Microsoft and Google tighten block on child abuse images Google and Microsoft have overhauled the way their search engines respond to queries for child sex abuse images, in response to mounting political and public pressure. Both companies, which already block known child abuse images, have introduced new technology to make it even less likely that illegal content appears in their search results. Google said it had substantially changed the way its algorithms responded to more than 100,000 search terms associated with child sexual abuse, and that for 13,000 terms it would display warning messages. "These measures will have a significant impact on our ability to tackle child abuse imagery online," said Susie Hargreaves, chief executive of the Internet Watch Foundation, which identifies images of abuse and reports them to internet companies so they can be blocked. The new technology will first be rolled out in the UK and then extended to other English-speaking countries and more than 150 other languages by the middle of next year. Eric Schmidt, Google's chief executive, wrote in the Daily Mail: "While no algorithm is perfect - and Google cannot prevent paedophiles adding new images to the web - these changes have cleaned up the results for over 100,000 queries that might be related to the sexual abuse of kids." Prime Minister David Cameron, who hosts a conference on child pornography at Downing Street on Monday, described the internet companies" move as "significant progress." Mr Cameron had threatened to introduce legislation if the internet companies had not acted; in June the government summoned 13 internet companies, including Google, Microsoft and BT, to demand they draw up specific plans to tackle online child abuse. The prime minister will also use the meeting to unveil details of an initiative between the UK's National Crime Agency and US law enforcement groups to tackle paedophiles and other criminals who use hidden networks, often known as the "dark web," to evade detection. Google and Microsoft, which runs the Bing search engine and powers Yahoo, have in recent months put more than 200 people to work developing new technology to tackle child abuse. Google insiders say that its search results have for years been almost entirely free of links to illegal child abuse content, thanks to existing measures it had put in place. They say the main visible effect of the change to its search results will be that links to legal pornography websites, which purported to show underage people, will be replaced by news sites and sites that provide counselling and advice.