The chief executive of the UK Advertising Standards Authority has issued a plea to advertisers to avoid using “irresponsible” images of unhealthily thin-looking models.

Guy Parker, CEO of the UK watchdog, said adverts where models appeared to present an unhealthy body image were “becoming more of an issue” and called upon advertisers to “please, please, please think very carefully” about the body types they depicted.

Recently, the regulator banned adverts from high street retailers including M&S, Next and Zara for presenting “irresponsible” images of models who appeared “unhealthily thin”.

The regulator reported that in one of the images used by M&S in April, a model “wore large pointed shoes which emphasised the slenderness of her legs”. A downwards tilting camera angle made the model’s head appear “out of proportion with the rest of her body and further highlighted her small frame”.

In response, M&S said it “took concerns about the depiction of body image in [its] ads very seriously”. The shoes had “only been chosen for stylistic and fashion purposes” while the camera angle “had not been chosen to exaggerate the model’s proportions”.

The watchdog typically receives five or six complaints a week about such ads, but after the ruling against M&S in July that increased to more than 20. In 2024, it received a total of 61 complaints about the size of models in adverts. According to the ASA, 45% of the UK public are concerned about ads that include idealised body images of women.

Parker, who has worked for the ASA for more than 30 years, said a wider “return to thinness in fashion” was causing an increase in complaints. “It is not unprecedented,” he said. “Fashion trends go in cycles. In the 90s we had a ‘heroin chic’ period and we banned several ads back then. Our rules have long required ads to be socially responsible. It may be that we’re kind of back in that sort of space today.”

The rise of weight-loss medication may also be affecting the types of bodies being portrayed in ads. “There is a connection between the two,” said Parker, who is overseeing a project focusing on injectable versions. “There have been too many cases of advertisers, many of whom should know better, promoting prescription-only weight-loss medicines to the public. That is against the law and our codes.”

The watchdog has previously been accused of double standards for allowing campaigns starring plus-size models, with some online critics calling such models obese. Parker said a wider cultural context played a part here. “We know in the UK currently, society tends to view thinness as aspirational. That’s not the same case when it comes to being overweight.”

Parker said it was important not to “demonise the models that have been featured in ads”. The rulings are generally not about the model’s body but about how advertisers may have manipulated images of a model. Lighting, makeup and the type of poses used all play a role.

Parker said the final images selected for use was crucial, pointing to a recent ruling against Zara as an example of this. In four adverts, starring two models, the ASA found that shadows used over one of the model’s legs made them “appear noticeably thin”, while the low-cut design of a shirt worn by the other model created “a focal point around her collarbone, which was protruding”. Two other adverts starring the same models did not breach its code.

Responding to the ruling, Zara said during its hiring process both models had provided medical certificates proving they were in good health.

Parker said: “The key moment is when you are selecting the images because there will probably be a whole bunch of images of the model you can use but there might be some that you shouldn’t. It comes down to these advertisers making sure that they have got a stage in their compliance process that actively and consciously checks to make sure irresponsible images don’t slip through.”

Noticeable bones are especially contentious. “We have had issues where ribs are really visible. Sometimes it is very thin-looking arms or thin-looking legs. I say thin-looking rather than thin because it is about how models are presented in clothes, not the model per se.”

Parker said “thin” was subjective. “I don’t think any of these advertisers are intentionally promoting this sort of concept of unhealthy thinness. But that can sometimes be the result if they are not really careful about the images they select to use.”