London (CNN) -- The girls strutting down the runway in The Savoy Hotel share many features - all are long-limbed, fine-boned and have glowing complexions. A silent army marching to the heavy music, past the front row A-listers peering out from behind their dark glasses.
But one girl is different: the only one with black skin in a battalion of white faces. Nadja is one of the few black models lucky enough to make this year's cut for London Fashion Week.
The lack of racial diversity in the fashion industry is a serious issue that needs to be tackled, according to supermodels Naomi Campbell and Iman, who this month launched a campaign to raise awareness of racism in the industry.
"The absence of people of color on the runways and photography reinforces to our young girls that they're not beautiful enough, that they're not acceptable enough," said Iman, model and wife of David Bowie, to CNN.
"The diversity that we live in, the world that we live in, is not what is shown on the runway. That to me is the concern. It's a bigger issue at large than just about runway and models."
Campbell and Iman, in a campaign spearheaded by former model agent Bethann Hardison, have written to the major fashion councils of New York, London, Milan and Paris calling for an end to racism.
The "Diversity Coalition," as the trio has named itself, identifies the fashion houses which "consistently use one or no models of color" in their runway shows - including Marc Jacobs, Victoria Beckham, Calvin Klein, Donna Karan and Rodarte. "No matter the intention," their letter says, "the result is racism."
CNN reached out to each of those companies for comment, but has received no response.
Runways getting whiter
Campbell says the situation for black models has become worse - not better - since her debut.
"When I started modeling in '86 there was Asians, blacks, whites, Indians, Chinese. It was very diverse," Campbell told CNN. "It's not like that today. It's heart-breaking to me that we're in 2013 and we're sitting here talking about this. But it has to be done and people need to know."
The numbers speak for themselves.
At New York Fashion week in February, only 6% of designs were shown on black models, according to statistics compiled by blog Jezebel. The vast majority of runway spots (82.7%) went to white models, with a growing proportion of Asian girls (9.1%).
In London, renowned model agent Carole White, who managed Campbell's career for 17 years, says designers here also tend towards white models for their shows.
"I think clients have this perception that black girls do not sell products, which goes way back to the 50's. I think it's engrained in every magazine editor. There are more products for blonde and blue-eyed girls. Everything is geared to that."
White has only 13 black models on her books, out of the 300 or so girls she manages. She says the bar is set much higher for black models and they have to be flawless to get booked, so she cannot afford to take them on.
"We're more discerning about the type of black girl we take, because we know they have to be stunningly beautiful, have an incredible body. "
"They have to be actually perfect" she says, whereas white girls, can be more quirky-looking.
Back at The Savoy Hotel, Nadja is walking for Temperley London as one of only three non-white models in the cast. She feels lucky to get work, but says it's harder for black models compared to their white peers.
"When I come to a show the hairdressers are not really ready for a black girl, for black hair. The makeup artists, they don't know how to do black skin. I can feel it sometimes - to be a black girl it's a bit tougher than for a white girl or a European girl."
Nadja says she sometimes feels like the token black girl in a show.
"I would love to be booked for shows ... because I am me - for my personality, for the person, for the model I am and not because I will be the only black girl for the show."
This tokenistic attitude towards diversity is something Campbell, Iman and Hardison are trying to tackle. But designers complain that they don't have enough good black models to choose from.
"There are not enough models coming to castings that are black," designer Alice Temperley told CNN. "That's basically not having the choice."
Iman also criticizes casting directors and stylists for their part in providing too few black models to designers. She says it's an attitude that has to change.
"I don't want to ever hear again a young model telling me that [casting directors] have said to her: 'We are not seeing black models this season.' To me that's offensive. To me that's a racist remark."
The Diversity Coalition hopes that by getting the conversation started and raising awareness of the lack of black models, they will force out discrimination from all corners of the industry.
Campbell says they'll keep speaking out until they see real change that lasts from season to season.
"We don't want this to be a trend. We want this to last."
In this famously fickle industry, these three women have a fight on their hands.