The Goddess speaks out

Having a private lunch with Nigella Lawson is rather like trying to conduct a secret affair on stage at the Old Vic. As she sways to the table at Gordon Ramsay's new Boxwood Café, necks crane unapologetically. Ramsay pops out from his kitchen to bestow effusive kisses. And an entire battalion of waiters floats vaguely around our table like midges over a pond, darting in every few moments to reassure themselves that, yes, our water glasses are still full and our cutlery perfectly in order.

The second I go to the loo, one of them - a tall, Jamie Theakston lookalike - pounces. When I return to the table, Nigella, who's 43, is as pink as a schoolgirl. 'You wouldn't believe what he's just been saying to me,' she giggles. 'This is the proudest moment of my life,' declares 'Jamie', flourishing the autograph of his object of adoration.

Nigella's first book, How to Eat, was published five years ago and immediately won her a circle of foodie admirers. But it wasn't until she appeared on television that a star was born. With her hair loose and her feet bare, licking her fingers and smacking her lips over the deliciousness of her recipes, she made cooking sexy, incidentally inspiring a generation of impressionist comedians who make a good living imitating her breathy style. 'It's just the way I cook,' she protests. 'I thought I was being normal.'

Now, she has four bestsellers under her belt - not to mention an understated brand of duck-egg blue and taupe kitchenware - and, of course, a multimillionaire celebrity boyfriend, the ad man turned art collector Charles Saatchi. It's this relationship that has caused some of her fans to wonder if the Domestic Goddess has feet of clay. She was dating Saatchi publicly just six months after the death of her husband, journalist John Diamond, from cancer, and there were persistent rumours that their relationship predated Diamond's death and Saatchi's divorce.

'I know what's true and what isn't,' says Nigella, her chocolate-brown eyes suddenly stern. 'I do mind what people say, but you have to know what you're about, and then it doesn't matter.' Still, she can't have appreciated the decision of the ex-Mrs Saatchi, Kay Hartenstein, to pose suggestively for a magazine in a Domestic Goddess-mocking French maid's outfit and to accuse Nigella via 'friends' of flirting with Saatchi in front of a dying Diamond. 'She knows that's not the case,' says Nigella, who admits she found Kay's comments 'surprising'.

'I'm not mad on what she's said, but on the other hand, unhappy marriages make for trouble generally. What she said wasn't really about me. I did feel awkward about John's parents, but I feel they know what the truth is and that makes it slightly more tolerable.'

Last year, Nigella moved with her two children, Cosima, nine, and Bruno, seven, into Saatchi's Eaton Square apartment. 'We're existing in a disgusting, loved-up environment,' she says gleefully. 'It's very nice. We hang around, we watch DVDs.' It's hard to imagine Saatchi, who has a reputation for being a mysterious, chilly character, snuggling up in bed, scoffing cheese bagels, but Nigella describes him as cosy and 'frightfully normal', or as normal as you can be with an estimated fortune of £40 million.

The relationship has catapulted her into a new, extremely glamorous social sphere: in April she played hostess, clad in Vivienne Westwood, to 600 people at the opening of Saatchi's gallery at County Hall. Saatchi himself refused to attend. 'He doesn't like parties, he hates socialising and he'd have had a horrible time,' she explains. 'It would have been much harder to do with him hanging around saying, "Can we go home now?'''

Lesser women than Nigella might have been tempted to sit back on the cushion of the Saatchi millions. But she has other plans. She's just back from a publicity tour of the States, where her TV series, Forever Summer, has been airing on a cable channel. Her first TV appearance in the States drew mixed reviews, with some critics carping at her finger-licking style, calling it unhygienic. But she's successfully being positioned as the antidote to Martha Stewart, America's resident, impossibly perfectionist domestic goddess whose image has taken a battering over a stock-market scandal.

Her cookery book, Nigella Bites, was a bestseller there at Christmas, and she's just been pronounced Britain's sexiest woman by the chatshow host Jay Leno (in marked contrast to the ribbing he dished out to Jamie Oliver).

Right now, it seems her only problem is working out which tempting American offers to take up. 'I've told them, "Either I work and make programmes from England, or I go to America for five or six weeks and film there." But I just don't know if their appetite is such that I won't be able to work hard enough for them,' she worries.

In the flesh, Nigella is indeed beautiful, but hers is a grave, grown-up kind of beauty, not the Jayne Mansfield-style sex appeal she oozes on television. Today, her skin is pale, her hair, washed but not blow-dried, hangs limply and her famous pout is devoid of lipstick. 'I put some on this morning for our interview, and wiped it all off again,' she says. 'I can't really do lipstick; it makes me look like a dolly.' She's wearing her uniform of long Amanda Wakeley skirt, cinched about her waist, and Jitrois jacket that flares over her ample bosom. 'I find it so difficult to get clothes that fit,' she says. It isn't surprising: her waist looks like a size 6, while her hips must be a 14.

She scans the menu and unapologetically orders baby eels on toast, braised beef with mash and a knickerbocker glory with extra doughnuts on the side. The eyes of our fellow diners widen in surprise, but Nigella doesn't care. These days, she's given up on diets: 'They are about starving yourself. A lot of my girlfriends don't seem to like eating real food and just want ice cream and chocolate because they've lost connection with what's normal. I think the key to it all is portion control.'

Her fame and her reputation for oozing sex appeal from every pore seem to puzzle rather than faze her, but she remains level-headed, refusing to read what's written about her, whether good or bad. 'One of the great advantages of having a well-known parent,' she explains, 'is that you learn not to take fame too seriously. Once these things start to matter to you, you've had it.'

Nigella is, of course, the daughter of the ex-Chancellor of the Exchequer Nigel Lawson and his first wife Vanessa Salmon, the beautiful Lyons Corner House heiress. The family seems to have had issues around food: Lord Lawson was very overweight, then famously shed stones and wrote a diet book, while his wife was extremely slender. 'My mother had an eating disorder,' says Nigella, matter-of-factly, biting with gusto into fried baby eels. 'I don't know whether it was anorexia or bulimia.' She used to dish out huge meals to her offspring, and Nigella reacted by refusing to eat at all and was made to sit until she finished it. She hated her childhood. 'I was never a joiner, and childhood is all about joining in.' She went to five different schools and became so withdrawn that her mother thought she was autistic. 'When I finally left school, I remember thinking that nothing could ever be so awful again.'

She was wrong, of course. Her life has been blighted by the deaths of those closest to her. Her mother died of liver cancer at the age of 48, her sister Thomasina of breast cancer at 32, which was the death that Nigella says she found hardest to cope with. 'We were just so close... interdependent. Now I find I've become much more like she was; she was more outgoing and I've taken on some of her characteristics.'

In similar vein, the diagnosis of her husband with throat cancer in 1997 forced Nigella further out of her shell. Diamond could no longer speak, so she had to do it for him. Despite her previous experiences, she was hopeful he would recover. 'I really thought he was going to beat it,' she says.

Diamond dealt with the disease in public, writing a newspaper column about his ordeal. He was widely praised for his bravery and willingness to tackle the taboos surrounding cancer, but Nigella feels ambivalent. 'I don't think it was helpful for him. You can't deal with cancer in 800 words a week. He put all his energy into his column and I don't think he was prepared for dying.' Diamond also participated in a TV documentary about his life. 'John told me they wanted to make it, and I said, "Absolutely not",' says Nigella, 'and he said, "I've already said yes, and it would help me." Of course, I would have done anything to help him, but I don't know if I regret it or not.'

This documentary, she feels, allowed the public to feel proprietorial of her and her love life. 'I can understand why people feel like that,' she says. 'People saw inside our life and I think it made them believe they knew the script. But you can mourn and carry on with life at the same time.' Before his death, Diamond famously urged his children to ensure their mother married again. But Nigella is happy with the status quo. 'It's very childish but I quite like having a boyfriend.' Still, she's wearing an enormous aquamarine ring, from Saatchi, on her engagement finger. 'I'm not engaged,' she says. 'I've never been engaged. I can only get married in a hurry; thinking about it just makes me more aware of the pitfalls.'

Would she want more children? 'I'd love another baby,' she says. 'I like being pregnant. But if I started again, I'd almost feel I had to have two. And I like my life as it is. If I were younger, I'd say I'd do it in another two years, but I don't have that time. And I feel I've done my genetic duty.'

She laughs, then adds seriously, 'I think when you're a woman, it's very hard to be in love with someone and not want their child.'

And is she happy? Nigella dips a last doughnut into the melting knickerbocker glory. 'I have slight twinges when I admit I'm happy,' she says slowly. 'You know how alcoholics have to take one day at a time? I have to be happy one day at a time.'

Forever Summer by Nigella Lawson (Chatto & Windus, £20)