When he set up Michael O'Mara Books in 1985, his first project was a tie-in with ITN celebrating the Queen Mother's 85th birthday The book was an instant best-seller. But there was a time when he was the Palace's favourite publisher. In a curious way the whole mythology of monarchy has broken down and people do want the truth."The idea that O'Mara has set a new standard in books about the Royals might astonish the Queen. The Sun was commended recently for the accuracy of its royal stories. "The days when a tabloid editor would say to his royal reporter `I want a royal splash for Monday and I don't care if it's true' are gone.

O'Mara thinks readers are no longer satisfied by books based on what "a Palace source says" or "I understand from a close friend".The book also had a profound effect on the way the tabloid press reported the Royals "It totally altered the landscape," says Andrew Morton. "Royal biographies have to be more like political biographies when you are trying to give an honest picture of someone's political career."I get approached by dozens of people who have the inside story on something or other. But generally speaking they are of the Madame Vasso type and I don't think it's proper to publish that kind of material."The Diana book radically changed the style and content of royal bestsellers. "I think I've tried to set a new standard in royal publishing," he says. He was the man behind Andrew Morton's Diana: Her True Story which in 1992 blew the whistle on Charles and Diana's marriage, hastening the announcement that they were to separate.The book was the stuff of publishers' dreams. In its first year, 4.5 million copies were sold world-wide, with translations in 23 languages.

In O'Mara's office in Clapham, south London, the shelves are lined with different editions. Morton and O'Mara made millions from it.O'Mara, 52, says the secret of his success has been to do royal biographies seriously, with rigorous research and no idle speculation or tittle-tattle. I sat there thinking, `Blimey! Where are we here?' " O'Mara is an old hand at ruffling the Royals. And of the High Court judge who originally put a temporary injunction on the book, he recalls: "He was speaking in hushed tones, saying he was very worried what the Queen might think of all this. Born in the US, he has lived in Britain for 25 years, but says he cannot get used to British deference to royalty. "Fergie is just a dim girl who happened to marry someone in the Royal Family," he says.

He is the publisher who last week forced the Duchess of York into a humiliating climbdown in her legal battle to get a permanent injunction against Dr Allan Starkie's book, Fergie: Her Secret Life. "I Certainly couldn't be called a monarchist. That would raise some really loud guffaws," admits Michael O'Mara. Martin McGartland believes his brother, who can now barely walk unaided, was attacked because of his family name.. Nevertheless, the case threatens to deeply undermine the Special Branch informant network.Mr McGartland is threatening publicly to vilify the RUC by holding a press conference to accuse them of betrayal.In his statement he says: "It seems to me extraordinary that the British government should be treating a former agent in this way, someone who risked his life for a number of years working for British intelligence."Mr McGartland claims he still suffers regular nightmares with flashbacks of the moment when he threw himself through the window.In court, he will produce medical reports showing that he suffers from depression and anxiety attacks, as well as his mainly superficial physical injuries.Earlier this year, Mr McGartland's younger brother, Joseph, was kidnapped by the IRA in west Belfast and severely beaten. After initial resistance, the RUC acquiesced and has assigned him a team of police bodyguards.Mr McGartland has raised his fears with Harry Barnes, the Labour MP, who has passed details of the case and its likely repercussions to Sir Patrick Mayhew, the Northern Ireland secretary.