Those who've been learning for a year or two have built up an extensive wardrobe of jingly, floaty things from charity shops, while newcomers are in leggings and tee-shirts, with a token glittery scarf around the hips.
"There's no pressure on anyone to dress up. I tell them to come along in anything comfy, but after a while they want to look the part," explains teacher Zia, a former professional belly dancer who, gloriously attired in wafty blue and gold, jingles wherever she goes.
On goes the hypnotic middle-eastern music and the session begins with conventional warm-up exercises (incorporating some snake-like pelvic gyrations and graceful wrist and finger movements). Then everyone grabs a big, brightly coloured veil which they swirl around as they move about the floor.
There are no specific techniques because, in Zia's opinion, belly-dancing is a natural expression of femininity that comes from within.
First the class dance in a circle, imitating Zia's movements, or do their own thing, then progress to veil work, which makes the movements soft and flowing. Finally, before the closing stretching exercises, comes a "free" session in which everyone responds to the music in their own belly's way.
"I've run, I've done aerobics, I've swum, but everything else is dull compared with this," says teacher-turned-homeopath Alison Pollard.
"It's a chance to do something girlie in a non-competitive atmosphere," says Eve Morris, a 46-year-old graphic designer. "And it gives me street cred with my daughter's boyfriends."
Nicki Household This class took place at the Parkshot Centre of Richmond Adult andCommunity College in Surrey. Tel: 0181 891 5907.