What was your first job?
From the age of seven or eight, my siblings and I worked during our holidays in one of our father’s stores because, as he put it, “You children need to know that money doesn’t grow on trees.” We were paid two and sixpence a day to greet customers, wrap parcels and shadow floor walkers. I would have preferred to clean sewers than work for Daddy because he was such a hard taskmaster. If he caught us leaning on a counter, he’d say, “Stand up straight and set a good example.”
You were born with a birth defect. How did you pay for corrective surgery?
I was born a girl, but with a cosmetic genital malformation, which led to me being registered as a boy. In 1949 the medical profession thought it preferable for a child to be given the “superior” sex – you were at least stacking the odds in its favour.
When I was 21, I decided to have corrective surgery in New York, but needed to find $5,000. My mother tried to stymie me, but mercifully my grandmother offered to foot the bill, as did my aunt. Mummy, who was very competitive, made a contribution when she realised it would look bad if she’d done nothing. Later, when everything was sorted out, she swiped a whole heap of the money and bought herself a diamond watch bracelet and her 15th engagement ring.
Have you ever worried about paying the bills?
Yes, because I refused to marry for money. My duty, as my father constantly pointed out, was to get suitably married. Men rather liked me and I was considered good looking. I could have married some wonderful guys, including a lord who has been in various Conservative governments, but I wasn’t in love with them.
When I gave up the American businessman David Koch to marry Lord Colin Campbell, the younger son of the 11th Duke of Argyll, my father thought I was nuts – and in some ways he was right. David died last year leaving $51bn. I was smitten by Colin, however. He had the strongest personality I’d ever encountered. He was also very persuasive – we married within five days of meeting.
Just before the wedding, he asked me to waive all rights to his trust fund if things didn’t work out, which I was delighted to do. He then tried cajoling me into selling my jewellery and asked my father to settle an annual income on him. When all that failed, he tried to sell a story to a tabloid newspaper revealing that I had been brought up as a boy. I decided to leave him after 10 months, and he and his brother put an even more negative spin on the story to make more money, claiming – falsely – that I had had a sex-change operation.
What did you earn from your divorce?
Despite having asked me to sign a prenuptial agreement, Colin discovered it did not protect his trust fund after all. He had overstepped the mark and got me to sign away all my rights to alimony, instead of just some. This meant the agreement wasn’t valid in New York, where his trust fund originated, and I was entitled to 50pc of everything he owned there. We settled on 15pc, but I would have been happy to take nothing. In return, he got all the contents of our New York apartment, bought with my money.
Was there an obvious turning point in your career?
Yes, my 1992 biography of Princess Diana was a worldwide bestseller. I benefit from my track record because, unlike many other royal biographers, my books have stood the test of time.