"I spoke to my dad about it and he said: 'That's never going to happen, Tamara.' " The billionaire was right. Ground down by the recession, viewers didn't find Ecclestone's million-pound bathtub amusing - nor did they see the intended "irony" in her declaring a pimple "a medical emergency" and racing to a dermatologist to have it zapped. "Living your life publicly opens you up to a whole load of criticism and I understand that, but I had hoped people would see another side to me. I don't really want people to take me seriously. I don't take myself that seriously."
Marie Antoinette-isms aside, it's hard to dislike Ecclestone. Untouched by real life, she exudes wealth - her skin is the colour of expensive fudge and her hair and lashes impossibly lustrous - but her eyes aren't money-deadened and there's none of the hardness of the super rich there. She's warm and giggly and feels misunderstood by her countrymen. Still, after toying with the idea of joining Petra in LA (where her sister splashed out £91 million on the late Aaron Spelling's mansion last year), Ecclestone decided that she couldn't bear to leave London and bought herself a 24,000ft "dream home" - still being refurbished - opposite Kensington Palace. "There has never been any competition between me and Petra," she insists when I ask whether there was any truth to rumours that the sisters fell out over the intended move. "We're very different but she's the person I trust the most in the world." She has Petra's initial tattooed on the inside of her wrist, and says she can't wait to be an aunt - even via Skype. "But in the end I do feel that London's home. When we get into the new house I hope never to move again. I've got a huge dressing room and I've built Omar [her boyfriend of two years] a 'man cave' so that he can have his poker nights there." And the famous bathtub? "I've not bathed it in yet, but I can't wait," she laughs. "Maybe I'll bathe in cow's milk in my crystal bathtub."
It was Ecclestone's mother, Slavica - a former Armani model from Croatia who divorced her husband in 2009 after 23 years of marriage - who encouraged her daughter to start up the charity initiative she's promoting today: an eBay shop of her discarded clothing, with all the proceeds going to Great Ormond Street Hospital. "I'm a hoarder," she says, biting her bottom lip. "My mother tells me I have problems, which I probably do. So we came up with the idea of auctioning off three items every 10 days to the highest bidder." She has 100 pairs of jeans, she tells me. "Jeans for when I'm fat and thin and when I'm just slobbing around. I buy wild printed jeans just to be different and never wear them." She's not so extravagant with shoes, she says. "I must have 150 pairs, and I know that's a lot, but these days I think we all have a really warped idea of what's a lot and what's not."
Even on the off-the-scale Ecclestone chart, the socialite has to concede that her sister Petra's wedding at the medieval Castello Orsini-Odescalchi outside Rome last year was lavish. "I loved my maid of honour dress. Petra's gown was by Vera Wang and even though I'm worried about copying her, I'd like mine to be too. I'm thinking of getting married in Gstaad, where we spend every Christmas," she runs on, "but then it would be snowing and I'd be freezing…"
The "Crack Baby", Boujis-inspired cocktails of vodka and champagne and mini cheeseburgers she has planned for the reception aren't just part of an idle fantasy: Ecclestone has found the man she wants to marry once she turns 30 - stockbroker Omar Kyhami. Only one thing could spoil the day, she says, and that's any friction between her parents. "They both came to Petra's wedding and they were perfectly civil to each other, so hopefully they'll do the same at mine."
Ecclestone's decision not to attend her father's wedding to his Brazilian girlfriend, Fabiana Flosi, recently made headlines. Has she changed her mind?
"No," she says tightly. "I'm not going. I like my step mum but I don't even know when the wedding is and, actually, I haven't even been invited." Ask whether that's what caused offence, and she gives an indulgent smile. "Well, I don't know that Dad knows when his wedding is - or maybe he doesn't want to offend me. Plus he knows that I'm very loyal to Mum. In a way I think he's trying to spare my feelings." Would it be so disloyal to go? "I don't know."
For the first time since we sat down together Ecclestone looks downcast. "I'm happy that Dad's happy but this just seems so, well, final. For the longest time I thought that my parents would get back together." What was it that went wrong? "My father was such a workaholic and Mum kept expecting that to change. Then when he got older and still wasn't slowing down,
constantly playing second fiddle to him must have got tiring. The thing is that my dad's first love has always been Formula 1, and I get that, because if you create a brand it must be really hard to hand it over to someone else."
Ecclestone wasn't so sanguine three years ago, when the split was on every front page. "My parents' divorce was the worst thing I've ever been through," she says, stroking Duke's head distractedly. "It was such a bad time for me." She took refuge in food, binge-eating her way through those painful months. "It was the biggest I've ever been. I always eat through stress and my God - I just ate everything. I would drink a bottle of wine every night then order Domino's pizza, McDonald's, chocolate fudge cakes from Marks & Spencer… it was obscene. I would never dream of eating that way now because it certainly didn't make me feel good." A paparazzi picture of herself at a party, several sizes bigger than the size eight she is now, broke her out of it. "I didn't even recognise myself. Still, I was lucky enough to have people around me that I could rely on. I started going to the gym and everything began to change." Now, she only wishes her mother would meet someone too. "Mum's so happy and loving her single life but I'd love her to meet a man." A toy boy? "Yes!" she giggles. "She still young and she's so hot, but she doesn't seem to be interested. She's still obsessed with being a mum."
Those who envy and resent Ecclestone for her wealth should consider that she was only 17 when her first boyfriend sold a "kiss and tell" to a tabloid - and that in February of next year, she will be forced to give evidence in a trial against the two men accused of blackmailing her for £200,000 in order not to reveal details of another past relationship. Those kind of sordid details make her "sweet-shop" life a little less covetable. "I've had people say to me, 'You're just lucky sperm,' " she winces, "but I've chosen not to let those things bother me any more. My dad's worked hard to give his children the best life he could. Of course we realise how fortunate we are, hence all my work with Great Ormond Street, which is the most rewarding thing that I do. Still it does become tiring, constantly defending yourself purely because you have a successful father. Would other people in my position give all their money away? I don't think so." She points languidly to the Birkin bag sculpture. "That was just to take the ---- out of myself some more. This is not a dress rehearsal - you only live once, so I'm going to do what makes me happy."
