Joss Whedon, creator, head writer and executive producer of Buffy the Vampire Slayer and Angel, walks into our interview at the end of a very long day. As well as juggling his two established hits - Buffy is in its seventh season, Angel its fourth - he has spent the best part of last year developing a new series, Firefly.

In the end, the US network Fox decided to shelve the series after a sluggish half year in the ratings and Whedon, despite his youth, shows all the scars of battle.

``I won’t do this again,’’ he concedes. ``I won’t do three shows at once. I’m only doing it this year because I got myself into this, like an idiot. I love these shows, and I won’t let them down, but I won’t do this again.’’

Meet a man with a very tall in-tray. The two stars in his stable - Buffy and Angel - have loyal audiences around the world and command the complete attention of the man who created them.

Unlike many producers who handball TV series to a show-runner and a staff of writers, Whedon steers both productions personally.

``The workload is every bit as big as you would imagine it is. It’s almost too much for a human being to stand, and it’s been the hardest year imaginable,’’ he says.

``I am better at it than I was the first year of Buffy, and I probably get more sleep than I did,’’ he laughs.

``But every single minute of every single day that I am not home is spent accomplishing something. There is no down-time. That’s how it is with two shows. With three it is much more intense, and I’m working harder on the shows than I was before.

``I complain a lot, and I feel that is justified,’’ he says, with the faintest hint of a wry smile. ``I’m overworked and overpaid.’’

"I won’t do this again...three shows at once. I’m only doing it this year because I got myself into this, like an idiot." - Josh Whedon

It’s been a tough year, not just because of Firefly’s premature demise. Buffy the Vampire Slayer is sliding towards its curtain call. US network UPN’s deal to broadcast the series expires in May, as does the show’s contract with its high-kicking leading lady, Sarah Michelle Gellar.

An announcement was made this week that the series will cease production in May and will end with a five-episode story arc and the return of some old favourites.

Gellar announced last week that she would be leaving when her contract expired.

Whedon is now considering other possibilities, including a spin-off series based around the character of Buffy’s sister Dawn (Michelle Trachtenberg) or her friend, the witch Willow (Alyson Hannigan).

At the time of our interview, though, having just given birth to a series - the futuristic Firefly - Whedon doesn’t look like a man anxious to go through the process again.

Like parenting, the process is exhausting, and requires a parent to balance the needs of the new child with those of his older children.

``They feed you, too, and you love them so much,’’ he says. ``It’s not like laying bricks. I get a huge amount back. Every time we break a story, every time I watch the footage or see a great performance, I get jazzed as hell, so it definitely gives you something back.

``A new show has to have that onset attention more than any other, but where it really happens - for any show - is in the story-breaking. Figuring out the story, figuring out what it means, figuring out all those beats.

``I’ve got competent people to write them. I know they can do the job - not every time, sometimes they airball, everybody does - but most times out of the gate they will get it right as long as the story is right. When we start, the big dry erase board is blank, every time.’’

When both shows end their seasons in the US in May, Whedon will have supervised 232 hours of his supernatural high school franchise. That’s a whole lot of fake blood, even for the man who banished Angel (David Boreanaz) to hell and killed Buffy Anne Summers (Gellar) in a grisly fifth-season finale. Needless to say, both lived to fight another day.

The experience, says Whedon, has been cathartic. And it has toughened him considerably.

``I am not nearly as nice as I was,’’ he laughs, reciting a parody of himself performed by his colleagues: `` `Men, we’re going to take that hill . . . Well, probably not, most of us will probably die, we probably won’t take the hill . . . We don’t need the hill to win the war, I don’t think morally we should win the war and, anyway, I’m afraid of hills . . . ’

``Even though I love (my) writers, if they’re not giving me what I need, I get all mean and scary. I won’t settle. I’ve settled occasionally and known it, and regretted it.

``I’m probably not as pleasant to be around as I used to be - but we’re getting it done.’’