Suspicions were raised after betting agencies saw a flood of betting on the character of Professor Dumbledore dying in the sixth instalment of the series. Most of the bets came from the town of Bungay, where the book is being printed, the newspaper reported.

Secrecy surrounds the plotlines of what has become the world's most popular children's book series and while writer JK Rowling mentioned that one of the characters may die in the book, she has never revealed the character's identity.

Blue Square, an online betting agency who had been offering odds on who exactly will die in the next instalment, became suspicious when they received enormous numbers of bets on the death of Albus Dumbledore, the 150-year-old headmaster of Hogwarts School of Witchcraft and Wizardry.

"We have taken nearly £6 000 worth of bets on Dumbledore in the past seven days," Ed Pownall of Blue Square told The Sun newspaper, "all have been placed in Bungay or nearby Beccles. A lot of punters have opened new accounts and placed a maximum bet of £50 each on what is an obscure market."

The printers in Bungay have printed all five previous titles in the Harry Potter series, but this is not the first leak to hit the printing works. A forklift truck driver employed at the firm admitted to stealing pages from 'Harry Potter and the Order of the Phoenix' with the intention of selling it to the media, The Guardian reported.

'Harry Potter and The Half-Blood Prince' will be released worldwide on July 16