Q&A was inundated with 2000 questions from the public about the Government's hugely unpopular policy, and the audience last night ridiculed Senator Conroy by laughing at a number of his responses. Senator Conroy, under siege after this website's report yesterday afternoon that an innocuous link containing Henson's artistic photographs of young boys had been added to the blacklist, said "the classification board looked at this website and actually said it's PG".

"A technical error inside ACMA I'm advised included it ... but it was actually cleared by the Classification Board so it shouldn't be on the list," Senator Conroy said. "I've asked ACMA in the last few hours to go through their entire list again to see if there are any other examples of this." The Government plans to use the top-secret blacklist, compiled by the Australian Communications and Media Authority (ACMA), as the basis of its internet filtering scheme, with sites on the list blocked for all Australians.

But the presence of innocuous sites on the blacklist, such as that of a Queensland dentist, a school canteen consultancy and an animal carer, and euthanasia sites, abortion sites, fetish sites, gambling sites, regular porn sites and a site containing harmless Henson photographs, were only revealed after the list was leaked by the Wikileaks website this month. The Opposition's communications spokesman, Nick Minchin, said: "This error only came to light because content from the secret blacklist had been publicly leaked. Under Senator Conroy's regime how many similar errors will result in the wrongful filtering of legal sites and content?"

Greens Senator Scott Ludlam said: "If the whole net censorship debate has done one good thing, it's shown us just how flawed the existing system is, let alone the Minister's proposed radical expansion of it."

Asked to comment on why a dentist's site was included on the list, which is supposed to target "illegal" material, Senator Conroy said it was the result of a "Russian mob" that targeted small businesses and published questionable content on their websites. However, despite that dentist's claims that the site was cleaned up and moved to a different host several years ago, the website remained on the blacklist.

"I don't actually have a problem with trying to combat the Russian mob putting material that would be refused classification and trying to publicise it worldwide," Senator Conroy said. The Minister continued to claim last night that his proposed censorship regime was sound because it targeted only "refused classification" content, however, the RC classification includes sites that are perfectly legal to view, such as regular porn sites and fetish sites.

He rejected claims he would be blocking political content despite revelations that Henson photographs, pro-euthanasia material and anti-abortion websites had been included on ACMA's blacklist. "When he wasn't blaming the Russian Mob, the Minister was still invoking hateful, extreme content and protesting that they don't intend to censor 'political' content," said Colin Jacobs, spokesman for the online users' lobby group Electronic Frontiers Australia. "But this doesn't address questions of how the secret list is administered, how the Government hopes to classify millions or billions of web pages without making any mistakes, or why an expensive national filter has to be applied at the ISP level in the first place."

Senator Conroy also admitted last night that proposed internet filters would not be effective on peer-to-peer networks, which experts say is where the vast majority of child pornography is traded. This contradicts his comments when announcing live trials of his censorship scheme in December last year, when he said the Government would test technology that could filter peer-to-peer networks.

The Classification Board said it was looking into last night's hacking of its website, which has now been taken offline. A message written on the site read: "This site contains information about the boards that have the right to CONTROL YOUR FREEDOMZ. The Classification Board has the right to not just classify content (the name is an ELABORATE TRICK), but also the right to DECIDE WHAT IS AND ISNT APPROPRIATE and BAN CONTENT FROM THE PUBLIC. We are part of an ELABORATE DECEPTION from CHINA to CONTROL AND SHEEPIFY the NATION, to PROTECT THE CHILDREN. All opposers must HATE CHILDREN, and therefore must be KILLED WITH A LARGE MELONS during the PROSECUTION PARTIES IN SEPTEMBER. Come join our ALIEN SPACE PARTY."