Author JK Rowling has only half-finished the final Harry Potter book.

Fans have been warned they are in for a long wait before they get their hands on the last instalment of the boy wizard series, as Rowling dismissed reports she has already written 750 pages.

Writing on her website, she said: "I haven't written 750 pages of book seven and, if I had, I'd be very worried, as I'm not close to finishing it yet."

The Scottish writer also admitted she has no idea what to call the book.

She said: "I am currently trying to decide between two possible titles. I was quite happy with one of them until the other one struck me while I was taking a shower in New York.

"They would both be appropriate, so I think I'll have to wait until I'm
further into the book to decide which one works best."

Bloomsbury publishers were hoping the novel would be released next year.

The next Harry Potter film, Order Of The Phoenix, is due to be released this year.

Rowling, 41, recently revealed how she refused to be parted from the manuscript of her new book on a New York flight.

The mother of three explained: "A large part of it is handwritten and there was no copy of anything I had done while in the United States.

"They let me take it on, thankfully, bound up in elastic bands."