When the Spice Girls closed the Olympic Games, tumbling out of their glittery taxis in short skirts and too-high heels like the kind of hen party you might cross the road to avoid, they instantly stole the show. Their appearance provoked 116,000 tweets per minute, more than Usain Bolt winning the 100m final, more than Andy Murray's first gold medal, more in fact, than any sporting moment of the previous fortnight.
They always were terrible attention-seekers. And with one five-minute medley the Spice Girls proved that they still know how to put on a show. And that when they do, people still watch – in their millions.
That's what the cast and crew of Viva Forever!, a new West End musical inspired by the girl group, are banking on as they prepare for opening night next week. In a theatre scene saturated by jukebox musicals, this is the big one, produced by Judy Craymer, the brains behind the global juggernaut in spandex that is Mamma Mia!. Not a single zig-a-zig-ah has been harmonised but it has already taken £4m at the box office.
Sixteen years on from "Wannabe", the Spice Girls are back. In truth, for those of us who grew up in the Nineties, along with Ross and Rachel, the Trainspotting soundtrack and Alan Partridge catchphrases, they never really went away. I was 14 years old when they stomped on to the scene in their Buffalo platforms and my schooldays were soundtracked by Spice – from "Wannabe" at house parties to "Goodbye", which became our unofficial post A-levels anthem. I still know the dance routines to "Spice Up Your Life" and "Stop". Thanks to Posh, I held a pinstripe bustier to be the height of sophistication for far too many years. And to this day, the Christmas season hasn't truly begun until I've heard "2 Become 1" on the radio. So they left their mark.
Whether you agreed with the notion of Girl Power or not, the Spice Girls had it in heaps. Their debut single, "Wannabe", went to No 1 in 30 countries and they went on to sell 80 million records worldwide. They were – still are – the world's biggest girl band. Everyone who has followed since is but a pale imitation. Girls Aloud? Too homogenous, too glossy. The Saturdays? I can't name a single one, let alone be bothered to give them nicknames. As for Little Mix, their attempt at the Girls' eclectic blend is more insipid korma than Spicy madras.
The Spice Girls were trailblazers, a manufactured girl band, yes, but one in which you could still see the joins. They performed like pros but were never too slick – always singing and talking over one another, often falling out of their clothes and with each other. They didn't even come up with their own nicknames – that was Top of the Pops magazine. Attainable archetypes with regional accents and ready laughs, you could almost be any of them – Sporty one day, Baby the next.
Then there were the songs –"Wannabe", "Mama" and "Say You'll Be There" – many of them pop classics. Can they power a whole musical? If anyone can make it work, Craymer can. Mamma Mia!, now in its 14th year, has played to over 50 million people across the globe and taken $2bn at the box office. The idea for Viva Forever! first occurred to the producer when she met Simon Fuller at a dinner nine years ago. It wasn't until Geri Halliwell sent her a "sweet" note requesting a meeting that the project took shape.
From the off, she rejected a show about the Girls themselves. "I didn't think there was anything interesting in it. One married a famous footballer, one was blonde with bunches... No. I wouldn't have done it." Instead she set out her vision to Geri and Emma Bunton by sending them DVDs of Cover Girl and All About Eve, female-led Hollywood classics about chorus-line rivalries and the dark side of fame. Meanwhile, she drafted in Jennifer Saunders to write a script.
The result is Viva Forever!, a rags-to-riches tale of Viva and her three friends who upload a song-and-dance routine to YouTube and are subsequently scouted by a television talent show. As Viva is cherry-picked for stardom, she is forced to choose between friends and fame, while her relationship with her adopted mother is tested too. It doesn't take a genius to see where songs like "Wannabe" or "Mama" might kick in.
As is traditional with musicals, there is an uplifting moral, too. "Keep true to yourself, keep your feet on the ground and remember what's important in life. Don't get caught up and lose yourself," explains Hannah John-Kamen, 23, who will make her West End debut as Viva. One year out of drama school and currently starring as Rosa Maria Ramirez in the BBC's The Hour, she grew up singing Spice Girls songs into her hairbrush. Thanks to Martin Koch's sweeping orchestral arrangements, though, she has had to relearn them all from scratch.
While the songs sound different, there are clear parallels between Viva Forever! and the band's story. Like Viva and her friends, they were a bunch of nobodies who were thrust into the limelight. There are echoes, too, of the fractious friendships in the band. Craymer keeps a set of Spice Girls dolls in her office, which, it is said, she rearranges according to who is on speaking terms (or not) at any one time. At least, she says, they are all supportive of the musical: small wonder, with tickets priced up to £67.50, it could make each of them £5m in royalties.
"They're like squabbling sisters but they are very protective of each other," says Craymer. "When you get them all together in a room, it is quite powerful, if not overpowering. You can feel a chemical excitement coming off them." Whether that chemistry transfers to the stage next week is another matter. The 14-year old Wannabe in me will be hoping that it does.