Prime Minister David Cameron may not be quite the “pitiless blank-eyed hell wraith” Charlie Brooker portrayed in yesterday’s Guardian, but he does have some pretty frightening ideas about the Internet. This morning the Prime Minister announced, at a meeting with the Christian charity Mother’s Union, that four of the UK’s biggest ISPs will henceforth require users to opt in if they want to view pornographic material – thereby creating a commercially-owned and controlled database of…