I don’t think I’ve ever worked on anything that was as difficult, terrifying and as much of a responsibility as writing the 50th anniversary episode of Doctor Who. I wanted everybody to love it. I knew that was impossible, but I wanted people – from those who had never seen it, to the absolute diehard fans who hate every episode I’ve written – to love it. So it was monstrously stressful and very hard: the uncastable cast, the impossible brief, the unwritable script…


I can remember sitting with my wife saying, “I can’t tell if it’s good any more, it could be rubbish – I’ll have to leave the country. I’ll have to fake my own death.” And then going for a meeting with the producers the week I was meant to hand the script in, and we were still trying to assemble the cast. We all just sat there, thinking, “This is impossible, this can’t ever work!”

All of these problems, of course, had been 50 years in the making. There was, I reasoned, only one story to tell if the Doctor was to meet himself – this had to be the day when he saved himself. And in the whole history of Doctor Who, there was only one day he needed saving from.

There was a tremendous crime committed during the Time War that the Christopher Eccleston, David Tennant and Matt Smith Doctors have all referred to, but we’ve never seen it played out or seen the consequences of it. When we got John Hurt, with that extraordinary voice, I knew we could make his Doctor face that day – the most terrible day of his life. We would finally witness that moment.

By the time we discover him, the John Hurt Doctor has been fighting the Time War for centuries. He doesn’t call himself the Doctor, and doesn’t behave like him, either – this is our hero as a dark and battle-hardened general. I think it’s nice for a hero to have a dark chapter, although it’s a chapter we will probably never see again because that somehow isn’t Doctor Who.

Of course the Doctor is always capable of darkness – he makes terrible decisions throughout the show – but this war involved the deadliest of decisions because the stakes were so much higher. The Doctor is a good man, always doing things for a good cause, but at this point he is no longer the happy-go-lucky wanderer; he’s a dark warrior. The Doctor has always been able to solve problems. Here he admits defeat, saying, “I’m going to have to descend to the level of my enemies in order to fix this.”

Once we’d decided on getting more than one Doctor involved we wanted David back. David’s Doctor was struggling to move on from the Time War, Matt Smith’s Doctor had sort of got over the Time War so, add a mysterious Doctor who’s about to commit the crime to which his two future selves have slightly different attitudes, and you have a very complicated, and exciting, scene to write!

The hardest challenge of all was having the Doctor meet himself. For a start, he knows everything he is going to say. If you met yourself you’d probably find yourself slightly dull. And the Doctor can never be boring because most of all he hates being bored. The Doctor is an explorer, a bit of an adrenaline junkie, desperately hungry for new experiences. The universe is so huge and inexhaustible that he can’t bear to sit still. There’s no part of him that thinks that he’s a hero, there to promote justice in the universe. He just stumbles into situations by accident and, because he’s a decent and kind man, always tries to help. But really, all he’s after is new experiences. If you could talk to him he would say, “So many stars, so many planets, so many things to be understood – how can anyone bear to sit down?” He would ban the whole idea of chairs from the universe.

The moment that revealed most about the Doctor during this episode was when John Hurt’s Doctor says to his future selves, “What made you so ashamed of being a grown-up?” They both look at him… it’s him! They don’t want to be like him, and have rejected every single thing he’s like. At which point a lot of things become clear. You suddenly see David and Matt as men trying to repress the memory of the brutal old warrior they once were, and puppying around the place in order to prove that they’re charming and lovely and more human than ever, almost as a denial that they’d ever done anything so dark.

But now all that is over. In Matt Smith’s final episode he spent a thousand years on a planet watching everybody else age to death, while he ages very slowly. The Doctor is being taught a lesson. He’s not a human being, however much he larks around pretending he is. He is different and it’s time to stop play-acting. He goes back to being the trickier version of the Doctor, the fiercer alien wanderer. He’s not apologising, he’s not flirting with you – that’s over. That’s what the Doctor was like after the Time War but he’s not like that any more. He’s gone back and he’s changed it. Now he can go back to being a bit more Time Lordy.

Enter Peter Capaldi. There is something about Peter’s demeanour, his eyes, his attitude – he’s tremendously bright and that comes out on screen. When you choose a Doctor, you want somebody who is utterly compelling, attractive in a very odd way. None of the Doctors are conventionally attractive, but they’re all arresting. Handsome men don’t quite suit. Matt Smith’s a young, good-looking bloke from one angle but is actually the strangest looking man from another. You need that oddity; you need somebody who is carved out of solid star, really. Doctor Who is a whopping great star vehicle, despite the fact it changes star every so often. And so it really is built around the abilities, the charm, the magnetism of a succession of different actors. I’ve cast Matt Smith, Peter Capaldi and John Hurt, but the truth is, they all cast themselves – the easiest thing to spot in the world is sheer brilliance.

I always thought Matt, while a very young man, had something of the demeanour of a much older man, whereas Peter is a man in his 50s but is terribly boyish and young at times. I like the Doctors to have mixed messages about what age they are – you can’t really pin them down. The Doctors are all the same Doctor really, at the end of the day, but you can slide the faders up and down. And to emphasise the senior consultant over the medical student for once reminds people that he’s actually a terrifying old beast. Typically, Matt’s method would do that, too: occasionally just turn cold and you’d think, “You’re not really a puppy are you?” Just like Peter Capaldi’s Doctor will sometimes remind me he’s a big kid at heart.

Doctor Who: The Day of the Doctor is nominated for the Bafta Radio Times Audience Award. Tune into BBC1 at 8:00pm on Sunday to find out who wins.


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