That's not what he says—all porn sites will have to gather and retain proof of customer identity. But everything leaks, so it's what he meant.

That's not what he says, of course: he just says that all porn sites will have to gather and retain proof of identity (eg credit-card details) to ensure that their users are over 18 or they'll be blocked by the Great Firewall of Cameron — but everything leaks.

Let's start by saying that this will be totally, absolutely ineffective at preventing kids from seeing porn. Never underestimate the power of a kid who is cash-poor and time-rich. The Chinese government has the power to harvest your organs and give them to party members if you mess with their Great Firewall, and they make all the networking equipment and they have the world's largest supply of talented network engineers — and they can't even stop their residents from accessing hippie mystical tai-chi-plus-plus religious cult woo. We're talking about sex, here. We have a name for organisms that aren't obsessed with reproduction: extinct. David Cameron vs four billion years of evolution: I give long odds on the reigning champ. Like, four billion to one.

But this isn't just totally ineffective at preventing bad outcomes: it creates even worse problems. Censorware is like regexps for politicians: now you have two problems. Because everything leaks. I don't just mean these fools. I also mean these delightful fellows.

There is exactly one gold standard for not leaking user data: not gathering or retaining it in the first place.

So what do you get when you combine a database of the porn-viewing habits of everyone in the UK, cross-referenced with their credit-card details? Well, if you're presently worried that your cheating boss might be embezzling your company into the dirt to pay off his blackmailer, imagine that, on a national scale, only the blackmailers get to sort by net worth.

Nice one, Dave. More evidence that you're the tech PM the UK needs for the twenty-first century.

The top 10 most frequented pornography sites in the UK take 52% of traffic and have next to no controls. Government sources said "all provide free content upfront and none have robust age verification to protect under-18s in place at present, whilst DVDs containing explicit pornographic content are subject to age controls for purchase in licensed sex shops." The aim is to ensure that the rules that apply offline apply online, giving parents the peace of mind of knowing that their children can use the internet safely. Cameron said his government was working "to make the internet a safer place for children, the next step in this campaign is to curb access to harmful pornographic content, which is currently far too widely available. "I want to see age restrictions put into place or these websites will face being shut down."

Cameron tells pornography websites to restrict access by children or face closure [Patrick Wintour/The Guardian]