When the young Mark Gatiss enrolled in the Bretton Hall drama school near Wakefield he was destined to meet the group of friends who would shape and design his professional life - Steve Pemberton, Reece Shearsmith and Jeremy Dyson, with whom he would form the League of Gentlemen.

But before that he had other things on his mind - skipping lectures and workshops to steal away to Bradford where he would ensconce himself in the Pictureville Cinema next door to what is now the National Media Museum and enjoy rare showings of old Doctor Who episodes.

This, of course, was well before Doctor Who is the household name it is now, under the highly successful reinvention at the hands of writer Russell T Davies and top-flight home-grown actors such as David Tennant, Christopher Eccleston before him, Billie Piper and Freema Agyeman.

But while Doctor Who was a couple of decades ago still purely a cult show for die-hard fans, those days also formed another future career path for the young Gatiss - as both a writer and actor in the shiny new 21st century Doctor Who show.

During the Christopher Eccleston incarnation of the travelling Time Lord, Gatiss wrote two episodes, the spooky Unquiet Dead, "starring" Charles Dickens, and the Idiot's Lantern.

And this year he appeared as the villainous Professor Lazarus in The Lazarus Experiment - a dream come true for the lifelong Doctor Who fan.

"It was a fantastic thrill," he agrees. "Both acting in the show and writing for it. When I heard Doctor Who was coming back I thought if they don't ask me to do something for it I'm going to kill myself!'.

"Fortunately, I didn't have to...to write two episodes was wonderful, but to actually appear in the show as well...it was a huge responsibility, really, because the show is so good. My secret worry was that I would be given a role as a comedy hunchback jailer or something, but Lazarus was such a great part."

Although predominantly known as an actor, thanks to his appearances in Doctor Who, dark sitcom Nighty Night, comedy-drama Funland and the current BBC Saturday night thriller Jekyll - as well, of course, as the often bizarre and grotesque the League of Gentlemen, which made his name - Gatiss, who was born in Sedgefield, County Durham, in 1966, sees himself mainly as a writer.

As well as writing for television and radio he is the author of two novels, the second of which has just been released in paperback.

The Devil in Amber is the sequel to his well-received debut The Vesuvius Club. Both novels feature Gatiss's creation Lucifer Box, the dandy socialite-cum-artist who lives at number 9 Downing Street (as Box himself says, someone has to).

He's also a secret agent for the Government, despatched to the far-flung corners of the globe to deal with Britannia's enemies. The first book had Box as a young gadabout in Edwardian London; The Devil in Amber moves on two decades to portray a slightly more middle aged - but equally rampant (with both sexes) Box.

The character is a delight, a cross of all the best bits of James Bond, Sherlock Holmes, Allan Quartermain, Flashman and Richard Hannay, all shot through with that darkly comic League of Gentlemen humour and Gatiss's immaculate ear for dialogue and eye for description.

Gatiss cheerfully admits to indulging some guilty pleasures for the research of his novels - throwing himself into reading the rip-roaring, Boy's Own-style adventures of a long-gone age, when men were men.

Gatiss seems to have tapped into a zeitgeist, with the success of the Dangerous Book for Boys, with its back-to-basics instructions for trapping small mammals and tying knots, and the resulting re-packaging by Penguin of a load of classics such as The 39 Steps and Conan Doyle's The Lost World in period covers complementing his own work.

"The Lucifer Box novels are the sort of thing I'd like to read myself," says Gatiss. "I've been absolutely delighted by the critical reaction to them."

He's already hard at work on the third novel, in which he is again going to fast-forward Lucifer Box another 20 years. At this rate there won't be many more adventures for Box...is Gatiss going to kill him off?

"Not at all," he says. "I don't believe in killing off characters like Lucifer. There are plenty of other adventures I can write... I've been thinking of doing a Victorian story, with a much younger Lucifer Box."

While he's working on the third Lucifer Box novel, though, there's the small matter of a stage appearance alongside British acting legend Dame Diana Rigg at the Old Vic in an adaptation of Spanish director Pedro Amodovar's movie All About My Mother, which runs from September 4.

After that...will there be more Doctor Who? Gatiss hopes so, and is convinced the revitalised show will go from strength to strength. "It was a huge gamble, I suppose, re-launching it, but it's been a huge success and what was formerly considered to be an extinct audience has been rediscovered. It's the show we used to love but with an added emotional depth. The question is, now what can we do with it?"

And what about the thing that started it all, the radio show that became a TV series that became a stage show that became a movie? What about the League of Gentlemen?

"The League of Gentlemen is dead!" announces Gatiss portentously. Then he laughs: "No, not at all. We've all been busy with other things, but at the moment we're just trying to co-ordinate our diaries and get together and decide where to take it next.

"The League of Gentlemen will return."

  • The Devil in Amber by Mark Gatiss is published in paperback by Pocket Books priced £7.99.