EDINBURGH in August and in the upstairs bar of the Gilded Balloon Teviot, while a transvestite choir in full drag practise scales a few feet away, Lady Colin Campbell is telling me about the time her father suggested she should kill herself.

I think it’s clear that I’m a little shocked. Lady C, as everyone seems to call her around here, however, seems a little more understanding. “Look at it from his point of view. It was an extraordinary situation.”

Well, yes, I agree, raising your child as a boy when she’s actually a girl and then suggesting she kill herself when this becomes a problem does seem an extraordinary situation. It’s also an extraordinary thing to say.

But scandal was such a big issue for him, she explains. “His ideal solution for me was to commit suicide.”

To suggest that to your own flesh and blood, though.

“Yes, but how many people with problem children haven’t wished it?” she asks me. “The fact that he recommended it is only because we come from a very direct family.”

It’s possible that you know Lady Colin Campbell for swapping insults with Duncan Bannatyne on ITV’s I’m a Celebrity, Get Me out of Here (fair to say they didn’t get on). But having creepy-crawlies poured on her head while Ant and Dec look on is frankly the least interesting part of her story. Author, socialite, Princess Di biographer (she revealed Di’s bulimia and affair with James Hewitt before Andrew Morton ever got round to it), one-time model, ex-wife of the younger son of the Duke of Argyll (a marriage that might, to be kind, best be described as eventful), a woman who was finally the recipient of corrective surgery at the age of 21, having been born with ambiguous genitalia. Her life story is a Jackie Collins novel of a thing; sex and drugs and twinsets and pearls.

Lady C is wearing a pearl necklace this afternoon in fact. It shimmers dully around her neck as she chats. She’s in town to give people an insight into her gilded and at times grotesque life story via a Fringe show. The question is why? ”I’m whoring for Goring, darling,” she explains. “I’m whoring for Goring.”

This is her prepared soundbite which she’s been repeating to everyone since the news of her Fringe appearance emerged. Goring, in this case, is the 18th century castle in Sussex that was a derelict wreck when she bought it a few years back and still needs substantial renovation.

“The dome needs to be done, which is a vast expense alone.” If she makes any profit from the show that’s where it’s going. She’s hoping when the renovation is complete it will give her an old age pension as a conference, weddings and event venue.

When we talk it’s the day before her opening show and if there are nerves they are not on show. “I’m reasonably prepared,” she says. “Overconfidence has never been my problem. We’ll see. I’m reservedly optimistic.”

She is looking well on her 66 years (her birthday is later this month). Her face has retained the infrastructure of her younger beauty, her hair is blonde and thick, her accent a slow-release Jamaican drawl. As we sit talking her son Dima, one of two Russian boys she adopted more than 20 years ago, is nearby, eyes glued to his phone. He doesn’t raise his eyes even at the most outre moments of our conversation. He’s heard her story many times before, I guess.

It is, though, a remarkable one. Christened George William Ziadie, she was born in Jamaica in 1949, to a wealthy Lebanese Catholic family who were at the heart of white Jamaican society. After the war, she says, while Europe was in ruins, Jamaica was the premier winter colony. “Everybody came to Jamaica. Winston Churchill, Jack and Jackie Kennedy, Bill Paley, who was the head of CBS, the largest TV network in America at the time … Bill and Babe Paley had a house in Jamaica.”

And these people were mixing with your family? “Yes, obviously,” she says.

Her first memory is her second birthday party, one that was interrupted by the arrival of Hurricane Charlie. “A ship ended up on the street in Kingston. Not a boat. A ship.”

We could always run with the hurricane as a metaphor for her childhood and adolescence. “George” was born with fused labia and a deformed clitoris, and so the family decided to raise her as a boy.

If she’d been born five years later, she says, it might never have been a problem because of medical advances. “There’s a very famous movie star who will remain nameless because I don’t believe in outing anyone. She was born with a similar condition but she was brought up as a girl. The thinking changed in the medical profession.”

As a child her parent’s decision wasn’t a problem. Come puberty, however, the wrongness of her situation became increasingly obvious. She was bullied viciously as a result at the boy’s school she was sent to and by the age of 13 she began to “agitate” for her parents to address the problem. Instead, they sent her to a hospital under the auspices of a German couple who pumped her full of male hormones and were, she says, “truly monstrous”.

The woman, particularly, it seems. “I actually think she was a sadist. I thought she was enjoying the torment. I remember once when she was trying to inject me … And you can see,” she says, showing me the back of her hands, “I’ve always had great veins because I’ve always been very thin. When I went into hospital I weighed 84lbs, so I was pure veins and bones. I don’t remember how many times she poked to get the veins. And you could tell she wasn’t doing it because she missed the vein. She was making a point. She was horrible. Horrible.”

You might say the same of a father who put her in that place in the first place, of course. One who would also suggest suicide might be a solution.

“It’s easy to condemn but where does it get you?” she asks. “Although growing up I absolutely loathed him. But once it was sorted out I just left it behind.

“And to give him credit he tried to make amends and consistently did until he died. I know he lived to regret.”

And anyway, she says, he was a creature of his time. The family name mattered more back then than the individual. “Would the Duke of Buccleuch have done anything differently? Or the Duke of Argyll. Or the Marquess of Linlithgow? I don’t think so necessarily.”

She’s less forgiving of her mother. “She was a very mixed-up woman, very spoilt, utterly self-centred.”

It was only when her grandmother, her mother’s mother, realised what was going on (and who Lady C tells me in passing – and this may explain a thing or two – had never held a baby in her life. That’s what nurses were for, she believed) that things changed. It was her grandmother who said she would pay for corrective surgery in New York.

At which point her mother said she would contribute as well. “Mummy, of course, jumped on the bandwagon, knowing of course there was no need. She was trying to retrieve the situation; not where I was concerned, but her reputation within the family.”

She was 21 when she underwent surgery. Afterwards she remembers being flooded with a sense of release. “I would just burst into tears for no reason at all. Grand jags. And I realised that it was all the pent-up emotion. It was really just tremendous relief that I could actually start to have a life.

“Before that I was like a pauper at a banquet behind glass. I’m starving and everybody else is gorging themselves on fabulous food. Everybody had a fabulous life and I wasn’t allowed to have one at all.”

So when the door to the banquet opened what did it taste like?

She grins. “Oh, delicious. Delicious.”

She once said that her twenties and thirties were all about men. “It’s true. In my twenties and thirties it was men. In my forties and fifties it was my kids. And now it’s Castle Goring.”

Did the fact that suddenly all these men desired you bolster your sense of self? “Well, obviously. But then I came from a family of beautiful women. My mother was a professional beauty. She played the vamp for all it was worth.

“In fact, she was a warning to me of how not to use your looks. Because I could see how badly it ends. I made sure I was going to focus on character and accomplishment. I wanted to be a writer and I ended up being a writer.”

That said, Lady C’s looks weren’t a hindrance in her younger years. She’d been working as a model even before the surgery. And, as we’ve already established, her twenties were a whirl of partying and boyfriends.

She was going out with David Koch in 1974, one of the richest men in the world, when she met the man whose name she still uses, Lord Colin Campbell, younger son of the 11th Duke of Argyll. They got married five days later.

Why did she say yes when he proposed? “Oh, he was divinely attractive. And he was very decisive, very charming and exciting. He was lovely and fabulous. Like a shooting star.”

Plus, her father was putting pressure on her to marry. And it was her brother who told her to dump Koch, because “‘the only thing he can talk about is oil tankers,’” she says.

“In our world marriage was the best option for any woman. No girl ever chose to have a career unless she couldn’t get a man. It was very much a tertiary life.

“I said I wanted to marry for love and daddy actually said ‘love isn’t all it’s cooked up to be.’ Looking back I think he was actually speaking about himself because he loved mummy and he had a terrible time with her.”

Five days is surely not long enough to know whether you want to marry someone or not, is it? “Yes. I think [you can tell after] 30 seconds. It’s either there or it isn’t.”

What followed might question the wisdom of instant attraction though. She doesn’t really have much good to say about her ex-husband (who to be fair has on the few occasions he’s spoken about her been equally uncomplimentary).

At what point, I ask, did she realise the marriage was a mistake? “A few hours after he slipped the wedding ring on my finger. We were alone for the first time and he didn’t do what every other guy had done before and has done since. He didn’t try to leap on me. It went downhill from there.”

She says she had never before encountered a man who wasn’t a “sexual being”. She also alleged in her autobiography that he was drug-taker who could be violent. Lord Colin has dismissed all of these claims.

The marriage lasted 14 months. As a parting gift, she believes her husband sold the story to the papers - though he always denied this – claiming that his ex was once a man. Lord Colin also said that he hadn’t known that she had been raised a boy. Not so, says Lady C. “Everybody knew, my dear. You can’t hide things like that. It’s ludicrous.”

After the divorce she was in therapy for 20 years. But there were other men too. She had an affair with the actor Larry Lamb at one point. But in the 1990s she adopted two Russian boys and life took a different course. She hopes she managed to follow the good things her parents did – there were some, it seems – and not replicate the bad. “And I don’t think I did. My kids and I get on very well. I think they like me and I like them.”

Others do too. Since she appeared in I’m a Celebrity … she tells me she has been approached by so many people, especially young people, who have come up to her to say how much they respect and admire her, ”because I just am myself and evidently that seems to be a bit of a rarity nowadays.”

She says she’s never had one negative comment from members of the public, even though she spent much of her time on the show fighting with and bitching at fellow guests. She enjoys the recognition, she admits.

“I will not deny it’s a very pleasant and gratifying experience. But I have never lived my life with the thought of what other people thought of me.”

Does she enjoy being at the centre of attention? “I don’t like attention. I’ve had a great deal of attention all my life, rather more than I wanted. So I’m used to a degree of attention. But I spend an awful lot of time on my own. When you’re a writer you’ve got to have that academic bent and you’ve got to like being on your own.

“My idea of heaven is to retreat to my bedroom with a book with all my dogs and cats piled up around me.”

If that’s her idea of heaven I’m not sure what that makes performing at Edinburgh then. That said, she is clearly happy chatting about herself. As our conversation winds to a close I ask if things have changed for the better in the 21st century. I suppose I’m thinking she will tell me her take on gender rights and the like. She interprets the question as a historian, however. “Like all civilisations we’re on the arc of decadence,” she says. “We’re like, say, the beginning of imperial Rome. Of course Imperial Rome lasted another 1,400 years.”

What to make of her? Her ex-husband once called her a snob and she does tell me she believes that a degree of hierarchy is inevitable (“When you have an army of field marshals and no foot soldiers who is going to walk?”), but in person she’s likeable and funny and self-deprecating (to a degree).

And while it’s clear that Lady C may be many things – a name-dropper, someone who, whatever she says, likes to be noticed (and maybe that’s inevitable given that she grew up hiding who she really was)– she does not see herself as a victim.

“I have to tell you people who are born with handicaps don’t usually want to play the victim,” she says. “Because if you play the victim you can’t have a life.

“You cannot play the victim without disempowering yourself. You can’t wallow. As Heraclitus says, “character is destiny”. I think we in the western world now live in a world where everybody expects everything to be given to them. ‘Everybody’s entitled to happiness.’ I’m sorry. You’re entitled to what you are born with and the rest is what you make of it.

“You should have sympathy for others. Don’t have pity for yourself.”

A Cup of Tea with Lady C continues at the Gilded Balloon Teviot until August 28 (except for August 16).