Analysis: can Cameron win his war on online porn?

The prime minster's speech yesterday promised a UK freed from the apparent dangers of adult material. But can such censorship really be achieved?

Prime minister David Cameron's announcement that access to pornography will be switched to a "default off" state for the UK's major internet service providers was a potentially welcome decision for those concerned about what unsupervised children can view online, but it almost completely lacks validity on a technical level.

In his speech, Cameron said that ISPs - which so far include TalkTalk, Sky, Virgin Media and BT - have "rewired" their technology to "cover any device in your home".

First off, believing there is any form of backend technology that can truly achieve this is unwise. There isn't, and such a statement feels like it's seeking to absolve parents of responsibility. This is a potentially dangerous thing to publicly state, and suggests little research has been done before declaring a policy that won't be easily enforceable.

Cameron's plan involves having ISPs engage "filters" to prevent certain adult content being viewed without users first "opting in" to see it. Presumably ISPs will work with URL and keyword filtering, as they already do when censoring content such as torrent sites.

The filters will be provided by specialist companies who are, as yet, unnamed, and their individual techniques unclear.

But even if these carpet bombing approaches to security do some good, they can be easily circumvented using proxy server or virtual private network access – which can already be rented for a pittance and executed by school children.

Cameron said search engines have a "moral responsibility" to help him to achieve his aims, but the world's major search engines already do filter out adult content using various selectable (and password protectable) safeguards.

Illegal material – such as that involving child abuse – cannot ordinarily be accessed through Google or any other major search engine at all.

Yahoo's Flickr photo-sharing site, for example, flags and drops from search algorithms material considered to be adult in nature.

The company's recently acquired Tumblr blogging site, meanwhile, introduced a similar filter last week. However, a few days later the "not safe for work" (NSFW) content was restored, due to popular demand, which perhaps highlights the main problem with what Cameron's proposing.

That is: what is pornography? What is decency?

The problem with this kind of blanket censorship is that it relies on an entirely automated censorship process. A photograph of the Venus de Milo could prove just as taboo as the most hardcore pornographic scene to a computer algorithm. The danger is that a lot of content that most adults wouldn't have a problem with will be put beyond reach of the average user.

Analysis: can Cameron win his war on online porn?

The prime minster's speech yesterday promised a UK freed from the apparent dangers of adult material. But can such censorship really be achieved?

The other key problem with Cameron's plan is that it will do nothing to prevent access to the "darkest corners of the internet" where the vilest and most depraved content tends to reside. The vast majority of child pornography is accessible not by typing keywords into Google, but by accessing a host of peer-to-peer networks that undesirables congregate around to exchange illegal material.

This has been the way ever since the internet reached ubiquity in the 1990s. The material has, after all, always been illegal, and could never exist on the "surface" of the web as it would land its distributors in almost instant (and very deep) legal trouble.

Yet Cameron yesterday declared that "we" - meaning his government - will "give CEOP [Child Exploitation & Online Protection Centre] and the police all the powers they need to keep pace with the changing nature of the internet".

The Prime Minister of the United Kingdom does not possess the powers to infiltrate illegal, underground online networks that are based outside the UK and inhabited by global criminals, and so those powers are not his to give away.

Pop-up warning

Jim Gamble, the former boss of CEOP – the very organisation Cameron named as the recipients of his "powers" yesterday – told the BBC that the measures the Prime Minister has been speaking of are "a pop-up that paedophiles will laugh at", and that it was important to "get to the root cause" of child pornography by going directly after the criminals who create it for distribution.

At a time when the government perhaps wishes to divert attention from accusations of feeding sensitive information on UK citizens to the US government through Prism, a good bit of concerned parent-style tubthumping aimed at the technically unsophisticated Mumsnet crowd might seem like a good tactical move.

On an IT level, though, it's close to palpable nonsense, and Cameron would be advised not to again put his voice - and whatever passes for his reputation these days - behind such ill-considered, underdeveloped technical ideas.