Six o'clock on a Sunday evening is not the usual time to see people pouring out of a nightclub in Camden, north London. But this is no ordinary gig and these are not ordinary clubbers.
Subverse at Underworld caters for under-18s. Music fans flock there on the first Sunday of every month without the fear that they will be turned away because of the age restrictions that operate at the venue's other gigs.
Julie Weir, managing director of the music label Visible Noise, founded Subverse - the first UK all-ages gig - six years ago. She got the idea when one of her bands played at a gig open to adults only.
"We'd told kids in advance that they wouldn't be able to come in," she says. "But one hadn't seen the notice and came all the way down from Newcastle. That's a hell of a way to come to see nothing."
But the issue is more than one of disappointed fans. "These are record buyers," says Weir. "It seemed ridiculous that venue restrictions should stop a huge number of the band's supporters from seeing them. Not all kids want to go to a Steps concert at Wembley Arena with their mum."
And so, Subverse was born in Camden. Starting at 2pm, anyone of any age can attend four hours of alcohol-free performances.
"Licensing laws are the issue," says Weir. "Most venues impose over-18 restrictions for fear of losing their liquor licence if they serve underage kids."
A couple of venues have piloted lowering the age to 16 and giving wristbands to those who cannot be served, but had problems with over-18s supplying younger gig-goers. So, under-18 nights have gone from strength to strength. In London, Camden's Subverse is targeted at rockers while, in south London, Underage Club caters for indie music followers.
In Birmingham, Teenculture has just relocated to a larger venue, the Sanctuary, in response to demand. In Wolverhampton, Generation is a growing monthly attraction, while Subverse opened in Wales last year. The events are about more than enjoying music. Many of the gigs are becoming interactive affairs, giving wannabe musicians the chance to meet their favourite artists and hone their own talents.
"There's been a big turnaround to kids getting on guitars rather than turntables," says Weir. "And a big part of what we do is allow kids to come down, meet their idols, and play along."
Neither are the kids being fobbed off with minor bands. Headlining groups such as the Automatic and the Fratellis realised that they need to play under-18 gigs to satisfy their fans. Record labels see them as a way of finding new signings.
This may help explain some of the very young British bands currently enjoying success. Visible Noise's Bring Me the Horizon includes band members under-18; Cajun Dance Party are young enough to be in school.
"The whole face of music is being revolutionised by young people on the internet," says Weir.
And, as demand in the live music industry has changed, so has supply. It is no longer clear who is running the show, according to industry insiders. At 14 years old, Underage Club's founder Sam Killcoyne is younger than most of his customers.
The enthusiasm shown by those on their way home from Camden's Subverse suggests this underage trend is set to continue.
"Any-age nights are great, but I'm even more up for gigs that are restricted to under-18s," said one female regular. "There are fewer disgusting older men."