BBC's festive Potter treat

The Harry Potter books are worldwide bestsellers

BBC Radio 4 became a Harry Potter zone for Boxing Day when the network transmitted an uninterrupted reading of the first book about the teenage wizard.

The eight-and-a-half hour marathon version of Harry Potter and The Philosopher's Stone was read by Stephen Fry.

It followed negotiations with Radio 4 controller Helen Boaden and Rowling's agent, Christopher Little, who insisted the book had to be read unabridged and in one go.

Helen Boaden: Wants younger listeners

The normal Radio 4 schedule, with news and features, remained on long wave while the FM schedule was cleared for the reading.

Fry's recording is already commercially available, but Radio 4 predicted listeners would keep the programme on all day and dip in and out.

Ms Boaden, who has been in her post for eight months, is keen to win over younger listeners to the station and is starting a dedicated children's spot next year.

She envisages a generation of current children who, when in their 20s, will look back and remember listening to the radio on Boxing Day.

Stephen Fry welcomed the news that his Potter reading would be broadcast in full.

"Reading Harry Potter books out loud is more fun than I feel a single human being could ever deserve. It's like swimming in chocolate," he said.

The reading started on Radio 4 FM at 1200 GMT.