Children"s charities in the UK have expressed what they call "serious concerns" that some Internet service providers have still not blocked websites showing child sex abuse.
The British government asked ISPs to block child porn, according to a list provided by the Internet Watch Foundation, before the end of 2007. However, 5 percent of broadband suppliers in the UK are still not blocking sites listed by the IWF.
According to BBC News, the NSPCC"s Zoe Hilton said, "Allowing this loophole helps feed the appalling trade in images featuring real children being seriously sexually assaulted. Over 700,000 households in the UK can still get uninterrupted and easy access to illegal child abuse image sites."
While the Internet Service Providers Association believes that smaller ISPs have not opted-in because of the costs involved, Zen Internet, one of the ISPs not blocking sites, believes that the system is ineffective.
The company said in a statement, "Zen Internet has not yet implemented IWF"s recommended system because we have concerns over its effectiveness. Our Managing Director, Richard Tang, is going to meet Peter Robbins the Chief Executive of the IWF to discuss these concerns."
The system does seem to have its flaws. In December last year, Wikimedia sites were restricted or blocked by some ISPs in accordance with the list provided by the IWF, before the ban was rescinded.
Dr Richard Clayton, a Cambridge computer scientist and long-term critic of the Internet Watch Foundation"s work, also believes that it is an ineffective system. "This material tends to be held on paid-for sites or is held by people who don"t publish it to the world because they don"t want to get arrested," he told the BBC"s Rory Cellan-Jones, who writes on the BBC"s dot.life technology blog.
"Everybody thinks they"ve done something by blocking this stuff but in practice it makes very little difference to who sees it and it"s quite expensive."