Wikipedia co-founder Jimmy Wales, a key technology adviser to prime minister David Cameron, has slammed the government's demand that ISPs should introduce porn filters by default, saying the move is "ridiculous".
Wales told Channel 4 News the proposals would not help stop illegal content appearing and being accessed online.
Wales advises the government on open access to information online. He told Channel 4 News: "When Cameron uses the example of paedophiles who are addicted to internet porn, all that these plans would do is require them to opt in [to access legal porn]". "It's an absolutely ridiculous idea that won't work."
Sections of the media have campaigned for internet filters to be turned on automatically for web services, to help prevent porn and "offensive" content being viewed by minors.
But others are against the move, saying it is up to individuals to view whatever legal content they want on the internet unhindered. They also say default filters would give parents a false sense of security about what their children are not watching, as filters can be turned off or bypassed. They also point out filters aren't 100 percent reliable anyway.
But under government plans, by the end of 2014 every new contract with a UK ISP will ask customers to opt in to receive adult content.
Cameron said the ISPs were "rewiring their technology" to "keep children safe". The filters are only being brought in automatically for new contracts, not existing ones, and cover services offered by BT, Virgin, Sky and TalkTalk. The ISPs will also invite existing customers to use the "family friendly" filters.
Wales said existing legislation covering criminal activity online was already adequate. He said what the police needed were more resources to tackle online crime.