Hannah Stephenson talks to a former York student whose children's books are now nearly as big as Harry Potter.

YOU can tell when a children's author has made it big: film-makers start falling over themselves to rush their characters on to the big screen.

They don't come much bigger than Anthony Horowitz - one JK Rowling excepted, of course.

His teenage spy Alex Rider - a kind of orange juice-drinking junior James Bond - comes second only to Harry Potter in the bestseller stakes.

The six novels featuring the teenage MI6 agent have sold three million copies in the UK alone. And Alex has been credited with creating a whole new generation of boy readers.

No surprise, then, that the first Alex Rider book - Stormbreaker - has now been turned into a £30 million film, due for release this summer.

Horowitz, who studied English and art at the University of York before abandoning an advertising career to become a full-time author in his late 20s, has now turned his hand to horror. But despite the change of genre, there is no sign of the Horowitz magic fading. His new horror novels - part of a five-book series entitled Power Of Five - are already outselling Alex Rider in America.

Evil Start, the second book in the series, is a supernatural chiller in which young hero Matt Freeman goes on a frightening adventure to stop the forces of darkness destroying the world. Horowitz describes it as "Stephen King for kids".

"The inspiration for this series was the sense that something has just gone wrong with the world," he says. "I'm thinking about Iraq, Guantanamo Bay and things like that which are in the news all the time.

"Every day has a capacity to shock us with what we learn about things. It's almost as if behind the facade of our everyday life, there's something absolutely terrible happening or about to happen. The sense of doom, of mistrust, is pervading our lives. It's everywhere."

The Power Of Five books are quite scary and will spook some children, he admits. "But there's nothing wrong with that. Nightmares are fine if you wake up and you're in a comfortable bed and you've got parents and there's daylight."

Read to the end, he urges, because all his books have a happy ending.

"Matt Freeman has a lot of bad things happen to him - there's a lot of death, a lot of violence and fear, but the fact remains that at the end of the book he is stronger than when he began. He is not dead. No children die in my books."

There are adventures, spills and thrills aplenty, however.

That's what attracted him to children's writing, the author, who now lives in London, says.

"What has always got me going is story. I love adventure, escapes and chases. Children's books have a purity about them which allows me to do that.

"It's fun, adventure and peril. When I try to be more adult and serious, I come a cropper. I'm not so well-equipped to deal with adult emotions and sensibilities."

Evil Star, by Anthony Horowitz, is published by Walker Books, priced £6.99

Updated: 10:18 Saturday, April 29, 2006