NEARLY 10 years ago, I interviewed Nigella Lawson at the house she then shared with Charles Saatchi.

By mistake, I went in through the wrong door, which was opened by someone I think was a nanny. As a result, I stepped into the wrong part of the celebrity chef's life, the part which had not been created for media consumption. There was nothing particularly incriminating about what I saw - no lines of coke on the cabinets, or skeletons edging out of cupboards - just huge, palatial rooms, dominated by giant artworks, a ping pong table, a fridge and a couple of tourists standing in the corner, which turned out to be Duane Hanson waxworks.

Nigella appeared on the stairs, bewildered, in a man's dressing gown. She told me I wasn't supposed to be here, but in some other part of the building; that I should have come in through some other entrance. Soon I was led down a series of labyrinthine passages into a whole other world, of gleaming kitchen spaces and smaller, more intimate rooms. Here, I was introduced to the (now dressed) domestic goddess I was meant to meet.

At the time I didn't think this was much of a surprise. It had always seemed to me that the Nigella we saw on television or in her books was an escapist fantasy, not designed to be taken seriously - she herself described her persona as ironic - and certainly not, despite all the tales about cosy suppers and having friends round for tea, to be imagined as the real deal. Nigella was a creation, rather like the Hollywood film stars of yesteryear.

Yet, looking at media reactions to claims that she was a habitual drug user, one would think she had duped us, and that the nation is in a state of shock to find that our beloved Nigella is, possibly - if the allegations are true - a drug user. That shock, I believe, is a little fake. It's just another titillating story.

The evidence read out in court last week, during a fraud case launched by Lawson's ex-husband, Charles Saatchi, against former assistants Francesca and Elisabeta Grillo, suggested a different version of the fantasy chef. It's not the first time the bright, airy lightness of the Nigella brand has been punctured. More genuinely horrifying were the photographs, in June, of Saatchi seemingly clutching her by the neck in a Mayfair restaurant.

I don't think I'm alone in not being so very shocked, in a world in which countless celebrities are known to have had drug problems, by allegations that Lawson may have had a coke habit. What I do find shocking is the glimpse we are being offered into the sheer excess of the rich and famous. It's breathtaking, for instance, to hear about the Saatchi-Lawson household spending £100,000 a month on credit cards - much of which was allegedly spent by the Grillo sisters. I didn't see the house that Nigella moved out of earlier this year when she and Saatchi split up, but I have read of how their most recent home had whole sections for different members of the families, and independent kitchenettes for the children. The cosy image of family life, based around a convivial kitchen, is among those inventions left threadbare by these revelations.

We now see two ­Nigellas existing in the public world. There is the domestic goddess still out there, online, telling us about her holiday hotcake recipe, sharing the run-up to Christmas with us and serving up recipes like pre-baked comfort tweets. That Nigella seems impervious, but for one tweet saying "thanks for your support", to what is happening to the other one, now caricatured as "Higella".

Can brand Nigella go on? Who knows? The allegations remain unconfirmed. In America the second series of her show, The Taste, is still due to air, and there are countless stories of celebrities who have emerged from scandal - from Kate Moss, who once commented that her own drugs scandal didn't seem to have had any impact on her earning power, to Martha Stewart, who managed to come back after a prison sentence for insider trading.

As the grubby allegations emerge, it may seem as if we can never again quite believe in the Nigella myth. But I've always thought falling for that whole domestic goddess act was an act of wilful suspension of disbelief. And people could still suspend that disbelief right now, even after all the allegations. They could do so because, in fact, a little darkness was always the unspoken backdrop to her perfect bakes.

Indeed, the reason there has been so much fascination with this story is that we are actually captured by this darker side of the domestic goddess as much as we are to the cosy fantasy of kitchen bliss. It is an old story, one that dates back to the creation of the fantasy of the perfect 1950s housewife and the feelings of frustration and depression Betty Friedan chronicled in The Feminine Mystique.

Any domestic goddess, in other words, is always going to have her own private hell - and we knew it was there for Nigella. It was always a well-known part of the story that she had lost not only her husband, but her mother and sister to cancer. She didn't shy away from discussing death and these aspects of her life publicly. Indeed, some of the things we've always loved about Nigella - what she called, when I interviewed her, her "pathological greediness", her lack of "caution" - are not without their darker sides.

What we are seeing made public, sadly, is the tragic tale of the end of a marriage. But I suspect we are not seeing the end of Nigella. Nor is this the end of the domestic goddess's hold on our imagination. We simply like her too much, warts and all.