No 10 summit to tackle web porn and images of child abuse 18 June 2013 Last updated at 00:59 Internet firms are to meet ministers at No 10 amid calls for more to be done to block images of child sex abuse and to stop children viewing pornography. Prime Minister David Cameron has said more can be done to remove illegal material from the web and steer children away from legal adult content. Labour says voluntary controls are not working and parental authority has been undermined by technological change. Web firms have rejected calls to impose parental filters as a default setting. Real threats Internet service providers in the UK have been at the centre of the debate about online images showing the sexual abuse of children following two high-profile court cases in which offenders were known to have sought child pornography online. Mark Bridger, sentenced to life in May for the murder of five-year-old April Jones in Machynlleth, Powys, searched for child abuse and rape images. And police who searched the Croydon home of Stuart Hazell, jailed for life in May for murdering 12-year-old Tia Sharp, said they had found "extensive" pornography featuring young girls. The prime minister has pledged to "put the heat on" companies to make removing obscene material and blocking access to indecent images more of a priority, saying he is not "satisfied" enough is being done. Tuesday's meeting in Downing Street, to be chaired by Culture Secretary Maria Miller, will be attended by Yahoo!, Google, Microsoft, Twitter, Facebook, BT, Sky, Virgin Media, TalkTalk, Vodafone, O2, EE and Three. Claire Perry, the Conservative MP who advises the prime minister on the issue, said violent online images were still accessible even though they were outlawed and there was a link between them and horrific crimes committed against children. "If I have to sit with parents who've had their children taken from them whilst images, the most appalling images, of abuse are then found on those gentlemen's computers, we can't sit by and do nothing about that," she told Channel 5. Ministers say they also want to make it easier for parents to ensure their children are not exposed to unsuitable material online. A 2011 review by Mothers Union chief executive Reg Bailey concluded that children were being bombarded by sexual images on the internet, television, music videos and in advertising and it should be much easier for parents to block under-age access online. Education The body that represents the UK's net suppliers has said filtering tools should be more widely available but it opposes default settings. The Internet Service Providers Association argues they can be "circumvented" and that education and empowering parents to make safe choices must go hand in hand with technological solutions. It says it will use the meeting to stress what the industry is already doing to block access to images of child abuse and criminally obscene adult material and to remove them in conjunction with the police. Mrs Perry said progress was being made on a voluntary basis to ensure adult material could not accessed online in a public place and age verification mechanisms and "one click" filters in place unless parents turned them off were becoming widely available. "We've done it without regulation; we've done it by working systematically with the industry," she said. At the moment the filtering work is going really well, and no need for legislation. The BBC's technology correspondent Rory Cellan-Jones said the internet industry was angry that what it saw as separate issues - illegal child abuse images and children's access to harmful material - were being conflated. BT said recently that any of its customers attempting to access web pages on the Internet Watch Foundation's list of identified images of child sexual abuse would now see a message telling them that the site was blocked and the reason why. In a related development, internet search firm Google has said it will help create a database of images to improve collaboration between the police, companies and anti-abuse charities as well as fund developers to improve better tools to block images.