Dozens of pornography websites are under investigation over whether they are flouting new online safety laws for children.
Four companies that run platforms hosting adult content are being probed by Ofcom over whether they implemented methods to verify the age of users.
It comes after The Standard revealed that at least 30 sites were still showing pornographic material without asking viewers for proof of age hours after the Online Safety Act came into force on Friday.
The new rules aim to protect Under-18s from viewing harmful content, which includes sexually explicit posts.
Companies that ignore the changes could be fined up to £18 million, or 10% of worldwide revenue.
On Thursday, Ofcom announced it had opened formal reviews into 8579 LLC, AVS Group Ltd, Kick Online Entertainment S.A. and Trendio Ltd and whether they had effective age checks across 34 porn sites.
Collectively, the websites boast more than nine million unique monthly UK visitors, the communications watchdog said.
The new cases add to 11 ongoing probes into 4chan, an online suicide forum, seven file-sharing services, First Time Videos LLC and Itai Tech Ltd.
Some websites are following the strict guidelines. Reddit has already adhered to “regulator approved age assurance methods” to prevent those under the age of 18 from accessing “certain mature content”.
Pornhub — the world’s biggest porn site, which is accessed by approximately 15 million people in the UK — has introduced credit card and ID checks to ensure account holders are old enough.
Platforms are also required by the new regulations to make sure age verification procedures do not jeopardise their privacy or deny people access to lawful content.
xHamster — an adult video sharing website — has partnered with London-based software firm Yoti to vet its visitors securely and privately.
Yoti’s facial recognition technology accurately estimates a person's age based on a selfie, which then creates a digital identity wallet for future use.
According to new research by Ofcom, 8% of eight to 14-year-olds in the UK visited a porn site in one month.
An Ofcom spokesman: "Where we identify compliance failures, we can require platforms to take specific steps to come into compliance.
"Where appropriate, in the most serious cases, we can seek a court order for business disruption measures, such as requiring payment providers or advertisers to withdraw their services from a platform, or requiring internet service providers to block access to a site in the UK."
