The UK's plans to introduce mandatory age checks for viewing pornography online could involve verifying users' identities via third parties such as banks, mobile operators, credit agencies, or even the post office. The country's Conservative party pledged to introduce such age checks earlier this year, and following their recent re-election, discussions have reportedly begun between the technology industry and the government over ways to implement the checks.

"Royal Mail knows who you are."

The Digital Policy Alliance (DPA), a nonpartisan body that offers advice on technology policy in the UK, has suggested using "information already on file" to carry out the checks. "Nobody in the UK wants a centralized identity database," Dr Rachel O’Connell, an expert on online child safety advising the DPA, told The Guardian. "The way around that is that Royal Mail knows who you are, your mobile operator knows who you are."

O'Connell suggests that users visiting porn sites could choose which organization would verify their ID, with their request and the organization's reply transmitted through an "anonymizing hub" to protect their identity. A regulator could then block sites that don't offer age checks, with the Authority for Television on Demand — the body that regulates online video streaming — expected to be given this role.

Numerous legal and technical uncertainties

However, despite broad, cross-party support for mandatory age checks, there are still numerous legal and technical uncertainties. The UK doesn't have the best track record when it comes to policing online content, with government-requested ISP filters introduced from 2013 criticized for blocking sex education and sexual abuse help sites. It's also not clear how the age checks would be applied to non-UK porn sites, although The Guardian reports that MindGeek — owner of numerous "tube" sites including Pornhub — has "joined discussions" with the DPA.

There are also worries about censorship, with the UK's prime minister David Cameron outlining plans earlier this month to crack down on online extremism, including any individuals deemed to be a "threat to the functioning of democracy." The home secretary Theresa May has also made clear the government's ambition to revive the so-called Snooper's Charter, a bill that requires internet and phone companies to record metadata about users' texts, calls, emails, and browsing habits for a year.