I feel that if I'm writing a book, it has to be an honest book: it has to say what I believe to be the truth, so that's kind of warts and all.

For much of the final decade of the 20th century, one story regularly dominated the news across much of the developed world. It was the unravelling of the marriage between the heir to the British throne and his beautiful, charismatic princess, Diana.

William's marriage to Kate Middleton showed that social class, which seemed so important when Prince Charles was looking for a bride in the Eighties, is no longer an issue.

My house is full of paintings by my mother Pam. She was a fantastic, prolific artist but had no confidence in herself, thanks to my father running her down. They married during the war when she was 19 - she had planned to go to art school. But my father didn't want her to work, so she became a housewife.

Diana became a superstar when she became a part of the Royal Family because she brought youth and glamour and fun into a staid and dusty institution, and at times she eclipsed the Prince of Wales. It was one of the early problems within their marriage.