The image showed a model with a significant gap between her thighs, posing in a pair of "polka dot mesh briefs".

According to the Daily Mail, the ASA imposed the ban after receiving a complaint from an unnamed source.

The ASA – which regulates misleading, harmful or offensive advertisements – said: "The complainant, who believed that the model in the picture was unhealthily thin, challenged whether the ad was irresponsible and harmful.

"We 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."

It added: "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."