Britain considers banning Internet pornography over 'corroding' influence on children

PM pledges automatic filtering of adult material to protect children, plus outlawing of violent porn and blocking of illegal image searches

Every household in Britain connected to the internet will be obliged to declare whether they want to maintain access to online pornography, David Cameron will announce on Monday.

In the most dramatic step by the government to crack down on the "corroding" influence of pornography on childhood, the prime minister will say that all internet users will be contacted by their service providers and given an "unavoidable choice" on whether to use filters.

The changes will be introduced by the end of next year. As a first step, customers who set up new broadband accounts or switch providers would have to actively disable the filters by the end of this year.

The moves will be announced by the prime minister in a speech to the NSPCC in which he will unveil a series of measures to reduce access to pornography with a particular focus on illegal child pornography. He will say:

• The possession of "extreme pornography", which includes scenes of simulated rape, is to be outlawed.

• The Child Exploitation and Online Protection Centre (CEOP) is to draw up a blacklist of "abhorrent" internet search terms to identify and prevent paedophiles searching for illegal material.

• All police forces will work with a single secure database of illegal images of children to help "close the net on paedophiles".

In a separate move, Twitter is to introduce a tagging system to prevent such images being posted on its service. There are now millions of pictures posted among the 2bn tweets every five days. The intention is to introduce the system, which uses a Microsoft-developed industry standard called PhotoDNA, this year if possible.

The prime minister's speech is designed to answer critics who accuse him of talking tough but failing to take action. In the most significant step he will outline detailed plans to limit access to pornography.

The Daily Mail, which has been running a campaign to crack down on child pornography, reported that the prime minister will say: "By the end of this year, when someone sets up a new broadband account the settings to install family-friendly filters will be automatically selected. If you just click 'next' or 'enter', then the filters are automatically on.

"And, in a really big step forward, all the ISPs have rewired their technology so that once your filters are installed, they will cover any device connected to your home internet account. No more hassle of downloading filters for every device, just one-click protection. One click to protect your whole home and keep your children safe.

"Once those filters are installed, it should not be the case that technically literate children can just flick the filters off at the click of a mouse without anyone knowing. So we have agreed with industry that those filters can only be changed by the account holder, who has to be an adult. So an adult has to be engaged in the decisions."

The prime minister will also announce that possession of "extreme pornography", which includes scenes of simulated rape, will be outlawed by the government. It is illegal to publish such pornography and illegal to possess it in Scotland but not in England and Wales.

Cameron will say: "There are certain types of pornography that can only be described as 'extreme' … that is violent, and that depicts simulated rape. These images normalise sexual violence against women – and they are quite simply poisonous to the young people who see them."

The Rape Crisis group welcomed the announcement by the prime minister, who will also say that the government is to legislate to ensure that videos streamed online are subject to the same rules as those sold in shops. Fiona Elvines, of Rape Crisis South London, said: "We are heartened by the government's announcement that it will close the loophole in existing extreme pornography legislation.

"The government today has made a significant step forward in preventing rapists using rape pornography to legitimise and strategise their crimes and, more broadly, in challenging the eroticisation of violence against women and girls."

In some of his toughest language against the world's largest internet providers, the prime minister will warn them they face a duty to block "sick" people searching for illegal sites online. "I have a very clear message for Google, Bing, Yahoo and the rest. You have a duty to act on this – and it is a moral duty. If there are technical obstacles to acting on [search engines], don't just stand by and say nothing can be done; use your great brains to help overcome them.

"You're the people who have worked out how to map almost every inch of the Earth from space; who have developed algorithms that make sense of vast quantities of information. Set your greatest brains to work on this. You are not separate from our society, you are part of our society, and you must play a responsible role in it."

The move by Twitter to introduce a new tagging system, revealed exclusively to the Guardian, has come independently of UK pressure.

© Guardian News and Media 2013