Children's charity Barnardo's says youngsters are being sold for sex on the internet and then rated out of ten by paedophiles.
Some youngsters have been sold by relatives and friends who advertise them online with indecent photographs taken in their own homes.
Pre-pubescent boys and girls are also being lured into taking part in live sex shows screened on the web which dozens of perverts pay to watch.
In a shocking report, Barnardo's has also warned new GPRS and 3G mobile phone technology could lead to many more children being abused through the internet.
The report said: "It will increase opportunities for young people to communicate and access websites and other internet services away from the supervision of their carers. This adds another dimension to the degree and nature of the risks to children."
In a survey of children it has already dealt with, Barnardo's identified 83 who had been sexually abused through the internet and mobile phones. Of those seven were sold online to paedophiles and one was abused live on the web.
The report said: "Over the last 18 months we have become aware that children are being advertised or sold for sex via chatrooms and bulletin boards on the internet. Not only are children being pimped in this way but these internet sites also inform the enquirer of 'how good a purchase' the child is by rating them from one to ten."
Message boards allow paedophiles to list where children for sale can be found, along with a description or photograph of the child, what sex acts they perform and how much a pimp charges, the report said.
Barnardo's identified one 14-year-old girl whose picture was placed on such a website by an older man who groomed her for prostitution. "She knew nothing about the site or the fact her photograph had appeared on it but because of the site she could be easily identified by other sex offenders," the report said.
PA