David Cameron’s announcement yesterday that the UK government will force ISPs to adopt a “default-on” filtering system for pornography drew fierce criticism from ISPs and rights campaigners. However, an unlikely critic of Cameron’s plan is the country’s top child abuse investigator Jim Gamble, chief executive of the Child Exploitation and Online Protection Centre (CEOP), who said the blacklist currently used to filter the vast majority of UK internet connections had been a "fabulous success".

The question could be asked that if it is such a success, then why is the government seeking to regulate a program already working? In 2009, only small "boutique" ISPs had yet to adopt CEOP's filtering and the Home Office estimated roughly 95 per cent of internet users were covered under the child abuse filtering regime. David Cameron was actually echoing a speech made by Vince Cable after claims that Mark Bridger, who murdered April Jones had accessed child porn on his computer. Cable admitted it was "very, very difficult" to police the internet, but added: "Mark Bridger appears to be influenced by watching child pornography on the internet. Ultimately, this has got to come from the public; if they see any evidence of this happening, of getting it to the police immediately.”

Cable’s remarks, however, have been criticised by Daniel Foster of 34SP.com, a British-based ISP who stated, "David Cameron's clampdown on porn, borne out of the most painstaking investigation into paedophilia the UK has ever seen, coupled with the convictions of some of the most prolific sex offenders, is at best, more misguided regulation by those who don't understand it and at worst, a cynical ploy to appease a public who feel betrayed.”

"Forcing a search engine to block access is wholly ineffective, simply because the types of image targeted in this announcement are invariably shared over private networks and not found by a simple image search. Blocking current search terms will only lead to new ones being used - the offenders will offer a constantly moving target.”

E-Governance Professor at the University of Strathclyde Lilian Edwards added, “These places are sometimes known as darknets, eg P2P sites for swapping illegal material - or "hidden services", the phrase the IWF uses in its latest report to describe anonymised websites where new paedophiles material often makes its first appearance.”

Cameron insists that more needs to be done, even as ISPs voluntarily comply with most government recommendations -- like "splash pages" that warn users they are attempting to view illegal material. The prime minister will call on firms to go further, with splash screens warning of consequences "such as losing their job, their family, even access to their children" as a result of viewing the content.

But Foster stated "History shows us that they will be quicker at keeping this target moving than law enforcement will be at catching it. To say that pornography is 'corroding childhood' is extreme. Having criticised the previous government for operating a nanny state, this reeks of hypocrisy. The fact that there is plenty of widely-adopted filtering software readily available means that internet users are already acting autonomously in policing content in their own homes.”