Internet firms are meeting ministers amid calls for more to be done to block images of child sex abuse and to stop children viewing pornography.
Last week saw the formal launch of the National Child Sexual Abuse Review Panel as agreed by the Association of Chief Police Officers and the Crown Prosecution Service, and Prime Minister David Cameron has called for more to be done to remove illegal material from the web.
Web firms have so far rejected calls to impose parental filters as a default setting but 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.
Offenders who sought child porn online
Internet service providers in the UK have been at the centre of the debate about online images showing the sexual abuse of children following recent high-profile court cases in which offenders were known to have sought child pornography online.
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.
Ahead of today's [18 June] meeting, at Westminster Culture Secretary Maria Miller said: "Child abuse images are horrific and widespread public concern has made it clear that the industry must take action. Enough is enough.
"In recent days we have seen these companies rush to do more because of the pressure of an impending summit. Imagine how much more can be done if they seriously turn their minds to tackling the issue. Pressure will be unrelenting."
Collaboration to improve image blocking tools
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.
Under the current system, the site is blocked, but internet users only see an "Error 404" message.
Earlier this week, internet search firm Google said it would be helping to 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.