SEXY billboards featuring nearly-nude models in raunchy poses have been banned under new rules to protect children.

The Wonderbra image of Eva Herzigova next to the slogan "Hello Boys" and Sophie Dahl lying naked on a rug for Yves Saint Laurent – the most complained-about ad in history – would be likely to have fallen foul of the rules.

The most revealing adverts will be banned altogether while others within 100 yards of schools or nurseries will have to be toned down.

The guidelines, laid down by the Advertising Standards Authority, will put underwear and perfume ads featuring David and Victoria Beckham under ­scrutiny.

The ASA's code has been sent to advertisers and agencies and is illustrated with sample images showing what is ­acceptable.

Bikini shots are OK regardless of where they are located, but sexually suggestive poses face tougher tests.

These include images of ­stockings and suspenders and pictures where the legs are parted. Hands placed on underwear or on the hips could also be too sexually explicit. And campaigns featuring fully-clothed couples in a "passionate clinch" may face a billboard ban. The ASA will shortly begin ruling on complaints which will establish its boundaries.

The ASA held a public consultation in Cardiff. Chairman Lord Smith said: "The strength of feeling about ads of a sexual nature was telling."

The changes follow recommendations made in May after a review by Reg Bailey, chief executive of Christian charity the Mothers' Union.

He said: "Companies are working together to change industry practices and create a more family friendly society."

The Government-backed report suggested measures to halt the sexualisation and commercialisation of children. The PM will this week hold a summit with firms as part of a campaign against the sexualisation of kids.