Asylum studios, Perivale: just before leaving for America, the Spice Girls film the video for "Mama," their forthcoming record-breaking fourth number-one single. It it shot in front of hundreds of children. (The video concept: a kids' TV show.) Between shots I listen to two kids talk. The little girl points nervously as Mel B.

"The Scary Spice isn't black, is she?"

"Yes she is," the little boy next to her asserts.

The girl considers this. "Not that black," she says.

And I think: "Scary Spice" doesn't actually seem like a very funny name when you actually hear someone say it.

The children are taught simple dance routines. Speckled in their midst are the occasional parents. I watch one in the second row, sitting cross-legged, shyly echoing most of the half movements with the youngsters beside her, but skipping the more demonstrative above-the-head flourishes. This unnoticed Spice Girl fan mother has done hand movements like this before. I wonder what she is thinking. Once upon a time she was down there on stage, looking up. Her name is Shirlie. As in Pepsi. And as in... Wham!

What's your favorite word?

Victoria: I quite like "bollocks". That's quite an expressive word.

Geri: My favorite would probably be [she stutters as she says it] "existentialism", I can't say it and I'm not quite sure what it means.

Mel B: I have been using "higgledy-piggledy" quite a lot... and "hotchpotch" I use. I don't know why. Maybe it's a Leeds thing.

Emma: "Candyfloss". Candyfloss is quite... I don't know. [laughs]

Mel C: Probably "sound". I seem to say it a lot.

Mel C has got a scar on her head from when she bashed herself on a chair as a young kid. The social services came round, thinking that her parents had beaten her up. She remembers the cats. She used to talk to them, and that was when, if she was feeling greedy, she would eat their food as well. "My mum used to find me in the garage eating the cat food." (Whiskas? "My favourite, yeah.")

Mel C's parents met in the Cavern in Liverpool. He used to fit and repair elevators for Otis, the elevator company. She was always a singer and still is. Mel C's mother can still be found singing in clubs fronting a band called T Junction, singing songs by Tina Turner, Bryan Adams, that kind of thing. Her parents split when she was young. "I think I was a bit too upset to talk about it," she remembers, "and a bit confused."

Mel C used to have this thing where she thought that the only person living a normal life was her. It was all about her. And everyone else, they weren't real people. They were just watching her. All the time. When she was alone in her bedroom, the whole world was watching her. When other people went home, they didn't watch telly, they watched Melanie.

"But I've sort of got over that," she says.

She always wanted to be a pop star. "I thought I would change completely as a person. You'd never get any spots, silly things like that. I would never be unhappy again." Silly, silly. "And then your song goes to fucking number one and you're miserable. We all have moods together and we were in Japan and all really down."

The other day, Mel C got a marriage proposal. He was 12.

The Spice Girls arrive in New York during the last week of January. They are here to Do Promotion. This is the sort of thing which happens: tonight the Spice Girls are to spend the evening being driven around new York on a bus, accompanied by about 20 radio station competition winners, some of home only have the vaguest idea who the Spice Girls are. Along the way, they will make various stops - one at a restaurant for help-based appetizers, at the Great American Backrub for head massages, at another restaurant for drag-queen-delivered main courses. Occasionally one of the Spice Girls will speak live on the phone with the radio station, Z-100, who have arranged all of this, but very little of what is happening will ever be explained over the air.

The Spice Girls are tired, and they are passing around illnesses. Two of them have already had the flu on this trip. Now it is Victoria's turn. I suspect tonight's contrived hi-jinks wouldn't be much up her street anyway. "It's not the number ones," she says, deadpan. "This is the highlight."

Emma joins us. Down the bus, one of the competition winners screams at some minor pleasure. Emma sighs. "Everything's over-exaggerated here." She shares some reservations about her public image. "I don't want to be a cutie. I want to be a sexy bitch. I want to be a hot sexy bitch."

You never like being a cutie?

"I like it sometimes. I can get away with murder."

"I'm going through hell this evening," says Victoria. "Flu on a party bus full of Yanks. Nightmare on wheels." Someone hands her the mobile phone. Suddenly she is live on Z-100. "I'm doing very well," she hollers, in full the-Spice-Girls-are-up-for-it voice. "I can't believe you're not at this party!" she tells the DJ at the studio. "You're missing a fantastic night!"

Interview completed, she smiles wearily at me. "See the sincerity?" she says. "Maybe I'll get the lead part in a film after all."

Someone passes round a book. George Orwell's Down And Out In Paris And London. It's Geri's.

In the back corner, Mel B is offering some psychotherapy to a sad boy. It's slow going.

"What have you got to be sad about?"

"It's complicated."

"Why are things complicated?"

"I don't know."

"Why are things complicated for you?"

"They just are."

"It's because you make them complicated," she tells him. He goes to the bathroom. "I'm being a therapist - I love it," she tells me. "He's a teacher and he's all stressed out. He's finished with his girlfriend and he thinks that's the end of the world." He returns.

"You're too logical, you are," she tells him. She is sitting up on the back of the seat, her feet on the cushions.

"Why are you sitting up there?" he says.

She jumps down next to him. "So I'll sit down if it makes you afraid."

"No, it's..." He can't finish this sentence. The nervous teacher has a rather different agenda - to hell with the old girlfriend - for this conversation. But Mel B will not be distracted. She has worked out that he really wants to be in the theater, and picks apart his arguments for doing nothing, one by one. "Why don't you start drama classes on Saturdays?" she says, impatiently.

Emma asks me if I've had one of the massages.

They're just for pop stars, I say.

"I'm not a pop star," she says.

Victoria nods. "We were discussing it the other day. 'Pop star'. 'Famous person'. 'Celebrity'. We decided we want to be ' a household name'. Like Ajax. We want to be a Fairy Liquid or an Ajax."

Mel B now has a larger male harem. "You're not drinking any more," she tells one. "I don't want you yucking all over the bus." She is sitting on a bench. The men are standing in the aisle, lined up in front of her. "Look," she chortles, "a whole row of knobs. Which will I kick the first?"

Z-100 plays "Wannabe" and it echoes through the coach. You'd have thought they'd be sick of it. But Geri and Mel B jump up, and bounce and bend and holler in the gangway, singing along to every single word.

A conversation about the media and sex.

"I find it frustrating sometimes, and we've had a lot recently, where things just get reverted round to sex all the time," says Mel C.

"I don't mind that," says Mel B.

"And a lot of innuendoes and stuff," Mel C continues. "And that frustrates me because we're not about sex. It might come into the equation. It'd be naive to think..."

"But everybody does sex!" shouts Mel B. "Sex is the world!"

"I mean, when people are treating us as a product, and we sell sex," argues Mel C. "And we don't sell sex. We write music. Sex is part of it, I know, but I don't like it when people see sex..."

"The other day," Geri interrupts, "when we had to do all these phone interviews..."

"Yeah," nods Mel B. "That was annoying, because they were all men."

"...normally one might be a little risque and then the other is a big kiddie thing, and there's a real variety," Geri continues, "but the other day we did 15 different radio stations, real middle America, and they were completely obsessed with sex. And after a while the joke was wearing thin. I was really surprised, because in America it's all very under the carpet. But I think that explains it: it's when you're not having sex you talk about it all the time, don't you?"

Continue to part four...