"Did you notice the carpet?" asks Mariah sternly. The carpet in question covers the lobby of the mid-market Leicester Square hotel, four floors below the bog-standard room where she is holding court. Said carpet is festooned with images of butterflies, a creature Carey so identifies with that she named her 1997 album after it. "I refused to come here until they did specially. They were working on it all night for me."
Really? Heavens. The woman who won the World's Best Selling Female Artist of the Millennium at the 2000 World Music Awards crumples in a fit of giggles.
She is, of course, joking. She dives onto the bed that dominates her room, kicks off her high-heeled shows ("Ohh that's better; killing my feet, they were. You don't mind do you?"), lays on her side and grins.
She seems quite nice, this Long Islander who turned 35 on Easter Sunday, whose fortune runs into nine figures and whose reputation not so much goes before her as proclaims her to be part Cruella De Vil, part Elizabeth Taylor and part your worst nightmare. Why, according to the British tabloids when she descended upon the five-star boutique hotel where she is actually staying for a 3am check-in, she had demanded to be greeted by three-foot candles and a red carpet. Except she hadn't.
"Well, it happened," she admits. "But I didn't ask for it. Like I'm going to be on the phone to the head of the hotel going 'darling, listen, don't even think about inviting me to stay without the three-foot candles'. Who even knew three-foot candles existed? Did you? I wouldn't have noticed if it was a purple carpet with polka dots on it. I'd just got off a plane and it was three in the morning. Trust me; my only thought was, 'where's the bed?' Funnily enough, there was a rumour that I refuse to walk on carpet. Now, it seems, I can't get enough carpet. I love finding out my latest quirks."
The lunchtime after her red-carpet arrival, Carey attended the Capital Radio Awards. Reports varied as to whether she was an hour or 90 minutes late. All, however, were agreed that she was delayed by the calamity that is a broken fingernail. So she was.
"Look at it," she insists, proffering a regal left hand. With the aid of the Hubble Telescope it might be possible to see some imperfection in one of her beautifully manicured nails.
"That's my point!" she smiles. "Hardly anyone knows this but when I was in 11th Grade, I went to beauty school I could give you a manicure, a pedicure and a facial so I can fix my own nails. We didn't have the right powder, so I said I'd do it the next day and I did. There's no way I was an hour late. Can you imagine what it's like that you break a nail and it gets in the papers? If I get mad about it, they're just going to write more. Then it'll be Mariah Has Tantrum on News At Ten."
Although it must be stated for the record that she was 93 minutes late for our meeting and she speaks of being "in a moment" slightly too frequently, you'd like Mariah Carey. She is terrific and tactile company; she has a filthy laugh and she is keener to dispense compliments than receive them.
Her tale would seem far-fetched in an American TV movie. The girl with the golden voice, head-turning beauty and fierce ambition had a peripatetic, financially deprived childhood, scarred by a sense of never quite fitting in.
"I always felt ugly," she explains. "It was difficult being bi-racial. I didn't look like my white friends with their straight blonde hair and blue eyes but also I didn't look like my black friends with their beautiful, gorgeous skin. I was always the girl in the middle with weird hair."
The awkwardness soon disappeared. Aged 19, Carey was discovered by Tommy Mottola, boss of the multi-national Columbia label. He signed her, he married her and he helped her into a superstar.
After the rise came the inevitable fall: divorce, a (sort of) nervous breakdown, relative failure and ridicule. Finally, there is redemption via a musical renaissance culminating in her 10th album, The Emancipation Of Mimi. The only constant in the morality tale that is her life has been the constant sneering: she's dull, she's dim, she's a diva.
"I don't understand that," she admits. It's a sexist thing, honestly. If a man say, Mick Jagger, is regarded as a sex symbol not that I'm calling myself a sex symbol, perish the thought do people doubt that he writes and sings his songs as they do me? I bring the melody, I bring the concept and I bring the lyrics to my songs. I've always been fully involved in my music. Always."
That may not be in doubt. Less clear is why she should be so staggeringly popular. After all, others have the looks and the songs and who wouldn't relish being greeted by a platoon of three-foot candles?
"I don't know," she confesses. "I've worked very hard but because of my songwriting my fans relate to me on another level. They hear the personal songs such as Looking In from Daydream, Close My Eyes and Outside from Butterfly or Petals from Rainbow where I talk about things that have happened to me. A lot of young women relate to these introspective, really honest moments about childhood and overcoming difficulties. That's why I have such a connection with my fans.
"When people say 'your song got me through a moment in my life', that is the validation, the real moment of glory, because you've actually touched somebody's life. I always said that if I become famous, it would validate my existence. It didn't. Instead, the fans compel me to keep going."
Those fans were desperately needed in her darkest hour. After a lavish ceremony in 1993, her marriage to the domineering Mottola soon turned sour.
"When you're married to someone who's also the head of your label; when his best friend is your lawyer and his lawyer; when your manager used to work for him and when everybody around you is on his payroll, it's a difficult situation. For a young woman to get out of it is a feat. What I'm really proud of is that I paid for half of everything in our mansion, down to the lighting bills and the water in the refrigerator. I know that I was never kept by anybody. Overall though, I really do look at what happened as a blessing because I had to go through everything so I could write about it and other people could find inspiration. I had to stop with all the worrying and rise above all the negativity that person had brought to my life and to the people around me."
By the time they divorced five years later, Carey was emotionally spent and had what is routinely referred to as breakdown. "I was physically and emotionally depleted from having to fight constantly."
She fled Columbia and signed to Virgin for $80 million, the biggest recording contract in history. Her Virgin album, Glitter, was released on September 11, 2001 and promptly disappeared. Having followed her wallet rather than her instinct, Carey was soon paid off and moved on. "Anybody would have taken that deal but now I realise that Virgin weren't equipped to deal with the type of music I make."
When she surfaced with 2002's Charmbracelet, "that whole moment was about this supposed breakdown. People wanted me to talk about it and to cry on television with Oprah. People were whispering 'be vulnerable' in my ear. People cloud your perceptions sometimes especially when you don't want them to think you're a difficult diva. Ultimately, you have to trust your gut."
The joyous experience that was recording The Emancipation Of Mimi (Mimi is her pet name) has completed her recovery.
"I'm in the best state I've ever been in. I'm in a great moment. I'm very excited and it's a really great time for me."
Not bad going for a woman who, when she isn't demanding red carpets, three-foot candles and breaking fingernails, legendarily refuses to use stairs.
"Yeah right," she giggles. "I'm the complete opposite. Actually, I've been stuck in elevators in Germany, in Japan and in my own apartment close to where the World Trade Center used to be, so I really, really hate elevators.
"But I go in them when I have to. Here in Britain, the elevators seem to be much smaller than in America, so it gets me feeling even more uneasy. All the time I'm saying 'can't we just take the stairs?' I'm always about stairs unless it's 20 flights. I even use stairs when I'm in my heels. Sometimes, I just don't know what people are talking about."