It's no surprise that the mums have turned out in force to chaperone their kids at Britney Spears' show at Tokyo Dome: They've seen her recent, more raunchy videos, witnessed her fondling a huge snake during her performance at the MTV video awards and noticed that on her third and latest album, "Britney," she's cut down on the "oops" and "babys" and introduced words such as "hell" and "damn." Something's up, surely, and they want to be on hand to find out exactly what.

No longer the cute, innocent girl-next-door whose worst sin (apart from ex-boyfriend Justine Timberlake) is a navel piercing, Britney tonight gives her Japanese fans a show that is maybe better-suited for the grown-ups than the kids, and a little more Marilyn Manson than teen idol.

OK, it's hardly "Britney Live -- Welcome to Hell," but, having turned 20, the singer is desperate to show us she's no longer a girl. Instead, she's decided to be a little devil and dabble in some dark stuff.

The show starts with columns of flame shooting out of the stage floor and a spooky, rapid-fire "Requiem for a Dream"-style montage of video clips on the two screens flanking the stage. A multitude of people flash on and off the screens talking about their dreams, culminating in Britney saying, "It's a dream come true."

Then she appears on stage, clad in black, and strapped crucifixion-style to a huge, spinning pinwheel. After being freed from her bindings by a group of scantily clad dancers, she launches into an ear-splitting rendition of "Oops! I Did It Again." It sounds like an industrial-metal remix by Trent Reznor, but we're going to have to get used to the horrifically tinny wail of noise with the bass completely sucked out of it 'cause this is the Tokyo Dome.

When the "song" ends, Britney attempts to flee the stage but is captured by a bunch of vamps in tiny, zebra-patterned hot pants who tie her up with a rope while writhing around her like they learned their moves from lesbian S/M flicks. (Of course, if Britney is gay, then her no-intercourse boasts make much more sense.)

As Britney escapes backstage for the first of many costume changes, an invisible female narrator with a measured voice as chilling as Elven witch Galadriel in "Lord of the Rings" begins an inane fairy tale. But it's drowned out by screaming kids as Britney returns in white hot pants -- emerging from a massive music box and dancing wildly through a high-energy medley of "Born to Make you Happy," "Lucky" and "Sometimes."

Galadriel ends the story with, "She knows deep down in her heart that he will find her and they will make love until the end of time," and 60,000 virgins screech as if they've all guessed how painful an eternal bout of tantric sex would be.

And then Britney is back -- in black again -- and continues the sex theme, singing about something she allegedly knows little about. "Boys" is the song, and the way she bends over and shakes her reportedly surgically enhanced cleavage at us, while a big muscular dancer stands right behind her making hip-grinding motions, suggests that she knows a little more than she's been letting on.

On this evidence (and the show's not over yet), it seems just a matter of time -- maybe minutes -- before she tosses away her virginity, if she hasn't already. One thing's for sure, SHE IS NO LONGER A GIRL!

It's not all subversive, of course. Britney often appears as an angel of light, her Bambi-like eyes and coy smile flashing up on the screens. And during the musical highlight -- "I'm Not a Girl, Not Yet a Woman," of course, a classic pop tune that Britney carries brilliantly -- your correspondent is bewitched, the hairs pricking up on the back of his neck while he punches the air and sings along.

While this crowd is so easily pleased it would probably raise the rafters even if Britney spat "I hate you all and I hope you die," Miss Spears is not winging it. All those teen years in drama school have obviously instilled in her the knowledge that to succeed at this level, you need to be slick and disciplined. That she is -- but it's not just singing. Each song is a five-minute dance workout that would kill anything less than a professional athlete.

The only real bummers tonight -- apart from the acoustics and her backing band's instrumental -- are when Britney leaves the stage for breathers and the costume changes and we're left enduring mindless videos, the worst being a drawn-out skit of a bunch of dumb teens with guitars talking about forming a band in their bedrooms.

But, anyway, here's Britney again, now driving round the stage in a huge pink cardboard Cadillac. The words to "Anticipating" flash up and she invites the kids to join in a mass karaoke session, which is how some cynics might describe this whole event. But for this she gets the biggest mass-screech of the night, even though Britney misses the first line of the song -- which at least proves she isn't lip-synching.

"You were really really good," says Britney. "Now I want to ask you a question. Have you ever heard a song that opens your body?" Now, what would Britney know about that . . . ?

Suddenly she quits the Cadillac and, clad in a minuscule grass-mini and a tiny green bra, delivers "I'm a Slave 4 You" while writhing around a 3-meter silver pole just like a dancer at a wallet-busting Roppongi men's club. Her dancers, meanwhile, kinda open their bodies on the floor around her by mimicking bouts of missionary-position copulation.

For the encore, "Baby One More Time," an impressive 15-meter-high holographic image of Britney is projected onto the stage as she descends in a metal cage. Flames shoot up again, a ton of firecrackers go off, Britney coyly mouths "Goodbye" and Galadriel informs us, "It was just a dream, a dream within a dream."

Britney's real dream, of course, is to be the next Madonna. And this tour shows she's wasting no time in ditching her teen-pop image and getting more risque in a bid to reinvent herself so these fans -- who'll soon be donning kimonos for coming-of-age ceremonies -- will still adore her.

OK, she might not quite be ready for the "How-I-lost-my-virginity" coffee-table book, complete with tasteful but racy black-and-white photos a la "Sex," but Britney is taking her first tentative steps into the real world of adult careerism.

And at the same time she's giving herself a little taste of the hell that goes hand in hand with that. Namie Amuro -- standing emotionless behind me with her date Sam -- was probably making mental notes.