Harry Potter film is leaked online ahead of release

It's a mystery as unfathomable as any phenomenon at Hogwarts. How did the first 36 minutes of the new Harry Potter film leak on to the internet?

Executives at Warner Bros said they were investigating the leak of a section of Harry Potter and the Deathly Hallows: Part 1 on file-sharing sites ahead of the movie's release this Friday. The film was made available for download on sites such as BitTorrent, according to a report on file-sharing blog TorrentFreak. "This constitutes a serious breach of copyright violation, and theft of Warner Bros property," said a spokesperson for the company.

"We are vigorously investigating this matter and will prosecute those involved to the full extent of the law."

The Harry Potter films have so far made some £3.4bn in worldwide ticket sales. A second instalment of the latest film will be released in July next year.

Meanwhile it emerged yesterday that author JK Rowling told Daniel Radcliffe, the actor who plays Harry, that she plans not to write any more Harry Potter books, despite rumours to the contrary. Radcliffe said he had received a text from her that said "she felt I'd been very good in this Harry Potter film, and as a reward for that she wasn't going to make any more Harry Potter films".

He added: "I'm sure she will be writing other books, but I can pretty much guarantee Harry will not be a feature."