Advertising regulators told Urban Outfitters Europe to pull an online underwear ad from its United Kingdom site that featured a skinny model, saying her “inner thigh gap” promoted an image that was “irresponsible and harmful.”

Britain’s Advertising Standards Authority received a complaint about the photo, which was advertising a pair of polka-dot bikini briefs, according to reports. The complaint claimed the model, who was pictured from the waist down, was “unhealthily thin,” according to the agency’s ruling.

The agency agreed and ordered Urban Outfitters to remove it.

Urban Outfitters’ online underwear section shows small shots of models from their waists to their thighs. Many images show a gap between the thighs, but one photo in particular created a controversy.

“The [Advertising Standards Authority] considered that the model was very thin, and noted, in particular, that there was a significant gap between the model’s thighs, and that her thighs and knees were a similar width,” the agency stated in its adjudication. “We considered that the model looked underweight in the picture. We understood that Urban Outfitters’ target market was young people and considered that using a noticeably underweight model was likely to impress upon that audience that the image was representative of the people who might wear Urban Outfitters’ clothing, and as being something to aspire to. We therefore concluded that the ad was irresponsible.”

Urban Outfitters in Britain and United States could not be immediately reached for comment.

The authority has the power to order an ad withdrawn if it judges it to be in “breach of the U.K. advertising code,” in this case, a provision mandating “responsible advertising.”

“Inner thigh gap” has become a trend with women and girls who believe that having a space between their inner thighs while standing is considered ideal.

Urban Outfitters said although the model was thin, it did not think she was underweight.

“They added that it was common practice to use slim models in the underwear industry, but they did not consider that the model was underweight or unhealthily thin; they considered she had a naturally tall and slim physique,” the company told the agency in its response.

People are weighing in on both sides of the debate.

Nikki French, a model for BMG, said showing a skinny model in a clothing ad should come as no surprise.

“That’s the way our society is. We promote those skinny models,” she told Fox News. “The majority of models are really thin and the agents will only take you if you are a specific size. It’s the way it’s been ingrained in the fashion industry.”

Indeed, Urban Outfitters uses a number of thin models in its online ads both on its U.K. and U.S. sites.

But Lynn Grefe, president of the National Eating Disorders Association in the United States, told USA Today it’s not “normal” to encourage such unattainable body shapes.

“People come in different shapes and sizes,” she said. “These images fuel the fire of eating disorders and poor self body image and advertisers should have to take more responsibility.”