Instead these wanna-be Lolitas are on their way to something called “School Disco,” a club night where patrons dress up in their button-downs and dance to the ’80s music of their youth. “It’s escapism without doing anything illegal,” says DJ and School Disco founder Bobby Sanchez. That nostalgia for school days has taken London by storm. Every weekend upwards of 7,000 partygoers pay $18 apiece to get into clubs that require them to dress in uniform. Next month School Disco is sponsoring an outdoor party in Clapham Common that is expected to draw 40,000 participants who are eager to run relay and three-legged races, eat lunches of boiled cabbage and unrecognizable meat, and listen to bands like ABC and the Human League. The group’s Web site, schooldisco.com, which helps people track down friends from high school, averages more than 1 million hits a day. Friends Reunited.com, which charges nearly $8 for the same service, has gone from around 5,000 registered members in early 2001 to more than 6 million today. Similar reunion Web sites have been springing up in Germany and France, with one French Web site receiving more than a million hits in the past six months.

High-school reunions have always been a popular concept in the United States (the American Web site Classmates.com claims to have 29 million users). But aside from those with an allegiance to their old boarding schools, the idea is relatively new in Britain. Nobody needed reunions in the past, when English graduates typically stayed within a few miles of home; the hunt for an old friend was often as easy as strolling down to the local pub. Now, says Dr. Marie-Claude Gervais, a lecturer in social psychology at the London School of Economics, “we are more dispersed than years ago, and we live more isolated, anonymous lives. Any means to reconstruct those [kinds of] networks will inevitably do well.”

Particularly for Londoners, many of whom have moved to the city from elsewhere, reunions both real and artificial bring a sense of structure to the often isolating experience of living in the big city. School is often the first time people experience a sense of collective identity, says Richard Scase, a lifestyle forecaster and author of “Britain in 2010.” “Things like school uniforms were a first attachment to a place or organization creating a temporary security, a sense of belonging to something bigger than you.” Those who are most eager to relive the past have often reached a point when they’re uncertain about the present. “In your early 30s, there is this questioning of, ‘Where am I going?’ It is a time of stocktaking and self-assessment,” says Scase. “School gives us a permanent peg to hold onto.”

A similar impulse led to the founding of both School Disco and FriendsReunited. Sanchez was fired for spinning ’80s tunes in a London dance club one evening in 1999. Driving by his old school on the way home, he took a literal stroll down memory lane. “I thought, ‘If I can relate to that [music], so could others’,” he says. Meanwhile, FriendsReunited founder Steve Pankhurst and his wife, on the eve of becoming first-time parents, began reminiscing about their own school days and old friends. They started tracing their peers via the Internet, and soon their pet project blossomed into a business that attracts 20,000 new members a day.

Beyond all the sociological explanations, though, a large part of the attraction of these groups and club nights remains simple fun. Many partygoers will cite the thrill of role-playing and theatricality when explaining why they love to dress up as teenagers. Says Gervais, at these parties and on these Web sites, “you can always stretch the truth,” allowing a type of freedom from the constraints of everyday life. Others admit to even simpler motives. “Why am I here? Pretty obvious, isn’t it?” says Joe, a 30-year-old IT exec, eying a blonde in a short pleated skirt that would never pass inspection from the headmaster. That urge, at least, hasn’t changed with the years.