Sky, Virgin Media, and Talk Talk are preparing to block internet pornography for their subscribers in a bid to make youngsters “safer” online.

By the end of the year, the ISPs plan to make pornography “opt-in” for subscribers, so new users would need to tick a checkbox when signing up, and current customers will be sent messages asking whether they would like to opt-in to pornography or receive the “cleanfeed”. With around 12 million subscribers between them, this change will have a major impact online.

Pornographic content will also be blocked at public Wi-Fi access points, with major providers BT, Virgin, and O2 also signing up to this cleanfeed.

By blocking content on the ISP level, the content will be blocked on all devices connecting via that connection whether it is a laptop, a games console, a tablet, or a smartphone.

The ISPs have categorised the content that could be blocked into nine categories including pornography, gambling, self-harming, and suicide.

Whilst the cleanfeed on public WiFi makes sense for a number of reasons, making censorship on by standard on home connections set a worrying precedent. The changes will cause awkward conversations, but that is less of a problem than the issues these feeds can cause for legal businesses. Why should legal and regulated gambling and adult businesses have a large proportion of their website traffic blocked by default? These are not filters of illegal material, but moral filters, where the morality of what is blocked is arbitrarily set by a handful of unaccountable people.

If you sign up to having all this “objectionable” content blocked, then what is to stop those same people blocking other content they find distasteful such as protest, and questions asked about their companies? These are not legal vs illegal feeds – there is nothing to stop Sky blocking independent websites that are discussing the phone hacking scandal which was so embarrassing for the company, or discussing whatever the next scandal may be.

Defacto censorship is always a problem, not for what is censored at the time, but the precedent it sets for what will be blocked in the future.