Heather Mills bites back: her plan for world domination

'Beatrice questions everybody who eats animals. When we were in the South of France, there was a buffet for kids, and by the end of the week no one would sit near us because she would go over and say, "Why are you eating that cow's bottom?" or "Oh, look at that little shrimp with little eyes..."

Heather fancies herself a plain talker, no airs, definitely no graces. There's a sign in her loo that says: 'If any items apart from toilet paper get dropped in here, the bog monster will reach out and grab your dick or punani!' 'You need to be real,' she says, enlarging on why she has never had trouble attracting men. 'Down-to-earth, not fussy, not pretentious. I'll carry boxes, I'll clean toilets. I peeled 260 potatoes the other Sunday. That's why my nails are gone.'

It could also have something to do with the fact that her manicurist, Kerry Newman, went tabloid kamikaze, selling her personal 'revelations' (Heather's still in love with Paul, apparently, and forces her housekeeper to coordinate her bras). Another lackey bites the dust. They often do. Currently, a former nanny, Sara Trumble, is suing for sex discrimination (allegedly Mills made her get up at 7.30am to baste her with fake tan). 'She was a lovely person to start with, but she was with me five years and I spoilt her rotten and her head went into the clouds with all the travel and she sold her soul.'

Talking to Heather is making me dizzy. Almost sleepy. It might be the intensity of her pale-eyed stare, reminiscent of that hypnotic snake in The Jungle Book. It might be the lilting insistence of the Geordie voice: 'Vegetables are vegan. Fruit is vegan. Rice is vegan...' It wears you down, so when she gets more controversial - the US government suppressing negative findings about the dairy industry - you just nod and smile.

So you can guess who won the battle over whether Beatrice should be educated privately or, like Paul McCartney's other daughters, at a state school. At their other home in Kent, Beatrice keeps a pony. It's a far cry from Heather's own childhood in Washington, Tyne and Wear, where she had to care for her younger siblings after her mother left her allegedly abusive father. By ten she was 'an old hand' at pinching food from supermarkets, as she wrote in her autobiography Out on a Limb. 'I would love to have had the life and the love Beatrice has. That's why I'm over the top with her.'

'I love you! I love you!' Mills tells Beatrice when she drops in on our photoshoot with her Australian nanny. She is an only child and it looks set to stay that way. 'Never say never, but the world is so full of people that I think I'm lucky to have had one.' Mills insists that Beatrice isn't spoilt. 'I go to my friends in Newcastle and they have so many more toys than her, she's... oh, in wonderland. She's much more about outdoors play. Not toy overloaded.' But is it true she had a rather special fireworks display at her fourth birthday, featuring a £10,000 exploding hot air balloon...? The shutters come down. 'I can't talk any more about my daughter.'

It's often alleged that Mills is extravagant, but I see no obvious materialism. 'I could be shopping and going out for lunch,' she says, but instead she's investing in meatless meats, acquiring the vegan Redwood Wholefood Company, subsidising the café ('The prices are ridiculously low, but I want people to try vegan food'), a cruelty-free shoe company Beyond Skin, an eco-couture enterprise (restyling charity shop clothes) and algaebased omega-3 capsules to save the fish. You wonder how long the £20 million will last. A reference to the actress Natalie Portman's vegan shoe line Te Casan, now discontinued, elicits: 'But she had plenty of money to carry on, a lot more than I would ever have.

'I've just put everything I have into making this [the meatless café] work because, you know, life's short... It could have a huge impact but only if I make it into a worldwide franchise and roll it out across America.'

Mills ponders the story of her life. 'Why didn't I lose my leg when I was doing humanitarian work in Yugoslavia? I had to come back here to get my leg chopped off and get media attention. Why did my mother have to lose her leg, too?' Her mother actually lost a leg? (This is one of the issues on which Heather and the rest of the world, including her mother's then husband, the actor Charles Stapley, disagree. He maintains that her leg was crushed in a car crash but that she made a good recovery.)

'Well, they reattached it. It was hanging off by the skin. We didn't have much time together, because she left when I was nine, but it's weird how genetically you're the same. She did a lot of public speaking, and she was into homeopathy; she was quite innovative, so people thought she was nuts. She brought homeopathy to the Royal Marsden cancer hospital. She died aged 47. That's six years from now I'll be her age.' Heather looks into her rice milk latte with a soulful, prophetic expression that has a hint of 'You'll be sorry when I'm gone'.

Does she still feel her own security is at risk? Last year on that infamous GMTV interview, when she complained she'd had 'worse press than a paedophile or a murderer', she said that the police had told her she'd had death threats from 'a Liverpool underground movement'. She says no, she doesn't feel at risk any more, because the death threats were 'a set-up, to try and make sure that someone could get custody of my daughter, because she wasn't safe with me'. She makes this extraordinary allegation quickly, flashing her bitterness like a knife.

'God, that's so dark,' I say. 'Yup. So it was nice because I found out the whole thing wasn't happening. But it was a horrific thing to try and do.' And does she still have security? 'Yeah, full-time.' I haven't seen any sign of them. Are they around now? 'Always, yeah.' She looks behind her, semi-smiling at her invisible minders.

Then comes my favourite moment. I ask if Beatrice is musical. 'Well, yeah, because all her family are - I play saxophone and oboe, my brother plays bass trombone and has a rock band, my sister plays the flute, my mother played piano and my dad played six instruments, so...' I look at her sideways, trying to get her to laugh. Not a smile. But then, almost as an afterthought: 'And then her dad's musical, so, yes, she's totally musical.' Beatrice must think that, of her parents, it's Mummy who is the real achiever.

When we head down to her VBites café, it's buzzing. There are toddlers with soya bolognese all over their faces, old folk peering suspiciously at the pink thing inside their 'BLT', and stargazers who want Heather to sign their bill. There are six types of milk (soya, rice, almond, hazelnut, oat, quinoa) and holier-than-thou cupcakes (no gluten, no sugar) whirring round on a Yo! Sushi-style conveyor belt. 'Nice,' I say, and she replies, 'Thanks.' She saw them in Japan 15 years ago and thought they would work over here.

In Heather's world, she has to be the heroine of every story. Still, I really hope her café and her meatless meats succeed. She's infuriating and charismatic; visionary and egotistical all at once. It's like the good fairy and the bad were playing top trumps over her cradle. But both of them forgot to bestow one thing: a sense of irony. She looks out over the grey, windy Hove Lagoon, a hangout for pre-teen hoodies but otherwise deserted, even in mid-July, and says, 'I'm gonna turn this into an ice rink. It'll be just like Central Park.'

Make-up by Natalie Dean. Fashion assistant: Matilda Goad