Most famous for being one third of TV’s The League Of Gentlemen, Mark Gatiss plays a mad scientist in the latest adventure for Doctor Who, entitled The Lazarus Experiment. Here, he talks to about being the bad guy…

This isn’t the first episode of Doctor Who you’ve contributed to, is it? How did you first become involved with the all-new Doctor Who series?
“I knew Russell [T. Davies, writer] a little from some other things and we were both good, old-fashioned Doctor Who fans. All of us who loved the original show were always talking about trying to bring it back so, when it did come back, Russell rang me up and asked me to write for the series.”

How did your role in The Lazarus Experiment come about?
“I’d written two episodes for the new series [The Unquiet Dead and The Idiot’s Lantern] but I’ve always wanted to be in it as well. And this year, out of the blue, I got a call offering me this part. It’s a fantastic part; I’m a proper Doctor Who baddie. I play a mad scientist.”

Ah, yes, Professor Lazarus. Tell us about him?
“In the beginning, I’m 76 years’ old, then become younger and then I turn into a monster – it’s like three villains in one really! Professor Lazarus invents this machine called the Genetic Manipulation Device, which makes him young again, and he’s trying to sell the idea so he unveils his machine at a wine and canapés launch. And that’s where he meets the Doctor and Martha.”

Why does Professor Lazarus want to make himself young again?
“The professor has been scarred by his experience in the war; as a child being terrified of the bombings in London, and he’s using the machine to help him cheat death. The machine works but he’s obviously using a corrupt strain of technology, which the Doctor knows is not going to last. It affects the professor’s DNA and he starts to mutate into a horrendous computer-generated monster.”

So, is Professor Lazarus really evil? Or is everything just the machine’s fault?
“I think he’s misguided. His motives are very genuine – he really just wants to cheat death. He thinks it’s a crime that people have to give up when they’ve got so much more to offer. But the Doctor believes that everything has its time and that the important thing is to do what you can in the time you have, and not to horribly, artificially extend it.”

If Professor Lazarus is just misguided and not evil, as you say, surely anything bad that happens is just down to the monster he’s created?
“But once he becomes the monster he starts to think that it’s the new version of humanity, which is superior. Professor Lazarus must be monstrous deep down – otherwise he wouldn’t come out like that.”

Who’s this Mr Saxon chap?
“He’s Professor Lazarus’ paymaster – he’s the money behind it all. He’s a character running through some upcoming episodes, but I don’t know any more than that.”

Have you seen the finished episode?
“Yes, and I was thrilled with it. It’s funny because, one day, I went to the effects studio to do some dubbing but I didn’t want to watch chunks of the episode without having seen it all. But the guy in the studio just pressed play and then started talking on the phone, so I stopped him and said: ‘No, please turn the lights out and get out of the room’. I didn’t wait 35 years for my Doctor Who debut just so someone could talk through it.”

How did you cope with all the prosthetic make-up?
“It’s the most I’ve ever worn. It’s a full head and it took three hours to put on. But I loved it. It’s amazing what a difference it makes, it changes everything about you; the way you sit, the way you move and it slows you down.”

So you felt every bit like an old man then?
“Well, so that I could look really old, I got the producers to make me some cloudy lenses to ‘dull’ my eyes a bit. But then I couldn’t really see much, so I was hobbling around the set with my stick because I genuinely couldn’t see. But it all helps to get you into character. I was actually given one of my heads to keep, so I’m going to put that in the attic and see if it keeps me young.”

Being such a fan of Doctor Who, what do you think of David Tennant as the Doctor?
“He’s fantastic. Everyone loves him and kids just worship him – it’s an extraordinary thing to witness. The show is bigger than it ever was. It’s just a wonderful time to be doing Doctor Who and, hopefully, I’ll be writing an episode for next year.”

Finally, can we expect to see any more from The League Of Gentlemen?
“We’re hoping to do something; we’re just not quite sure what it will be yet. But we definitely want to, so stay tuned…”