Mr Cameron last month announced a new agreement with internet service providers on new filters that would block access to online pornography unless customers explicitly opted in to accessing them.
But Jimmy Wales, the founder of Wikipedia, said he didnt think the plans were needed. He said: It's an absolutely ridiculous idea. It won't work. The software you would use to implement this doesn't work. Additionally when we use cases of a paedophile who's been addicted to child porn videos online, you realise all that Cameron's rules would require him to do is opt in and say 'Yes, I would like porn please'."