More than 75% of internet users who have stumbled across pictures of online child sex abuse had no idea of where to report it, a new survey reveals

The poll for the Internet Watch Foundation, a charity that shuts down illegal content, found 77% of people were unaware that it ran a "hotline" for reporting abusive material.

"The UK has a very proactive approach to tackling child sexual abuse content online but we could do even more with the public's help," says IWF chief executive Peter Robbins.

"Internet consumers should know that if they do stumble across these images then it's vital to report them to the IWF."

People who report illegal content through the IWF website are protected by law, he says. Users of the site can also report anonymously, or leave their contact details should they wish to be informed of what's happening to the site they reported.

The IWF website received nearly 35,000 reports in 2007, but the organisation wants to raise awareness further and is rolling out an advertising campaign including banner adverts to educate people about the site.