Defending the right of people to publish and watch porn is an uphill battle. Nice, “liberal” people aren’t always as liberal as they think, and many think sexual imagery is a Bad Thing, and shouldn’t fall under the umbrella of free expression. So there was a strong boost for the anti-censorship movement in December when the UK “porn filters” were rolled out, and it turned out that they weren’t really much to do with porn at all.

Unfortunately, there isn’t much of a genuine free speech lobby in this country (it was the discovery of this fact that led me to set up the Sex & Censorship campaign). However, the filters blocked such broad areas of content that far more vocal groups have been spurred into opposition, and have strengthened the anti-censorship movement. The revelation that a number of gay sites had been blocked, apparently in error, led to outrage from the LGBT community and its supporters. And the inclusion of Sex Education as a category that parents could prevent their teens from accessing caused outrage among many commentators.

The animal protection organisation World Wildlife Fund adopted the panda as its symbol, rather than some endangered species of lizard or beetle, because pandas look cuddly. Saving ugly creatures isn’t a cause that many people will donate to. In the world of anti-censorship campaigning, LGBT and sex education causes are the panda; and yet, many of the “uglier” blocked categories should be just as much a cause for concern as the “pretty” ones. But if people accept that some expression can be censored, then free speech is lost.

Many of the blocked categories have been ignored because they don’t upset any large lobby group, but they should be cause for concern. I have seen no defence, for example for “sites that give information on illegal drugs”. Yet such sites save lives, and fill a role that, in a more sane world, would be carried out by government. The site pillreports.com, for example, is a database of ecstasy tablets on the market. As the site says: ‘Pills sold as “Ecstasy” often include other, potentially more dangerous, substances such as methamphetamine, ketamine and PMA.’ Filtering of drug information doesn’t protect anyone, but simply enforces an anti-drug morality. If allowed to continue, this filtering will doubtless cost teenage lives.

“Sites that promote self-harm” may make for good Daily Mail headlines, but people in distress most need a community of people who understand them. Isolating troubled young people from each other can only be a recipe for disaster. “Sites that describe guns” are also on the list, and illustrate the constant confusion between expression and the physical world. America’s gun lobbyists try to claim that “guns don’t kill people”; this is patent nonsense. Guns do kill people: but there’s no evidence that pictures or descriptions of guns do, and in fact guns are shown daily on TV, often in glamorised ways, without any evidence that this leads to real-world violence.

The option to block social networking sites is perhaps one of the most sinister of all. Depriving children of social contact may be classified as emotional abuse, and yet, because of the endless panic over “online grooming”, many parents may exercise this option. The best way to open a child to the possibility of grooming is to keep them ignorant of the real world. The filters will harm children.

The “file sharing” category is not there to protect children at all, but to protect media corporations from having their content pirated, and probably the result of some clever lobbying activity. Piracy is the problem of the media and entertainment industry, and is a poor excuse for censorship.

The catch-all category of “tasteless and obscene” is another one that preserves conservative ideas of morality, rather than attempt to protect children. Among other things, it includes the ludicrous concept of “how to commit murder”; one would think any teenager conversant with basic physics, chemistry or biology would be able to work that out. Presumably the banning of science classes in school must follow. This category also includes “bathroom humour”, though one must suspect that children can work out fart jokes by themselves, without help from the Internet.

The list goes on and on. In every case, it seems that blocking content can do more damage to child development than the content itself. The category that most divides people is that of hate speech: “sites that encourage the oppression of people or groups based on their race, religion, gender, age, disability, sexual orientation or nationality”. The idea that racism, homophobia and other prejudices can be dealt with by censorship has been fashionable for a few decades, and is attractive to people who dislike prejudice. And yet it is a false promise. Censorship of words that might offend minorities has never solved any underlying problem. Discourse is the solution to bigotry, and this must include angry, “offensive” discourse, however unpleasant it is. Politically correct cures for prejudice do not work; indeed, they leave problems to fester and get worse.

This isn’t to say that prejudice should be left alone: education, discussion, debate, argument and, most of all, leadership are essential. We have a government that wants to protect us from “hate speech” on the one hand, while hinting on the other that immigrants are a threat to our society. Hate can be spread without using hate speech.

And those who think that censorship introduced for “good” reasons will not then be abused are naive in the extreme. The core problem with censorship is that it will always be abused by those with power. Once it is accepted that hateful speech can be suppressed, then the definition of hateful speech will grow inexorably until it is unrecognisable.

Voltaire said: “I do not agree with what you say, but I will defend to the death your right to say it”. Those who are tempted to draw acceptable lines for Internet filtering are missing the point. In a free society, there can be no acceptable lines.