Now it has emerged that one of the "administrators" of the page - users with the right to edit its content - is believed to be a British schoolboy linked to a network of hackers in Australia, Britain and America who have set up Facebook pages featuring offensive sexual and violent content. Micheal O'Brien, a Canadian computer systems engineer who co-founded the Rape Is No Joke (RINJ) campaign to pressure Facebook to delete "rape pages" via petitions and boycotts, has tracked the activity on several such pages and contacted participants online. He told London's The Sunday Telegraph that associates of 4chan, a loose-knit collection of international "cyber-anarchists" who champion absolute online freedom, including the right to share pornography, have founded and administer several of the pages. The RINJ's own website has been attacked by hackers and campaigners have been subjected to virulent online onslaughts since they started to draw attention to the 4chan connection last week. Pro-4chan images have also been posted to the "alleyway" page. Facebook protects the identity of those who set up and run pages but Mr O'Brien has identified several posters as likely page administrators, including college students in Australia and a teenage boy in Britain.

With nearly 210,000 people indicating that they "like" it, and many million of monthly visitors, the "alleyway" page is the most popular. Others include "Abducting, raping and violently murdering your friend as a joke", "Pinning your mate down while someone HIV positive rapes him for a laugh", "Police call it a restraining order, we call it playing hard to get" and "Turning into a chain smoking sexual predator when you drink". Many of the regular users who "post" on the pages are young Australians and Britons- many still at school, judging from information on their own Facebook profile pages. The website allows any child aged 13 or older to open an account. Activists and victims' support groups in Britain and America, where Facebook is based, have urged the social networking site to shut down and remove the pages. But despite an online petition signed by more than 200,000 people worldwide, the internet giant is refusing to do so. Facebook did not respond to repeated requests for comment by The Sunday Telegraph. But in response to previous complaints about the pages, the company has said that while they may express "outrageous or offensive" opinions, they do not violate its rules banning content that is hateful or incites violence. "It is very important to point out that what one person finds offensive, another can find entertaining," a spokesman said. "Just as telling a rude joke won't get you thrown out of your local pub, it won't get you thrown off Facebook."

An administrator of the "rape page" posted an online defence in response to the controversy, insisting that he did not support or promote rape but then directing a sarcastic barb at critics. "i d[o] not support rape this group doesn't," the person wrote, with a lack of grammar and in internet shorthand characteristic of many postings. "thanks for supporting us uve made us get even more likes i thank u for that but this group has not dne anything wrong according to the terms and cnditions f facebook groups s if it does get taken down it will result in court because it has done nothing wrong." Jane Osmond, co-editor of the Women's Views on News website, which has led the campaign in Britain, said: "It's ludicrous to compare the content on this page to pub humour. Rape is a crime and we live in a society where the threat of rape is in the mind of every woman who has walked down a street alone at night. Making a joke about rape is not just not funny. It allows people to dismiss it as something not serious. "Those who post in this way are certainly mostly teenage boys and young men saying inappropriate things, but we do believe that these sites have attracted sexual predators too. It is a dangerous group with some dangerous users." Activists who have gone online to make their case, and to publish images for a campaign promoting consensual rather than forced sexual activity, have been subjected to such a violent response that some have complained to the police.

Campaigners on both sides of the Atlantic have now switched their attention to businesses as they believe Facebook is inclined to allow the pages to continue because of the viewers and hence advertising revenue they bring in. "Facebook will only listen to money, so we are now targeting the advertisers who have appeared on their pages," said Miss Osmond. Major companies that advertise on Facebook were furious to discover that their advertisements were appearing on the "rape page" and demanded they be removed. They included Barclays, 02, John Lewis, Sony, BlackBerry, American Express, Groupon, Heinz, National Lottery, the White Company and PepsiCo. After complaints from several businesses to Facebook, the "alleyway" page was "whitelisted" last week, meaning that no adverts could be rotated on it. But advertisements continue to appear on other pages where the content was just as offensive. The Sunday Telegraph, London

Additional reporting by David Harrison in London.