The picture, which appeared on the retailer’s app, featured a female model wearing slim-fit trousers and a white top

An advert by Marks & Spencer (MKS.L) has been banned for showing an “irresponsible” image of a model who appeared “unhealthily thin”.

The picture, which appeared on the retailer’s app, featured a female model wearing slim-fit trousers and a white top. She faced the camera with one hand in her pocket and the other holding a bag.

In a ruling published today, the Advertising Standards Authority (ASA) said the model’s pose and choice of clothing meant the ad gave the impression she was unhealthily thin.

The watchdog said the model’s collarbones were “very prominent” and that she wore “large pointed shoes which emphasised the slenderness of her legs”.

It added: “In part due to the camera angle which appeared tilted downwards, the model’s head appeared out of proportion with the rest of her body and further highlighted her small frame.”The Advertising Standards Authority said the model’s collarbones were ‘very prominent’

The ASA said it received complaints about another three ads on M&S’s app and website that featured two female models wearing a pink polka dot dress.

However, the watchdog rejected these complaints after ruling that the model’s face in the images “did not look gaunt” and that “while thin… did not display any protruding bones”.

M&S said its women’s clothing range “represented a full spectrum of sizes, ranging from eight to 24”, though it acknowledged that the models in the ads were size eight and at the lower end of its sizing range.

The retailer said it took concerns about the depiction of body image in its adverts very seriously and that models were selected not only for professional suitability but also for their health and wellbeing.

M&S confirmed that it had removed the image after receiving complaints.

However, the ASA said the ad must not appear again in any form and told M&S to ensure the images in its campaigns were prepared responsibly and did not portray models that were too thin.

The ruling comes amid concerns that the fashion industry is returning to “super-skinny” models following the rise of the “body positivity” movement in the 2010s, which celebrated diverse body types.

Chioma Nnadi, Vogue’s fashion editor, last year warned the industry should be concerned after data revealed a “worrying return to using extremely thin models”.