Adverts promoting an unhealthy or unrealistic body image among Londoners are to be banned from the Tube and bus network from July. Mayor Sadiq Khan said the measures would send the advertising industry a clear message about ads which make people, particularly women and adolescents, "ashamed of their bodies".
The new policy, which was part of Khan's election pledge, is expected to affect only a handful of the 12,000 ads which target Londoners on the Transport for London (TfL) network every year.
It would still allow posters featuring men and women dressed only in their underwear, but it means controversial campaigns like Protein World's "Are you beach body ready?" would unlikely be allowed in the future.
The weight-loss posters, which featured a slim model in a bikini, provoked a backlash among many Londoners who felt it encouraged women to be unhappy with their body and pressured them to be dangerously thin.
Despite a petition against the advert attracting more than 70,000 signatures, the posters were not banned by the Advertising Standards Authority regulator, who said the campaign was not in breach of its code.
Khan said of the new policy: "As the father of two teenage girls, I am extremely concerned about this kind of advertising which can demean people, particularly women, and make them ashamed of their bodies. It is high time it came to an end.
"Nobody should feel pressurised, while they travel on the Tube or bus, into unrealistic expectations surrounding their bodies and I want to send a clear message to the advertising industry about this."
TfL said it did not expect the policy to have an impact on its advertising income, which is expected to reach £1.5bn ($2.1bn, €1.9bn) over the next eight years.
The Mayor has also asked TfL and advertising partners Exterion Media and JCDecaux to establish a steering group to monitor and keep its policy under regular review.
Graeme Craig, TfL Commercial Development Director, said: "Advertising on our network is unlike TV, online and print media. Our customers cannot simply switch off or turn a page if an advertisement offends or upsets them and we have a duty to ensure the copy we carry reflects that unique environment. We want to encourage great advertising that engages people and enhances the transport network."