Social-networking sites are being subjected to the most stringent censorship. In July, a 17-year-old boy was arrested and questioned by police after he sent insulting tweets to British Olympic diver Tom Daley. The 17-year-old was spared jail but was issued with a “harassment warning.” In March, a 21-year-old student called Liam Stacey was sentenced to 56 days in jail for making crude jokes on Twitter about a then very ill footballer called Fabrice Muamba. …

Now, the Crown Prosecution Service (CPS), the body responsible for prosecuting crimes in England and Wales, is holding a series of meetings to clarify the law on tweetcrimes and FB misdemeanors, and to decide when it is legit, and when it isn’t, to bring criminal charges for trolling or inflammatory speech online. …

Allowing the state to determine the rightness and acceptability of words and ideas doesn’t only lead to gobsmacking levels of censorious authoritarianism—it also robs us, the public, of our right and our responsibility to work out what is true and to challenge what feels like dross in the arena of public debate. As John Milton put it 350 years ago, “Let Truth and Falsehood grapple; who ever knew Truth put to the worse, in a free and open encounter?”