Harry Potter offers children a long spell at the cinema

Here's a problem to tax the most inventive of Hogwart spellmakers: what happens when you film the most popular book in history (after the Bible) and discover that it's too long for its target audience to sit through? Distributors throughout the nation have learnt that Harry Potter and the Philosopher's Stone, the most eagerly awaited film in years and a 24-carat guaranteed smash hit that will make Titanic seem like The Avengers, weighs in at two hours and 32 minutes.

It was passed by the British Board of Film Censors with a PG rating and without any cuts.

But will its length test the patience of the tinies in the multiplex? Children generally switch off their concentration button after an hour or so (15 minutes in the case of The Rugrats Movie). Two-and-a-half hours is long. It's nearly twice as long as Toy Story (80 minutes), an hour longer than The Lion King (89 minutes). It's like five episodes of Friends. It's damn close to eight episodes of The Simpsons.

Can today's children, their attention span as short as the presenters of Saturday morning television, remain awake for that long?

Will their parents fancy enduring 152 minutes of warlock whimsy, flying broomsticks and Maggie Smith doing her pinched-granny routine, with the smell of popcorn and spilt Tango in their nostrils?

There have been post-production rumours of Harry's unfeasible length for a while (four hours was once shudderingly hinted at) and speculation that heavy cuts would be needed to ensure the maximum number of cinema screenings. But the makers have insisted on 152 minutes, and nothing short of a personal intervention by the evil Voldemort will stop them. "There was a concern that people wouldn't want anything cut out," said Dan Jolin of Total Film magazine. "A hundred million people in the world have read these books and loved them, and there's a sense of the longer the better, even for children."

Anyone who watched their nine-year-old devouring the 600 pages of Harry Potter and the Goblet of Fire last summer will agree. But it doesn't make the prospect of Robbie Coltrane in a black fright wig any more appealing.