Three of JK Rowling's schoolboy wizard books have been published and last week they held the top three spots in the New York Times bestselling fiction list, an unprecedented achievement. Thier success means Potter films are set to be as much of a screen phenomenon as a publishing one.

 

Warner Brothers will shoot Rowling's first book, Harry Potterand the Philosopher's  Stone, next year and will then film the two other stories. Rowling, who uses her initials rather than her name Joanne, is due to write four more books, on which there are also movie options.

 

For the first time auditions will be held in primary and secondary schools rather than stage schools. The government has given its backing to the proposal - intended to offer every child the opportunity of an audition - as part of its effort to attract more film-makers to Britain. School governing bodies will, however, have the final say on participation.

 

Moer than 4,000 children have already sent unsolicited applications for the part of Harry to Rowling and to Bloomsbury, her publisher. David Heyman, of Heyman Films, the film's producer, is looking for a boy  "aged about 10 to 12".

 

"The idea is that this youngster could act in the other films as both he and Harry get older.  We will scour the country for the right person. We have decided not to advertise but to use talent in schools, not just for Harry but the other children's roles, too" he said.

 

Chris Smith, the culture secretary, and Janet Anderson, the films minister, aim to increase the number of  American- financed films made in Britain. Despite lobbying, Steven Spielberg's Saving Private Ryan was filmed mainly in Ireland and the next Star Wars movie is to be shot in Australia.

 

The government also wants to support the Potter films because officials said the three books - the other two are Harry Potter and the Chamber of Secrets and Harry Potter and the Prisoner of Azkaban - are "clearly encouraging boys to read". Although Warner and Steve Kloves, the screen writer, are American , Harry will remain a British child with an English accent. "Joanne also insists that should be the case," said Christopher Little, her agent. Spielberg, who directed children in ET, Close Encounters of the Third Kind and Hook, is the frontrunner to be the director.

 

Rowling, 33, a former teacher, had the idea for Harry Potter - an orphaned child who discovers he is a wizard - on a train journey in 1991. Durring the next few years she made notes, often while sitting in a cafe near her Edinburgh home with her baby asleep in the buggy, and stored them in boxes. Her first attempts to sell the book were unsuccessful.  She was rejected by Penguin, Collins, and Orion among the leading publishers. Eventually she persuaded Little to represent her. He managed to secure a £2,500 advance from an initially sceptical Bloomsbury.

 

Rowling, says Little, is now "well and truly a millionairess". Although she received a comparatively small advance for her first book, she has always been on a  royalties deal. She is believed to have made around £3m - £4m so far and is expected by her agent to secure "£20 to £30m" over the next 10 years.

 

The books, which have been translated into 28 languages, have been a huge publishing success. Rowling has sold 5.5m copies in America  and 2.5m in Britain.

 

American publishers have complained that the books should not be included in the adult bestsellers lists because they are intended for children.. "The Harry Potter books are knocking Stephen King off the number one spot," said an American publisher last week, "and people don't like it" Although 90% of the books sold are read by children, at least 10% are bought by adults.

 

The boy who plays Harry can expect to become one of the best-known child stars. Some, such as Mark Lester, who starred in the musical Oliver!, have complained that the experience robs them of thier childhood. Lester is now an osteopath and acupuncturist.

 

By contrast David Bradley, a child star in Kes in 1969, has no regrets about appearing in Kan Loach's film.  "It opened doors for me," he said. "I suppose I did miss out on a normal adolescence, but it's okay as long as you get the right degree of parental guidance. If I were 11 I'd jump at the chance of appearing in the Potter film."