Telcos have clobbered an independent Parliamentary inquiry into online child safety by saying that its recommendations are unworkable.

Prime Minister David Cameron indicated in the House of Commons yesterday that he welcomed the plans, but the broadband industry's lobby group, the Internet Service Providers' Association (ISPA) questioned the proposals.

“Forcing ISPs to filter adult content at the network level, which users would then have to opt out of, is neither the most effective nor most appropriate way to prevent access to inappropriate material online," retorted ISPA secretary general Nicholas Lansman.

"It is easy to circumvent, reduces the degree of active interest and parental mediation and has clear implications for freedom of speech. Instead parents should choose how they restrict access to content, be it on the device or network level with the tools provided," he added.

Earlier this week, chair of the inquiry [PDF], Tory MP Claire Perry, claimed that many kids in the UK were "accessing internet pornography" as well as other "inappropriate" material such as websites that promote self-harm and anorexia.

She described such activity as "hugely worrying".

Perry said:

While parents should be responsible for their children's online safety, in practice people find it difficult to put content filters on the plethora of internet-enabled devices in their homes, plus families lack the right information and education on internet safety. It's time that Britain's Internet Service Providers, who make more than £3bn a year from selling internet access services, took on more of the responsibility to keep children safe, and the government needs to send a strong message that this is what we all expect.

Among other things the report recommended that "ISPs should be tasked with rolling out single account network filters for domestic broadband customers that can provide one-click filtering for all devices connected to a home internet connection within 12 months".

However, the ISPA attacked such a plan, saying that telcos already provided a number of services to customers to help them decide what content should be accessed online at home. "A variety of measures are available to parents and carers and a network level filter should not be viewed as a silver bullet," said Lansman.

The ISPA also questioned "who decides what inappropriate material is".

The 89-page cross-party report failed to offer up a definition. Instead it pointed to how other forms of media police the availability of porn and other content that some consider should be shielded from children's view.

"Very few would argue that the watershed guidelines for TV viewing, the application of film ratings, sensible advertising standards, or top-shelf placement agreements for pornographic magazines represent inappropriate forms of censorship but in the internet world, any attempt to regulate content before the point of delivery can be attacked as censorship unless (but not always) the content is deemed illegal," it said.

The report went on to stop short of "mandatory government censorship of internet pornography" but added that a "new approach" was required.

A network-level 'Opt-In' system, maintained by ISPs, that delivered a clean internet feed to customers as standard but allowed them to choose to receive adult content, would preserve consumer choice but provide an additional content barrier that protected children from accessing age- inappropriate material. This model would emulate the system already used by most major UK mobile phone companies, where access to adult content is blocked until an age verification check is conducted by the network operator, and could use the filtering technology already operating in all schools and on some public Wi-Fi hubs.

ISP TalkTalk has been the one lonely voice in the pro-net-filtering debate, having become the only major telco in Blighty to have implemented network-level anti-malware blockers on its service in May 2011.

The company's CEO Dido Harding penned a blog post on Wednesday in which she said that giving TalkTalk customers an "active choice" over net-filtering had led to one in three new punters switching on the "parental controls".

Unsurprisingly, Harding welcomed the inquiry's findings.

Privacy activist Nick Pickles of Big Brother Watch raised concerns about the inquiry's report on protecting kids online.

"The proposals are made without any qualification or apparent consideration of either the technical impact or the likelihood of avoidance measures. It bears all the hallmarks of a policy proposal that is trying to fix a problem without understanding the solution, or even acknowledging there may be unintended consequences," he said.

"Without offering – or even attempting to offer – a definition of adult content or pornography, the report demonstrates its fundamental failure: this is a moral argument, not a serious attempt to understand the challenges of new technology." ®