Will it be an earthquake, like Andrew Morton's explosive 1992 account of the marriage of Diana and Charles? Or will it be as damp a squib as a score of other royal exposes published since? Only one thing is certain. When the long-awaited account of Britain's Royal Family by Kitty Kelley, queen of the warts-and-all showbiz biographers, is published on 23 September, you'll have to cross the Atlantic to find out, writes Colin Blackstock

Her dissection of the House of Windsor, entitled The Royals, is being published in the US and 11 other countries but not in the UK. She says it would fall foul of Britain's libel laws; her publishers claim they cannot find a publisher bold enough to take it on. What's all the fuss about?

Ms Kelley has spent four years compiling the investigation and hints that no punches are pulled, although she is under a strict embargo not to comment on the contents until publication.

"It doesn't have the kind of deference British writers bring to the subject," she says, "and for that reason it is not going to be published in the UK. The laws are so strong that you really can't write the kind of book that I have written, which is a straight-on look at the Royal Family."

Media speculation suggests she questions the fidelity of the Duke of Edinburgh while, according to the New York Post, she alleges the Queen Mother may have been illegitimate. Naturally, the publisher, Warner Books, is doing nothing to dampen the hype: advance copies are being held back, and American bookstores will be deluged with a million copies on publication day.

Ms Kelley is known for her close to the wire accounts of the secret lives of public figures. Her last book in 1991 was a scathing portrait of Nancy Reagan, suggesting adultery (with Frank Sinatra), unchecked power in the White House and untruthfulness about her background. Other books have targeted Jackie Onassis, Sinatra and Elizabeth Taylor.

Her efficiency in dissecting her subjects is matched only by the gore she leaves on the operating room floor. A New York Times reviewer once said: "She's an entertaining hatchet person whose mutilation techniques could put Jack the Ripper to shame, but as a historian and cultural critic, she's about as savvy as Geraldo Rivera [the TV chat show host]."

But Ms Kelley says she has talked to 1,000 people about the book and her reputation for keeping taped interviews is legendary.She says Buckingham Palace co-operated with her initially, but the Palace denies having anything to do with the book.

Ultimately, says Ms Kelley, the Windsors are a screwed-up family who are needed by the British emotionally, and she says the book will make people more comfortable about their own domestic problems. "Our dysfunctions are going to look like mere eccentricities. Theirs are played out on a huge scale."