At one minute past midnight (2301 GMT), "Harry Potter and the Half-Blood Prince" — the sixth and penultimate volume in the magical series — went on sale in Britain and beyond, following a breathtaking countdown at Edinburgh Castle which was made to resemble the book's Hogwarts School of Witchcraft and Wizardry.

To mark the moment, author J.K. Rowling read from her long-awaited novel live on television from inside the castle, which was also beamed onto a giant screen for 2000 children and their families seated behind barriers outside.

Potter parties worldwide

Thousands of other "Potter parties" took place at the same moment in book shops in Europe, Asia and Africa as fans — young and old — scrambled to get their hands on the first copies.

Five hours later, more than 5000 outlets across the United States joined in the frenzy, opening their doors to the muggle hordes once the magic stroke of midnight sounded.

"Excited, I am excited," the blonde-haired Rowling told reporters in Edinburgh, just minutes before the launch. "There are a lot of answers in this book. I can't wait for everyone to read it."

Her fans could not wait either, with many pledging to devour the 607-page doorstopper over the weekend to find out whether a rumour that a key character is killed off is true.

"I have to go to my Saturday job, but shall read it during breaktime," said student Fiona Dixon (17) who queued outside an Edinburgh branch of Waterstone's bookstore from 8am.

Bookstores stay open to sell book

Waterstone's, like its counterparts worldwide, stayed open long into the night to sell the book in a special Potter paper bag to tens of thousands of customers and re-opened early on Saturday morning to continue feeding the ravenous fans.

"As the door opened, they swarmed into the shop," said Swagat Sengupta, manager of the Oxford Bookstore in Kolkata, India, where fans had been waiting since dawn. "Everyone was excited to have his copy first."

Britain's WH Smith chain of bookshops, which took a half-million pre-orders, said the book flew off the shelves overnight at a rate of 13 copies per second.

"We are still expecting this to be a record selling book," company spokesperson Sarah Hodson told AFP, noting that by late afternoon, shops had enjoyed a continuous stream of customers.

Rival book chain Ottakars, which changed its name to Pottakars for the occasion, said sales at a main branch in Edinburgh were definitely higher than for book five of the Potter series, and similar success was enjoyed at scores of other branches nationwide.

Half of books sold had 'grown-up' cover

Demonstrating its broad reach, store manager Matthew Perren said about 50 percent of the books sold were the adult version — the same content but with a more "grown-up" cover — with the children's version accounting for the other half of sales.

"It's been absolutely crazy," he added.

Others ordered over internet

More than a million other avid Potter readers, opted to receive their fix through the post after ordering the novel over the internet on Amazon.com and other websites.

"It is just a compulsive read. You can't put it down. I will probably be late for work tomorrow because I will be finishing the book tonight," said Keith Mcleish (17), a student from Edinburgh.

Global sensation

Such passion is what turned a simple children's story into a global sensation that is expected to sell some 10 million copies within the first 24 hours.

The series has also spawned three blockbuster movies and top-selling merchandise.

British publisher Bloomsbury was distributing Potter's latest adventures in Britain, Canada, Australia, New Zealand, Hong Kong, Singapore and South Africa while US publisher Scholastic was serving up a record 10.8 million copies to the American market.

"You ever been hooked on a soap opera? Well, imagine having to wait two years for the next episode," said Ileana Santamaria (25), who was first in a queue that snaked around a Barnes and Noble bookstore in downtown Manhattan and out into the street.

Similar scenes, some on a smaller scale, hit English-language bookstores in continental Europe as die-hard fans rushed to enjoy Potter's latest struggle against the evil Lord Voldemort even though it meant enduring their own struggle — reading the tale in English.

Noemie Cheral (12), waiting with her mother outside the Paris branch of British book chain WH Smith, said she "makes a big effort to read in English to be able to take part in discussions at school".

Translations of "Harry Potter and the Half-Blood Prince" are to hit foreign bookshops in the coming months.

AFP