“I do have closure with Harry,” Rowling told reporters in London at the launch of www.pottermore.com. “I have no plans to write another novel. I'm pretty sure I'm done on the novel front … But it was fun while it lasted.”

“It is my view you can't hold back progress,” Rowling said of the electronic launch.

“Ebooks are here and here to stay. Later than a lot of people, I for the first time downloaded ebooks and it's miraculous for travel and for children in particular. I feel great about taking Harry into this new medium.”

"It's a great way to get back to the Harry Potter readership," she told reporters. "I had more than half of the new material already written."

'I wanted to give something back to the fans that have followed Harry so devotedly over the years, and to bring the stories to a new digital generation.

'I hope fans and those new to Harry will have as much fun helping to shape Pottermore as I have.

'To add to my input into the website, everyone will be able to join in by submitting their own comments, drawings and other content in a safe and friendly environment – Pottermore has been designed as a place to share the stories with your friends as you journey through the site.'

"We knew there was a big demand for ebooks, but...I wanted it to be something more than that," the author explained.

"I wanted to pull it back to the reading, to the literary and story experience...I've had a lot to do with virtually every aspect of it."