks, why don't you have a K9 sound alike contest? And what I'll do is join in the contest. Nobody knows who I am anyway, and you make sure that I don't win the contest.'

And so this is what he did. He said, 'I've just heard that John Leeson has actually landed at the airport and is on his way here. So we'll pass time by having this contest.' And so he let me into this competition. And lo and behold, when it came to John Leeson nearly arriving, he said, 'Right, everybody, get yourselves in order, because we'll run hands overhead and see which was the best K9 sound alike.' And the little guy [me], who just arrived, got in line, and of course, he didn't actually win, and the discovery was made, I think everybody was in no doubt as to who was the real K9. That was the first trick I was able to play.

RT: Any more memories you can share?

JL: There was another rather nice one but this was back at home. I can't remember the story title in particular, except it was a lovely day, and Tom Baker was involved. He was outdoors, and the director said, 'Okay, everybody, we're going to take five on this one, because we're clear on that scene. So Tom, you sit over there on the grass in the sunshine, and other people, you know, just to sit and wait till we're ready to shoot the next scene.'

I myself was actually in one of the BBC technical vans. I could be heard from inside, from outside the van. And Tom, of course, could have a conversation with me from where he was. He was outside the van, but he said, 'John, can you hear me?' And I said, 'Yes, I can, or Affirmative, or something like that.' Tom said, 'John, have you got your Guardian cross word with you?' So I said, 'Affirmative, yes, yes, I have. Tell you what. What do you think about number 16 across? Do you think it could be elephant?' So we had a sort of conversation about the crossword clues, which was fine. Now, what I didn't know, and what I couldn't have seen from where I was, was that those who had come to watch for the filming could hear and see. And that was Tom sitting outside this van and K9 plonked down beside him and both of them doing The Guardian crossword together, which was rather lovely, I think.

The other very special thing I remember was we did a storyline called The Stones of Blood. And Stones of Blood had a very distinguished actor in it; Beatrix Lehmann.

Beatrix Lehmann was lovely. She was very, very elderly, but she and I got along ever so well. And she said she came in to rehearsals one morning with what looked like a green grocer's brown paper bag. And she said, 'John, dear, I want you to have this.' So I said, 'Oh, what's this then, Beatrix?' So she said, 'Well, it's been very special to me. Very special. It was given to me years ago by a very distinguished friend, Ralph Richardson and I've no further use for it, so I'd like you to have it please. Please do accept it.' So I thought, 'Is it something for my lunch? What is she offering me?'

So I looked to see what it was, and it was a 1930s Leica camera. I don't know how much it must have cost in its day, but a real museum piece. And I said, 'I can't possibly accept this Beatrix.' So she said, 'No, no, go. Go on, because I don't need it anymore.' And so I did accept it, and I still have it. It's a very, very precious gift from my Doctor Who days and only two or three weeks after she had given it to me, and at the end of the storyline, Stones of Blood, Beatrix herself passed away, so I wasn't able to thank her properly. It was absolutely a wonderful gift.

Tom Baker wearing a large hat and oversized striped scarf looking ahead.

Tom Baker as Doctor Who. Anwar Hussein/Getty Images

RT: What a wonderful gift to be passed on. Do you have a lot of props and mementos from your days shooting Doctor Who? Have you got many K9 models?

JL: I have quite a quite a lot of K9 models in my possession. But what use I have for them? I don't really know, they are just there as sort of little memories of odd storylines I might have taken part on.

RT: When you were filming with Tom Baker was it difficult to operate K9? Was that a frustration for Tom and the cast?

JL: Well, it was not for me to actually operate K9. Mat Irvine was responsible for the operation, the physical operation of K9. I was simply there to provide the voice, and apparently K9 himself was pretty, sort of a power of his own when it came to moving around. I thought to myself, 'Well, obviously, K9 is pretty difficult to deal with. So he may not last very long in the series,' because studio time is very expensive, you know. So I thought to myself, 'My days as K9 will be numbered,' anyway.

RT: Obviously they had to deal with the challenges of Daleks that couldn't go up and down stairs. So I guess having another robot prop that was unpredictable was just another challenge?

JL: It was so unpredictable. I think it was on the same sort of electrical circuit level as the main lighting of the studio. So whenever K9 appeared on camera, he went all over the shop!

RT: Would the electrics be affected as well? Would the lights go on and off?

JL: They did go on and off. Yes, they did. I know that there were many headaches.

RT: Regardless of the headaches, the proof was in the popularity of the character. There would have been a time when K9's popularity was on the same level or even bigger than the Doctor, right?

JL: I was very lucky that the character went down so well with its audience, I really was.

Q: Did Tom ever feel he was playing second fiddle to K9?

JL: I don't know, you would have to ask Tom, of course. But I don't think Tom particularly liked the character of K9. I suppose, for feeling upstaged or something. But that's a matter you'd have to put to Tom, of course.

[In a recent interview with RT, Baker said of reuniting with Leeson for the Sir Sherlock audio dramas: "Ah, K9! How wonderful to be reunited with John Leeson. He’s always such an encouraging actor and shamelessly boosting my ego. He just is so easy to work with. Very supportive. A lot of silent 'thumbs-up' to each other. I guess because we've known each other for such a long time now, it just has its own chemistry. I mean, I know he’s been doing a bit of moonlighting by working with other Doctors but come on, David Tennant won't love him like I do!"]

RT: Of course, K9 made that glorious comeback in 2006 with David Tennant when the show returned. That must have been an incredible moment for yourself, and also, what an amazing moment to see a new generation of Doctor Who fans embrace K9…

JL: That's right, absolutely, a completely new audience and friends all over the world, really, for K9. It was very, very special. Very special.

RT: What are your memories of working with David Tennant on that?

JL: A completely different Doctor Who, indeed. But obviously, again, somebody whose brain turned on a sixpence, if you know what I mean, which was marvellous. So I was lucky on both fronts. Tom was always my special favourite. I have very soft spot for Tom. But why he should have a soft spot for me I don’t know!

RT: Of course that brilliant episode, School Reunion with the wonderful Elisabeth Sladen, and then that led to The Sarah Jane Adventures and even more K9 on screen…

JL: The Sarah Jane Adventures, those were wonderful. Fantastic. They really were. And she was lovely, absolutely lovely. A great loss to the business.

Elisabeth Sladen as Sarah Jane Smith with K9 in Doctor Who

Elisabeth Sladen as Sarah Jane Smith with K9 in Doctor Who. BBC/Adrian Rogers

RT: I agree. As you've said to start in the '70s and continue into the 2000s, you'd have to consider K9 as one of the great science fiction robots, up there with C3P0 and R2-D2, wouldn't you?

JL: Well, thank you for confirming it!

RT: Of course, it begs the question, why are we not having K9 back in Doctor Who? It would be fantastic to see K9 return…

JL: Well, I think the question of rust comes up a little bit. You’ll have to write a letter in your best handwriting to Russell and see what result that gets.

RT: Do you still watch the TV series?

JL: I haven't seen it for far too long. I know it’s sort of gone through so many different changes in its time. I have read that it seems to be safe, the programme idea as a whole. They're not going to be dropping Doctor Who. It's run a very, very long course.

RT: We had the barren years when it was taken off air, sadly. It’s sort of inconceivable to think of it not being on TV again, isn't it?

JL: It is, it is. It's very much a part of the of the fabric of British television.

RT: I would totally agree with you. You’ve said you haven't watched the recent ones. What do you think they should do to keep the interest alive or attract new viewers? Do you think it's a case of just having what I would call the classic monster of the week type stories?

JL: No, it needs clever ideas, really, somewhere to take viewers that they haven't been before, and some means of exciting viewers intellectually, as well as just simply by way of entertainment.

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RT: But in its essence do you think viewers like the new monster or the new villain for the Doctor to battle with? Is that the secret of your era?

JL: To an extent, I suppose so, yes. There was a commonality between the next storyline coming up. You knew somehow what you might be expecting, whether it was delivered or not was a matter of your judgment as much as anything else. But yes, something fairly solid to watch.

RT: What do you think of the casting of the Doctor over the past few eras?

JL: Don't forget, of course, that fashions change. Audiences change, expectations that audiences have change too. So you don't want to put what is standard fare in front of an audience, because that leads simply to boredom at the end of the day. It invigorates. It does and it must. That’s quite right. Anything like that is a benefit, I think, which is good.

RT: There was a rumour a couple of years ago of a K9 film. What happened with that?

JL: No idea. Nobody knocked on my front door!

RT: Of course you also played Bungle in Rainbow…

JL: Well, I did so much more than actually is up in front of people. The number of plays I did in the West End is enormous. In fact, I'm the only actor I know who actually got married three times on his own wedding day! Because I had to leave my own wedding reception early in order to get to the theatre in time to play the matinee. It was a comedy of some kind. I was in Dad's Army. I was in all sorts of things. So I've had a pretty good moulding for a background as an actor.

RT: Do you have great memories of Dad's Army and working with Perry and Croft and that wonderful cast?

JL: Dad's Army was wonderful to work on. That’s because all the actors weren't actors. I mean, well, because they were actors, but they all felt so real. They all felt as if they really were soldiers and sailors. They were a real crew. I only had a tiny part in Sons of the Sea, which was the storyline I was involved in, but at least I had the key line of the show. It was a very good episode. The cast are all welded together and supported by each other, which is lovely. You get such confidence out of that sort of way of working as well, which is very, very good.

Doctor Who is available to stream on BBC iPlayer. Dive into our Doctor Who story guide: reviews of every episode since 1963, plus cast & crew listings, production trivia, and exclusive material from the Radio Times archive.

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Authors

Philip Hamilton

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