An Yves Saint Laurent (YSL) advert has been banned after the advertising watchdog ruled the model used looked "unhealthily underweight".

The ad, which appeared in print in Elle magazine, featured a black and white photo of a women lying on the floor with her eyes closed.

The advert prompted complaints to the Advertising Standards Agency (ASA) over concerns the model in the photo appeared too thin and questions about whether it was irresponsible.

The ASA has now upheld the complaint and banned the advert. The watchdog said YSL "did not agree with the complainant's view that the model was unhealthily thin" but did not provide a detailed response.

A spokesperson said: "The ASA considered that the model's pose and the particular lighting effect in the ad drew particular focus to the model's chest, where her rib cage was visible and appeared prominent, and to her legs, where her thighs and knees appeared a similar width, and which looked very thin, particularly in light of her positioning and the contrast between the narrowness of her legs and her platform shoes.

"We therefore considered that the model appeared unhealthily underweight in the image and concluded that the ad was irresponsible."

Elle has not responded to the complaint or the ASA ruling.

In December, the ASA also ruled high-street brand Urban Outfitters had released an "irresponsible" advert featuring a "very thin" model.

Earlier this year, a separate campaign for YSL perfume Black Opium was cleared by the ASA following complaints that it glamorised drug use.