Why is Russell T Davies so good at his job? How is it that he can turn out one acclaimed hit after another, from Queer as Folk to Bob and Rose, a run of unprecedented success that has now reached a glorious prime-time frenzy with his revival of Doctor Who and its various spin-offs: Torchwood, shortly to transfer from BBC3 to BBC2, and his own favourite, The Sarah Jane Adventures, for CBBC?
I don't think this question is especially hard to answer. Davies is an incredibly talented writer, but he also loves television: I mean really loves it, and in the most unsnobbish way. He's a consumer as well as a producer. Ask what he watches himself, and he'll pause for a minute, like a child contemplating glass jars in a sweetshop.
"Oooh," he says. "Well, there's Corrie [Coronation Street]. Always Corrie. It's so brilliant. There's Bodies, and Gavin and Stacey, the most fantastic thing that's been on for years. And I love reality TV. I get pissed off when actors complain there's no drama on television. Big Brother is drama; it is crafted, it's a story well told." Where does he draw the line? Is there nothing that he won't watch? "Yes! Amanda Burton. I won't have that woman on my telly!"
This passionate enthusiasm is charming (and funny), but it also means that Davies lacks the hand-wringing tendencies of most of those who write about television, and many of those who work in it. Tapping his mobile phone frenetically against the table at the London club where we meet (he's desperate for a cigarette), he tells me that he doesn't believe in TV's so-called Golden Age.
"I'm sick of reading that it's all going to shit. The other day I saw Hollyoaks. They'd done anorexia. Yes, how boring is that? But the story was about two anorexics encouraging each other, and it was incredibly powerful. Now, Hollyoaks is on at 6.30pm, five days a week. The trouble is that [the naysayers] don't really watch telly. They don't watch normal output [like that]. You might as well ask an MP what he thinks of television."
He is amazed by the spectacle of BBC high-ups acting like - to quote Jeremy Paxman - an order of self-flagellating medieval monks, offering pre-emptive cringes to all and sundry. "Telly is so ashamed of itself. When a problem comes along, it bows and buckles and is fucked. It lets itself be, in a way that novelists or opera never would. They're apologetic because it's just in the corner of the room, burbling away. There aren't enough people taking enough pride in it."
Having begun his own career in children's television - he produced Why Don't You?, the show that told kids to switch off their TV sets and go and do something less boring instead, like, er, build their own hovercraft - perhaps it is understandable that, of all the "scandals" that rocked the BBC this summer, he is most infuriated by the one over the naming of the Blue Peter cat. "Don't even get me started on that shit. I was appalled.
That man [the programme's former editor, who was sacked] was utterly dedicated to Blue Peter. So, they changed the name of a cat in a poll. Who gives a fuck?" Of the researcher who plucked a child from the studio audience and got her to pose as a competition winner after the Blue Peter phone lines failed, a dishonesty for which the BBC was fined £50,000, he says: "That was clever, frankly. They're live on air, so she gets a kid in to fix it."
If this sounds provocative, it's meant to: it stems not from a belief that people should be allowed to do as they please when spending public money, but from an understanding of the intense pressures of 21st-century TV. "Interactivity, the red button, all that extra content with no more money in the budget. So, if something goes wrong, of course you're not giving it your full attention. You're just trying to get your programme on air." Is the BBC safe? Will the proposed job cuts be detrimental to its good health? "Oh, I don't think the end is in sight, although every empire falls in the end. It could be smaller, to be honest. Could you merge BBC2 and BBC4? I think you could, and you'd have a fine channel."
The irony is that he is enjoying the biggest success of his life in-house at the BBC, with Doctor Who. (The Christmas special, centrepiece of the Christmas Day schedule, will star the Titanic, Bernard Cribbins and Kylie Minogue, a surreal combination that only Davies, master of the impossible, could conjure up.) And, as a result, he is now one of the most influential people in British television (and number 15 in the Guardian's Media 100).
How long will he go on? He recently told a newspaper that he wouldn't like to do series seven - and season three is only just out of the way. "I miss Manchester. That's where my house is, and my boyfriend. I have to travel between there and Cardiff [where Doctor Who is made] and I've only just worked out my socks and knickers routine. Doctor Who is terrifying because it's so visible. We have eight million viewers. We can't get away with making a bad episode. But it's also the best job in the world. I control the mothership. I say: 'I want Pompeii, with rock monsters!' How great is that?"
Why, I wonder, did Doctor Who succeed when so many people (including me, a long-time fan) felt the attempt to resurrect it was obviously doomed? Davies is momentarily lost for words. "I don't know. People had been asking for 20 years: why does science fiction work in the cinema and not on television? So I thought: all we can do is be cinematic. It's a big show. I don't mean ratings. I mean big emotions, big pictures. It's never half-hearted."
Are there other series that he thinks are due a dusting down? Not really, though he admits to a touch of envy that someone else - Adrian Hodges, who wrote ITV's Primeval - is bringing Terry Nation's apocalyptic Seventies series Survivors back to our screens. But when he has done with Doctor Who, he will go back to writing his own stuff, use some of the ideas he has got carefully stored up.
"Oh, yes, I've got a plan," says Davies, with the air of one who, however modest, also knows that commissioning editors across the land hang on his every word.
Rachel Cooke’s pick of Christmas television
I realise that I'm in danger of losing what little credibility I have by saying this, but I cannot tell a lie: on Christmas Day, no matter how loudly my brother groans, I will be watching the return of Audrey Forbes-Hamilton (Penelope Keith) and Richard DeVere (Peter Bowles) in To the Manor Born (25 December, 9.30pm, BBC1). So will lots of people. We know that this one-off special will probably be silly. We know, too, that it is unlikely to be very funny. But, back in 1979 - yes, I admit it, when we were children - we loved this story of a bankrupt aristo (Keith) who must look on as a wholesale foods magnate (Bowles) buys her beloved home, Grantleigh Manor; we especially loved it when, after years of class-bound animosity, they fell in love and married. So, are we going to miss the chance to find out how they got on? No, we are not.
It's shrewd of the BBC to bring this one back: TTMB drew up to 23 million viewers an episode, so if even a small proportion of them return this December, it will have scored a ratings triumph. And ratings triumphs are still what Christmas telly is all about. In 2006, thanks to the incredible success of family shows such as Doctor Who, there was an upturn in BBC peak-time viewing on Christmas Day following years of decline due to competition from DVDs, video games and digital channels. In an effort to repeat this trend, its 2007 schedule has an even more comforting and old-fashioned feel.
TTMB and Doctor Who (25 December, 6.50pm, BBC1) aside, highlights include a new adaptation of Oliver Twist (starts 18 December, 8pm, BBC1), starring Tom Hardy as Bill Sikes, in half-hour episodes - a form that worked so brilliantly for Bleak House; Noel Streatfeild's blissful Ballet Shoes (26 December, 8.30pm, BBC1), for children and nostalgic adults; and a Strictly Come Dancing special (25 December, 8.30pm, BBC1) that will be bolstered by a BBC4 dance season which will include Dance Britannia (starts 27 December, 9pm), a history of popular dance, and the films (hurrah!) of Fred Astaire and Ginger Rogers.
I will also be watching the Arena special (24 December, 8pm, BBC2) about Ken Dodd, that most critically neglected of British comedians, and Dave Cameron's Incredible Journey (20 December, 7pm, BBC2), in which the Conservative leader receives the Michael Cockerell treatment.
Other channels are trying to pull a similar trick to the BBC's, a duvet-like warmth falling over every evening's viewing. On Sky 1, Noë Edmonds will revive his long-forgotten show Noë's Christmas Presents (23 December, 7pm), in which he doles out treats to the deserving - a saccharine-fest that is best avoided. But ITV's adaptation of Dickens's Old Curiosity Shop (26 December, 9pm, ITV1) must be worth a go: Toby Jones will play the villainous Quilp, and he is one of the most watchable actors we have.
If your Christmas is going really badly - if Granny is being even less tactful than usual - console yourself with Christmas at the Riviera (24 December, 9pm, ITV1), a comedy drama set in a dismal Eastbourne hotel on Christmas Eve. It's by the people who brought us The Worst Week of My Life, which means that, if nothing else, it will be powered by a sense of chaos that will make even your day seem smooth-running.
And if you have an edgier sensibility? Well, there's always Extras (27 December, 9pm, BBC1), which returns for a Christmas special - though I, for one, find Ricky Gervais increasingly hard to take. Or, on Channel 4, there is the delicious prospect of David Starkey crisply analysing the royal family in a Monarchy special (26 December, 8.30pm). Hippest of all, however, is BBC3's Liverpool Nativity (16 December, 8pm), in which Joseph and Mary are asylum-seekers and Herod is a Home Office minister. Music by the La's and the Zutons.