The United Kingdom's advertising regulator ruled that a model appearing in a Gucci ad was "unhealthily thin," and ordered the advertiser to remove a still photograph that appeared in an online video posted last December.

Based on a complaint, the Advertising Standards Authority (ASA) investigated the video, which appeared on The Times of London website in December 2015. Several models danced to a soundtrack in the beginning of the video, which ended with still photos of individual models. One of the images at issue featured a thin woman "leaning with her back to a wall…wearing a long dress which covered her body from the neck down to her mid-calves including her arms." The second image at issue depicted a thin model seated on a sofa, wearing a high-necked jacket and skirt that covered her down to her mid-thighs.

In response to the investigation, Gucci told the regulator that the ads were part of a video that portrayed a dance party, aimed at "an older, sophisticated audience," the target population of the Times readership. The advertiser also contended that "it was, to some extent, a subjective issue as to whether a model looked unhealthily thin" but that Gucci did not believe either of the models presented such an appearance.

Both models had "slim builds," Gucci argued, and nowhere in the ads were any of their bones visible. Lighting in the ad was warm "to ensure there were no hollows caused by shadows" and their clothing was not revealing, the advertiser said.

But the ASA found the ad violated Section 3.1 of the Committee of Advertising Practice's Code, which states: "Marketing communications must be prepared with a sense of responsibility to consumers and to society."

While the model seated on the sofa did not appear to be excessively slender or underweight, the model leaning against the wall had "quite slender" arms and torso, which "appeared to be out of proportion with her head and lower body," according to the regulator's decision. Her pose added to the problem by elongating her torso and accentuating her waist "so that it appeared very small," the ASA said.

"We also considered that her somber facial expression and dark make up, particularly around her eyes, made her face look gaunt," the regulator wrote. "For those reasons, we considered that the model leaning against the wall appeared to be unhealthily thin in the image, and therefore concluded that the ad was irresponsible."

The "ad must not appear again in its current form," the ASA ordered, instructing Gucci to ensure that the images in its advertising are "prepared responsibly."

To read the ASA's decision, click here.

Why it matters: The UK regulator's decision takes a stand in the ongoing debate over weight in the modeling industry. Some countries have enacted laws to ensure that models are not underweight or unhealthy out of concern for the images presented to young women. The ASA has waded into the debate before, having ruled against another high-fashion company last year after concluding that a print ad featured an "unhealthily underweight model" with thin legs and a visible rib cage.