Internet portal Yahoo! has changed its UK Instant Messenger client to block access to adult chatrooms based in the US. Anyone downloading a UK version of the software from Monday will not be able to access these rooms. The US version of the software, which anyone can access, will remain unchanged and users will still be able to get on to adult chatrooms based in the UK A Yahoo! UK spokesman said the firm has made the changes to its service in order to comply with UK law. He says that the decision was taken after consultation with children's charities and Internet watchdogs including ChildNet and the Internet Watch Foundation (IWF). ZDNet News has campaigned against the way in which Yahoo's IM chat facility operates since October. The use of the Internet by paedophiles is a growing problem. Members of the world's largest organised Internet child porn ring, dubbed the Wonderland Club, were convicted in the UK last month and are due to be sentenced this week. One of the convicted men, interviewed on Panorama this Sunday, praised the Internet for creating a community for people interested in child pornography. The club traded thousands of images of babies and children being subjected to sexual abuse in Internet newsgroups. Yahoo! reveals a number of initiatives designed to stop illegal activity. These follow publicity surrounding recent Internet paedophile investigations in the UK. In addition to stopping the UK Instant Messenger client from reaching adult chatrooms, Yahoo! says it will no longer be possible to search the US-based adult section of Yahoo! Clubs from the UK. This service allows users to create meeting places for those with similar interests. Yahoo! UK also reiterates its plans to appoint a social policy specialist to review the safety of its services and users will be encourage to report potentially illegal activity, says a spokesman. Yahoo! Instant Messenger chat service, which allows individuals around the world to communicate freely using a user name, has in the past been linked with Internet paedophiles. Patrick Green was convicted in October 2000 of raping a girl he met through Yahoo!'s IM service. "Yahoo! is committed to tackling the problem of individuals using our site to harm minors in any way," says a spokesman for Yahoo! UK. However Yahoo! believes that it is wrong to single out the Internet as a vehicle for paedophiles. "The issues that the Internet industry is facing are the same as those that society is facing today," says the spokesman. ZDNet UK downloaded the client Monday from the UK Web site and was unable to access any chatrooms. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet News Forum. Let the editors know what you think in the Mailroom. And read what others have said.