Experts agree that paedophilia on the Net is on the increase as the police launch their biggest crackdown yet on Internet child pornography in the UK. On Thursday 27 addresses across the UK were raided following six months' investigation by the Greater Manchester Police's Obscene Publications Unit. A 43-year-old man from Watford, an 18-year-old man from Wales and a 33-year-old man from West Yorkshire were among those arrested as a result of the raid, which has been dubbed Operation Queensland. Last year Operation Cathedral resulted in seven arrests in the UK and the seizure of around 100,000 illegal images. Child porn on the Net has been back in the news since ex-pop star Gary Glitter was jailed for four months for downloading obscene images on to his PC. In the US, ex-Infoseek executive Patrick Naughton is currently on trial for allegedly arranging to have sex with an under-age girl on the Net. Inspector Terry Jones -- who heads up Manchester's obscene publications unit -- has seen a massive increase in the number of computer images of children in circulation; around 30,000 have been seized this year compared to just a dozen four year's ago. He agrees that the Net has revolutionised the trade in child porn. "It has never been there in such numbers as it is now," he said. Ruth Dixon, assistant chief executive of the Internet Watch Foundation (IWF) -- the organisation which monitors child porn on the Net -- has also seen an increase. Last year the IWF referred 13,000 cases to police. Dixon expects this to rise to around 25,000 this year. She is concerned that newsgroups -- in which child porn is most prevalent -- are creating a Net army of paedophiles. "There appears to be groups of people who post regularly and they have developed their own sort of social hierarchy," she said. "They want to build up their collection and rely on the exchange culture," she said. Max Taylor, professor of applied psychology at the University of Cork believes between one and three new children are being abused every month to provide images for Internet paedophiles and while it is difficult to say how big the rings are, Taylor suspects vast numbers are involved as the Net make it easier to anonymously access illegal images . "The Internet facilitates the distribution of child and makes paedophile rings more effective," he said. He agrees with Dixon that a distinct community of paedophiles is emerging on the Net. He is convinced that membership of a paedophile ring increases the possibility of child abuse. "Status in the group relates to the number of images you have and whether you can provide fresh images," he said. New Net pictures of children being abused show a disturbingly domestic element according to Taylor. "Old images were often filmed in hotels or studios but the newer ones have a domestic quality. You will often see toys lying around," he said. Inspector Jones is in no doubt about the link between Net porn and child abuse. "Why would someone want a picture of a child of four being raped unless they had a very unhealthy interest in children. It disturbs me as a police officer, as a person and as a father," he said. Take me to the Web of Porn special. What do you think? Tell the Mailroom. And read what others have said.