The UK's four largest ISPs - BT, Sky, TalkTalk and Virgin Media - have announced that they will commit an additional £1 million collectively over the next four years to further crack down on the creation and distribution of child porn.

The level of additional funding is, however, likely to cause anger among campaigners and the wider public.

The money will go to the Internet Watch Foundation (IWF), which will intensify its work with the Child Exploitation and Online Protection Centre (CEOP) to seek out illegal images of child abuse before they are widely distributed online.

This is a fundamental change in the way that child sexual abuse content will be tackled, according to the Department for Culture, Media and Sport, because the IWF will no longer have to wait for illegal material to be reported before it can take action.

"The abuse of children is absolutely abhorrent - and that child is further violated every single time an image is circulated and viewed," said Secretary of State for Culture, Media and Sport, Maria Miller

"The IWF and CEOP already do important and valuable work. This agreement will mean these organisations will no longer be limited to reacting to reports received. They will now have the remit and the resources to take the fight to the criminals perpetrating these vile acts."

It is estimated that there are one million unique images of child abuse online, yet only 40,000 reports are made to the IWF each year. The ISPs said the new funding will supplement their existing "zero tolerance" approach to child abuse material online.

"The companies will work together with government, IWF and CEOP to establish how best these funds can be spent to tackle the availability of online child abuse content," they said in a joint statement.