Boohoo has breached the advertising code by sending an email advert headed “send nudes.”
The fashion brand put the phrase in a message sent to promote a range of clothes coloured to resemble skin.
It pictured a female model wearing a short, white dress and beige jacket with the words “Send nudes. Set the tone with new season hues” written across the image.
Boohoo.com said their ad used the word “nude” solely to describe the clothing colours that were similar to people’s skin tones.
But though the Advertising Standards Agency (ASA) acknowledged this meaning of the word, they concluded the phrase “send nudes” was likely to be understood as referring to requests for sexual photos, which could be a form of sexual harassment.
ASA therefore deemed the email breached their code and was “socially irresponsible” because it made light of a “potentially harmful social trend.”
The UK’s advertising regulator was particularly concerned that Boohoo targets “relatively young” consumers aged between 16 to 24 years old.
They said youngsters were more likely to be “harmfully affected” by pressure to share sexual images of themselves.
ASA added: “Furthermore, in the subject heading of an email, without any further context, the phrase “send nudes” was likely to be disconcerting for some recipients, particularly those who might have personal experience of being asked to ‘send nudes’.”
The firm has been told not to publish the same ad and to ensure other marketing was socially responsible.
Yahoo UK has contacted Boohoo for comment but the brand told BBC: "We note the ASA's ruling and recognise our obligations to ensure that advertising is socially responsible."
In a separate ruling, the ASA banned a video advert for clothing company Missguided, broadcast back in June, during ‘Love Island’, which it claims "objectified women".
The ad promoted the retailer’s swimwear line and included models in bikinis and other swimwear.
But the ASA received a complaint that the ad “overly sexualised and objectified women”, so decided to investigate.
Missguided said the advert served to promote a "particular lifestyle" rather than just clothing and the "display of skin was relevant, necessary and unavoidable" given the ad was for beach-wear.
The ASA disagreed and said the images were "highly sexualised" and some of the women depicted in the poses were not wearing the clothes Missguided said it was promoting.
The ad was likely to cause "serious offence" to some people, it said.
Missguided has been told not to run the ad again and must guard against creating similar content that "objectifies women".