David Cameron has demanded Google do more to rid the internet of child pornography, warning that lives are being put at risk.

The Prime Minister said he was "sickened" by the material available online and told web search firms to stop making excuses.

The companies have been summoned to a council of war with Culture Secretary Maria Miller and Cameron's adviser on the issue, Tory MP Claire Perry, on June 17.

Research by the Child Exploitation and Online Protection Centre (CEOP) has suggested that more than half of those who view child abuse images go on to commit abuse themselves.

Mark Bridger, who was convicted last month of the murder of five-year-old April Jones, was found to have a cache of 65 criminal abuse images.

Cameron said: "I am sickened by the proliferation of child pornography. It pollutes the internet, twists minds and is quite simply a danger to children.

"Internet companies and search engines make their living by trawling and categorising the web.

"So I call on them to use their extraordinary technical abilities to do more to root out these disgusting images.

"That is why the government I lead is convening a round-table of the major internet companies, and demanding that more is done.

"There are encouraging signs that the industry is willing to step up, increasing funding and technical support for organisations combating child sexual abuse imagery online. But I want more action.

"The time for excuses and blame is over - we must all work together. The safety of our children is at stake - and nothing matters more than that."