If the wages of sin is death, the wages of fame in the 21st century would seem to be a long, lingering roasting in the laser glare of the media spotlight. And the process is starting earlier all the time, as the queue of wannabes, eagerly fluttering like moths around the flame to receive their dose of ritual humiliation on the weekly Popstars TV series, are finding out to their cost.

I think it's such an exploitation of those poor kids, says Melanie Chisholm, no stranger to the audition process herself before becoming a Spice Girl and now a solo star in her own right.

To be honest, I think the ones who haven't got through are the lucky ones. Mel B and I were talking about it the other day, and we both agreed how glad we were that it wasn't us, which it could so easily have been. Those kids are going through hell and the way it's set up they won't have anything to show for it.

Ironically, it was the Spice Girls - initially convened in 1994 through an open audition ad in The Stage magazine - who were in no small part responsible for sparking off the craze for "instant" pop bands and the rise of the latterday uber-celebrity.

But having tasted the fruits of fame, including financial rewards beyond most people's wildest dreams, Melanie Chisholm has since felt the uncomfortable heat of the media spotlight more fiercely than most. After a year in which she has suffered and recovered from depression, an eating disorder and the wheels finally coming off the Spice Girls bandwagon, she was forced to postpone her solo British tour last month because of a viral throat infection.

The specialist told me that if I went ahead with the tour, as planned, I probably wouldn't get through it, and also I might never sing again. It wasn't a particularly difficult choice to make.

What she found a lot harder to take were the subsequent newspaper reports which insisted that the real reason she had pulled the shows was that she was still in the grip of a clinical depression, and was psychologically too fragile to go on tour.

I don't read the tabloids any more, which is very good for my health. But no matter how long I've been in the music industry and no matter how much rubbish I've had thrown at me, they still piss me off. I'm fully recovered from my depression, so why are they trying to drag me down again? I'm sure they had a lot to do with it last time. I love touring, that's my refuge. For one thing, when I'm abroad it gets me away from them.

With the rescheduled dates announced today and her voice back to full strength, Chisholm is once again in bright and bonny form. Wearing brown-rimmed glasses and dressed in jeans and a black, sleeveless T-shirt, she is now what would be considered a "normal" size in any walk of life other than the stick-insect world of modern showbiz.

Her tattooed forearms and biceps are obviously a lot more powerful than your average secretarial type, the result of the obsessive training and weight-lifting which helped her to maintain an unnaturally slender figure for so many years.

I got very obsessed with health and fitness magazines. And my diet became so limited that at one point I was eating no protein, no carbohydrate, and God knows how I survived on the schedule we had with the Spice Girls. I think I was living on adrenaline. Eventually I was exhausted and my body just snapped. It was like a catapult that had been stretched as far as it could go and then it was suddenly released. Then came depression, bingeing. I couldn't exercise because I was so ashamed of myself. The weight piled on. I went through a period of hating myself.

While sympathising with her plight, was it not the case that the Spice Girls themselves were guilty of contributing to the pressure on young girls to conform to a skinny stereotype?

I think we were victims of it, well Geri and I were. I think overall the group had quite a healthy difference in shapes and sizes and the other three girls were just naturally the shape they were. Maybe I'm guilty of putting pressure on little girls who loved Sporty. But if so, I was a victim of previous people who defined how I thought I had to look to be accepted in the pop world. Perhaps it was a case of the victim becoming the perpetrator, which is a pattern you often find.

With the help of prescription drugs, therapy and the moral support of family and friends, Chisholm eventually dragged herself back to full health, but whether due to the illness or to other adjustments in her circumstances, a change seemed to have come over her along the way. Whereas she had once been the quietest of the Spice Girls, happy to go along with the policy decisions and media statements issued by the more powerful personalities of Geri Halliwell and Melanie B, in recent times a more confident, garrulous side to her personality has emerged.

At the launch party for the Spice Girls latest album, Forever, last November, she revealed a bolshy streak that took most observers by surprise, regaling various journalists and photographers with a heroic display of forthright epithets and two-fingered salutes that put something of a new spin on Girl Power.

I didn't want to go to the launch party, because although I love the Spice Girls, I hate the media circus that surrounds them. I wasn't prepared to be nice to certain journalists because they'd been openly disgusting to me and my friends, so I just told them to fuck off and get out of my party. And I was angry that the other Girls were being polite to them. I didn't want them to do that. I'm sorry if that's not very professional, but my standards are higher than that. I thought the whole party was a pile of shit, so I decided to get very drunk. And when I went outside and the paparazzi were there, I simply thought I'd show them what I thought of them. And I don't regret it one bit.

It's all a long way from the conciliatory tone and ultra-bright, kids-friendly style of the Spice Girls in their heyday, and with Geri now long departed, it is clear that Melanie C has become very much the loose cannon on the deck. Part of her reluctance to toe the group line is possibly a subconscious reaction to her success as a solo act. Her own album, Northern Star, has now sold two million copies, as many and possibly even more than Forever.

The difference is that whereas Chisholm's album is perceived as the successful foundation of a future career, the Spice Girls latest offering has been regarded as the underperforming swansong of a group that is on the skids. Isn't part of Chisholm's problem that she feels torn between wanting to get on and pursue her own career while not wanting to "do a Geri" and leave the other Spices in the lurch?

In the beginning I didn't much mind not getting my opinion heard because I was quite young and I was scared anyway, but as I grew older it started to niggle me more and more. Then, as the solo work went on, I was saying things in interviews that the Girls weren't too happy with. But I want to be an individual.

I don't want people to know me as 'Sporty' the rest of my life. I'm Melanie. And this is what Melanie has to say. But I would never 'do a Geri'. What she did was shocking to all of us, because it was a lack of communication. I mean, c'mon, Geri is such a fantastic talker - it was just mindblowing that she walked away with nothing to say.

It is a rare moment, in her current mood, when Chisholm has nothing to say. She talks in such a rush that the words come tumbling out almost too fast for my recording machine to scoop them all up. The transcript of the interview is about double the average word length yielded over the same period of time.

Little bits of gossip surface, here and there. She cheerfully announces that she has recently been dumped by her latest boyfriend Dan Williams from the boy band Tomcat. She now has ten tattoos and wonders whether that makes men frightened to approach her. She regards herself as fearless in most situations except where spiders are involved.

She lays the blame for the disappointing sales of the Spice Girls album at the door of the group itself.

I think it's a good album, but we didn't work on it as hard as we did on the others. We barely did any promotion. If you want to sell loads of records then you have to do a Westlife and fly around the country and do a big media thing. We're all too tired to go through that again.

Did their new R'n'B direction cause them to lose touch with their pop fans?

We felt it was time to move on and it seemed the healthiest way to go. I love all the things the Spice Girls have done, but I'm 27 now. I feel a bit old to be singing "Zigazig-ha". How long can you sing that? Just the thought of it exhausts me.

The Spice Girls currently have no plans to tour or release a second single from the Forever album. So is it now time to start talking about the group in the past tense?

We've got no plans to make another record. But we've got no plans to split up either.

So are the Girls still functioning as a group?

We're not not together, but we are not actually doing anything.

I see. What does that mean?

We're still together, but we're just not working. So that's the way that it stands.

Right! So what, after all that she's been through, does Melanie C really, really want now?

I want happiness in whatever form it might take. Even if it means not singing any more. I just want to be happy. Because I've been unhappy for a very, very long time.