Not content with resurrecting the timelord, Russell T. Davies then went dipping into Doctor Who history to bring back the Doctor’s 1970s companion Elisabeth Sladen, who plays the title role in the Sarah Jane Adventures. It was, of course, a hit with children for whom Doctor Who is still too scary. No sofas required, then, for the start of its second series.

Is it just for small children?
The one thing I demanded is that the threat would always be real rather than comic, though we make it a lot lighter and with a lot less fear. On Doctor Who we consider the eight-year-olds or the 10-year-olds, but with this you seriously have to think of six-year-olds. It doesn’t sound like there is much difference between 6 and 8, but they are actually a vastly different creature. Part of you also has to remember that the six-year-olds watching the series last year are seven-year-olds now, and they are into it, they get the mythology and want to see things dealt with in detail. So the scripts for this second series are a little more complex.

How dark can it get?
Kids love dark. I think it’s only adults watching who worry about that. Harry Potter gets as dark as hell in some places. All the great fairytales and myths are full of loss and longing. You’re an idiot if you remember childhood as just laughing, running about and having a good time. But I think it’s a job of good children’s drama to include the full range of emotions, which also includes happiness.

Why bring back the Brigadier, another Doctor Who supporting character from the 1970s?
It works beautifully in Sarah Jane because it’s as if she goes to visit her grandfather – the wise old man who is the keeper of secrets and can help save the day. They don’t have long conversations about how they defeated the Daleks in 1972.

Would you introduce any more characters from the old series?
We’ve got to limit it. It’s not a pension plan for people who used to be in Doctor Who.

Would you ever feature the Doctor in SJA or would that be wrong?
I don’t think that would be wrong, not at all. It doesn’t happen in this series partly because you want the series to stand on its own two feet. We might consider it in the future, but it’s certainly not the first thing on our agenda.

Were there any misgivings about having a middle-aged woman front a children’s show?
No. I once tried to create a spin-off of Queer as Folk with Vince’s mother Hazel at the heart of it. At the time, Channel 4 was up in arms that a middle-aged woman would be at the centre of the action, so it never happened. They are idiots. It would have been magnificent.

Didn’t the BBC originally suggest the idea of “a young Doctor”?
They did, and I threw it out of the window. It would demystify the Doctor having a boy running around saying, “I am the Doctor” with a sonic screwdriver. Just rubbish.

Would you consider writing a show for teenagers?
God no. People keep making shows for teenagers, who aren’t watching television – but they never will. They are too busy snogging and being miserable in their rooms.

— The Sarah Jane Adventures, Mon, BBC One, 4.35pm

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