By Paul Regan BBC News Online in London

Paul Burrell's book went on sale in stores on Monday

As staff at Waterstones' Piccadilly store in London stacked a modest display of the new title, pages were being thumbed in equal numbers by supporters and critics of the book.

"I would like to read it to find out Paul Burrell's side of the story," student Gohee Jeong said.

"I want to know if everything I read in the media is right."

But her friend, Sooyeon Jung, was quick to disagree: "Paul Burrell should have more respect for Royal privacy.

"The only person who really knows everything is the princess, but she can't tell her story."

Steady demand

These polarised views were typical of customers who visited the London store throughout the morning.

Fellow shopper Jim Connelly was in favour of the book: "Why not spill the beans?

Was Burrell right to publish? Friends Gohee and Sooyeon couldn't agree

"Paul Burrell was badly treated last year and he deserves some compensation."

Despite his views, Mr Connelly was one of a number of people who left without buying a copy of the book.

Tourist Michael Russell also refused to part with �17.99 of his money, saying: "The man was employed in confidence, he shouldn't betray that."

But while there was hardly a stampede at any of the stores in central London, a steady flow of customers kept the tills ringing.

Is Burrell right to publish? Profile: Paul Burrell Watch Burrell's interview here point by point

WHSmith predicts that A Royal Duty could easily make it into the top five biographies of 2003 - the company says the book is out-selling Hillary Clinton's 'Living History' by around four to one.

"Within an hour of our first delivery, we'd sold a third of our stock," said Jo Marino, PR manager for Waterstones.

Other stores across the country also reported strong sales, while Chester, Paul Burrell's home town, sold out completely by lunchtime.

WHSmith's business unit director for books, Gary Kibble said: "We are expecting Paul Burrell's book to be the biggest of the week across all genres."

The book includes extracts of private letters written to and from Diana, as well as claims about her marriage, break-up, subsequent relationships and death.