No one wants children to access porn online.

Working out the best way to protect them from the darker corners of the internet is a thorny issue that the government is trying to tackle.

But when the Department of Education last week released the results of its public consultation on whether or not pornography should be automatically banned by internet providers (unless a subscriber “opted in” to receive adult content), the overriding message was clear.

“There was no great appetite among parents for the introduction of default filtering of the internet,” the Department declared. What parents wanted, instead, was the option to filter content and better knowledge of how to do that in order to protect their children from online porn.

After months of threatening internet providers with an automatic porn ban, the Government seemed to relent and recognise that policing the internet was primarily a job for parents, not the state.

Yet in the course of just a few days Downing Street appears to have swung back the other way after receiving a mauling in the Daily Mail – the newspaper which has campaigned vigorously for automatic porn restrictions and was furious that their call for an automatic ban had been rejected as unworkable.

Writing in today’s Mail, Mr Cameron described online pornography as a “silent attack on innocence” and instead announced plans to force internet providers to bring in new porn filters for any households with children present. The plans stop short of the “opt-in” porn ban that backbench Tory MP Claire Perry has been campaigning for. But it would nonetheless bring in some of the heaviest mandatory state-sanctioned internet filters in Europe.

What Mr Cameron envisages is a system whereby anyone installing a new computer at home and connects to the web will be asked whether there are any children in the home. If there are, parents will be automatically required to tailor their internet filters. If a parent skips too quickly through the filter process the highest restrictions will automatically remain in place.

It will be the job of internet providers, rather than computer manufacturers, to come up with the filter software.

Downing Street officials insisted today that the announcement was not a U-turn on porn filters and that Mr Cameron’s announcement was simply a way of illustrating what the Government has planned to give parents more control. But the onus is nonetheless firmly placed on internet providers to come up with mandatory filters with Whitehall sources indicating that a “legislative backstop” would be brought in they refused to co-operate.

That has caused concern among web providers, most of whom already offer content filters to their customers as a matter of course. One source involved in negotiations with the Government described Mr Cameron’s announcement as an example of “goal posts being moved”.

Critics of the plans called described them as “muddled and unworkable”.

“This is a back-of-the-fag-packet policy reversal announced after the Government’s own public consultation decided just a week ago that further filtering wouldn’t work,” said Jim Killock, from Open Rights Group, which campaigns against digital restrictions.

Nick Pickles, from the Big Brother Watch, added: “Mr Cameron seems to be suggesting a combination of network filtering and device filtering that isn’t even available at the moment, let alone possible. The danger here is it will alienate the ISPs who thought they’d been involved in the consultation process.”

Concern that young people are increasingly able to access pornography through computers, phones and tablets is universal. The disagreement tends to be over what effect porn has on children and where the responsibility lies for monitoring what children get up to online.

In Britain most parents are already being proactive in blocking adult content or tracking their children’s browsing habits. A recent study into European computing habits by the London School of Economics – one of the most comprehensive every undertaken – found that 54% of parents blocked or filter websites at home whilst 46% tracked sites visited by their children making Britain the most proactive country in Europe for filtering.

Mrs Perry, a mother of two who represent Devizes in Wiltshire, has now been promoted by Mr Cameron to advise the government on “the sexualisation and commercialisation of children.” In a statement released yesterday she said she would push for “more robust filters for internet content in our homes” and try to “to improve education for parents and children about online safety.”

Peter Warren, Cyber Security Research Foundation, says the government should concentrate on the latter proposal rather than the former if it wants to protect young people from porn.

“It’s easy to call for blanket bans but the technology is far ahead of anything you can do in those terms,” he said. “What would make far more sense is to raise the risks of going to porn sites. We need a massive campaign to raise awareness s among the public at large on all things to do with computer security and the internet. That is not just doable, it will have tangible results.”

Q&A: What now?

What is being proposed?

Downing Street wants to introduce a mandatory internet filter system for any new computer for any household where a child is present.

How will it affect internet users?

Parents will have to decide what level of protection they want to place on their new computer before they log on to the internet for first time.

Will it work?