It was as if they had never been away. They haven't really, having spent the last decade releasing varyingly successful solo singles, publishing books, acting a bit and gazing out from gossip magazines in the company of boyfriends, husbands, children and George Michael.

But it is only when you see all five Spice Girls together again, at the start of the epic London leg of their world reunion tour, striking poses in front of thousands of flashing light sticks and David Beckham, that you recall exactly how huge they were a decade ago.

Were almost all these songs really number ones? Did the whole world really fall as one for a single with the word "ziga-zig-ah" in its chorus? Did Geri Halliwell in a minuscule Union Jack dress really once symbolise all that was Cool about Britannia?

Yes, yes, and yes again. This weekend, beneath a blinding lightshow, dressed as boxers, jazz singers and themselves 10 years ago, they worked their platform boots off to prove that the magic had not vanished and lives could still be spiced up.

In Pictures: Spice Girls at the O2 Arena

Shimmying and bouncing (apart from Emma Bunton, whose recent ankle injury hindered her slightly, and Victoria Beckham, who is far too refined for that sort of thing) they romped through the Motown pizzazz of Stop and chirpy R&B of Say You'll Be There. Old rivals Halliwell and Melanie Brown pretended to fight but more often they hugged, and smiles were wide on all sides.

Each girl had a solo spot, though only Bunton and Melanie Chisholm, who enjoyed the longest post-Spice careers, performed original singles. Halliwell camped it up in red hotpants with It's Raining Men.

Brown donned leopard print to roar through a cover of Lenny Kravitz's Are You Gonna Go My Way, while cracking a whip and tying a giggling male audience member to a sort of torture stepladder.

Posh chose not to sing solo, instead performing a catwalk vamp routine in front of pretend paparazzi. But her solo lines in other songs received the biggest cheers of the night, perhaps because she needed the most encouragement, perhaps just because she is the most famous.

The energy only flagged during tracks from the Geri-less third album and dreary new single Headlines (Friendship Never Ends). Otherwise they were as sparkily entertaining as in the old days, giving their all to earn the staggering fees they will receive.

What is the Spice legacy? Not much. Kids today may well believe that Girl Power means marrying a footballer and going shopping for a living.

The lofty chart positions of tracks such as Let Love Lead The Way belies their forgettable nature, and though I've tried hard not to mention the movie, it really was a stinker, wasn't it?

Unlike the Take That comeback that prompted this one, genuinely great new material does not appear to be forthcoming. This was not a resurrection, it was a history lesson. But they made learning about the past a lot of fun.