Clothes Show Live is one of the prime events for spotting new models. Luke Blackall reports

You could be forgiven for thinking that the 150,000 girls (and a few parents and boyfriends) who will visit Birmingham's NEC for the Clothes Show Live this week were there for the fashion.

While once they might have come for the miles of stands dedicated to clothes and beauty products, increasingly they flock to to the Midlands to follow their dream of being plucked from obscurity to the catwalk.

"A lot of visitors of a certain age come because they want to be spotted," says Gavin Brown, managing director of Clothes Show Live.

"This has become the UK's premier event for scouting, some come hoping to be discovered as the next Cat Deeley or Vernon Kay, both of whom were spotted here."

The firm that spotted those models-turned-stalwarts-of-Saturday-night-telly, Select Models, has been the official agency of the event for the past 15 years and have become an increasingly important part of the event. Two years ago, providing evidence that dreams can come true, they found Nina Porter, a schoolgirl from North London, who has since become the face of Burberry.

The Clothes Show Live started in 1989, as a spin-off from the now defunct TV programme presented by Jeff Banks and since then has welcomed an estimated 3.5 million fashion lovers through the doors and into the vast NEC in Birmingham.

In the new age of reality TV, fast fashion and spiralling ambitions among young people, it provides an outlet for those who want not only to have their unfulfilled talents discovered – but also their faces noticed.

At the Select stand on Sunday afternoon, a growing group of wannabes, showing nerves in varying degrees, hovers around the stand. One girl walks slowly back and forth, pausing each time she passes as though she is looking for something.

After her third, solitary catwalk, she wanders off. Minutes later an eager mother approaches with her rosy-cheeked daughter, keen that her her beauty be recognised. Both are (politely) sent away.

Throughout the day the agency organises shows with some of the models on their books and presentations from staff on a small stage in the main room. After the live show, things get worse, with at least a hundred girls converging at the stand.

Soon weary staff use a megaphone to disperse the crowd, reminding them they have to be approached, rather than approach the stand to make it as a model. Of course most girls will walk away disappointed. The agency is aware that the fashion industry has an arguably unfair reputation as cold and exclusive – and does what it can to let down girls gently. "The ones that want to be spotted gravitate towards the stand," says Susannah Hooker Head of New Faces at Select. "Some come year after year, hoping to be spotted, even though they never will. You have to be extremely tactful. At the end of the day, these are young girls."

The company's scouts patrol the floor of the venue from 9am to 6.30pm every day of the show. Girls that are seen to have potential are approached, given a card and asked, if interested, to visit the stall. There, they are photographed and have their height measured (you have to be or have the potential to be 5'9") and fill in a form with their and, if under 18, their parents' details.

"They might be sitting on the floor with friends; they might be in the queue for the toilet," says Hooker.

"If they're coming out of the fashion theatre you can have 4,000 girls streaming towards you and you might just have a split second there and then to decide whether they are right."

Testing to see whether I have what it takes to make it as a scout, I point out a tall, bright-eyed, blonde girl, who, to my untrained eye at least, looks a bit like a young Rosie Huntingdon-Whiteley.

Susannah is only half-impressed. "She might be scouted by someone else, but we're looking to innovate and find new looks," she says. "It's very rare that we go for the classic prettiest-girl-in-school type.

"A lot of our new faces have quirky, different looks. In fact a lot of models have been bullied at school for being different looking."

At 4pm each day Select puts on a catwalk show with 10 of the prospective models they have spotted in the crowd that day. Some step nervously along the runway; others give away the tell-tale signs of having practised in their bedrooms.

What's striking is just how young they seem. One twelve-year-old (who is keen to add she's "going on thirteen") comes off the stage. She had been spotted performing with her dance group and approached by a scout. "I've always wanted to be a model," she says, confidently. "And my parents have always wanted me to be one as well."

Like many agencies now, Select is strict about how it manages the youngest recruits.

"Although we do start working with some at 12 or 13, most of them won't work until they're older," she says. "We like to keep an eye on them; meet them and their parents every six months or so and take their picture again."

Also here is Rosie Tapner, 15, who looks like she's enjoying herself as she gets the biggest cheer of the afternoon.

Rosie's part of a 400-strong group from Downe House school near Newbury in Berkshire, which describes itself as "one of the country's leading boarding schools" and has organised a school trip to the event.

And it's clear to see that for some the possibility of being thrust from normality to what is seen as the glamorous world of fashion is a thrill.

Rebecca Porter, 17, from Leicester was spotted after coming to the show with her parents Julie and Andy. The family seem nice, normal – a world away from the the pushy-parent stereotype – and seem genuinely surprised to be approached.

"She just came to get a signed book from Gok Wan," she says.

"Obviously we have always thought she was very pretty, but we'd never thought about modelling, but it's made her day."

Clothes Show discoveries

Vernon Kay Worked as a council "hygiene operative" when scouted. Now a successful ITV presenter

Erin O'Connor Spotted during a day out with her school. Now a supermodel worth £12m

Nina Porter Spotted in 2008. Still at school, and also appears in the latest Burberry campaign and has featured in Vogue

Cat Deeley Discovered despite "the most hellish nightmare perm". Now a TV presenter on both sides of the Atlantic