Think the opening of the doors on the first day of a Harrods sale as a horde of screeching females barge and bully their way towards the bargains, all slam, bam and not so much as a thank you ma'am. Put them on roller skates, dress them in fishnets, gold lamé hot pants or mini skirts – not forgetting the gumshields, kneepads and helmets – and you have roller derby, one of the fastest-growing contact sports.
So fast that it will be in contention with more orthodox, and certainly less violent, pursuits such as golf and squash, which are vying with roller sports for possible inclusion in the Olympic Games of 2016. And next Saturday night the ticket touts will be out in force in Tottenham, not for a derby match at White Hart Lane but outside the local leisure centre down the road, where Britain's first-ever roller derby international, between The London Rollergirls and Canada, will be played before a capacity crowd.
Since the first roller derby league was launched in the UK two years ago virtually every match has been a sell-out, particularly in London, where some 50 women of all shapes, sizes, ages and nationalities whizz around an elliptical track in pursuit of points for each player they pass. If they can shove them out of the way, or even knock them down, so much the better. Hands, knees and plenty of boomps-a-daisy. It is speed skating with attitude for these hell-for-leather angels, and there are a few unladylike brawls between women whose more demure day jobs range from accountancy to psychology.
But once dolled up in their retro combat outfits they adopt alter egos, with accompanying stage names. London's line-up includes Sleazy Rider, Bette Noire and Grace of Wrath.
These are the ladies who crunch. It may not sound terribly Olympian, but with the new accent on "yoof" called for by the International Olympic Committee's president, Jacques Rogge, and his desire to show the Games' feminine side, could roller derby's time be coming?
Something which began in Depression-era America as a mixed sport but is now generally played only by women in 135 US leagues is gaining popularity across Europe, with teams in a dozen British towns and cities.
So why become a rollergirl? Stephanie Ross, aka CorrectionalFelicity, from Preston explains: "There's not much else a 27-year-old can do when you want to take up a sport. And as it's girls-only sport you don't get guys doing it who are better than you. It's a full-on game. You hit people really hard and get a lot of aggression out of your system. Basically you hit them with your full body, but you can't hit their heads or their back or below the knee. You go for the shoulder or the chest. It's a real adrenalin booster. You hit each other and then you go for a drink afterwards, a bit like rugby I suppose."
TJ Usher (Dot Slash), 29, a former figure skater, took it up after seeing a documentary in the US. "I find it physically challenging, a good way to keep fit and make new friends. You get rid of aggression in a controlled environment. I don't like gyms, I find them boring, and there are no other sports that interest me. Fitness is the main thing, I reckon you can burn off about 500 calories an hour, which for a woman is a good thing. It means you can eat as many cakes as you want afterwards. As a sport, it's cool."
Not all rollergirls are Amazons. Some are mere slips of things, such as Jess Holland (Sky Rockit), a 24-year-old London journalist. "I played roller hockey at university and read about London Rollergirls in Time Out 18 months ago. I like the fact that it's all girls and that you can dress up a bit and have a different persona. It suits all shapes and sizes and you don't get your usual sporty types doing it.
"There used to be one or two men's teams years ago, but now it is all women. It's not just a feminist thing, but I think it is a way of women becoming more assertive."
Although men are not allowed to skate, they can pitch in as referees, masseurs and medics – bruises are the norm and broken bones not unknown.
"This is something we take seriously as a sport," says Jayne Mahoney (Fox Sake), whose husband, Dave, is the London announcer. "And when you've had a bad day there's nothing like putting your skates on and knocking the crap out of someone else."
Jam and dodgers
Game on: Roller Derby involves two teams of five players (four blockers and a jammer) skating anti-clockwise round a small, narrow indoor track. The jammers try to break ahead of the pack by fighting their way through, gaining a point for each opposing player they pass or push out of bounds. The opposing blockers try to stop them.
Duration: A "bout" lasts one hour, comprising either two sessions of 30 minutes or three of 20 minutes, with teams switching lanes and restarting after each two-minute "jam".
Legal: Body-checking, hip and shoulder barging and, in some leagues, elbowing.
Illegal: Tripping, punching and headbutting.