One of the world’s most visited pornography websites is being investigated by the UK’s communications watchdog over concerns it can still be accessed by children.

Pornhub’s age checking regime may not be “highly effective”, according to Ofcom, and could be in breach of online safety laws requiring strict measures to prevent under-18s from accessing sexually explicit content.

Ofcom is investigating Pornhub’s use of Apple’s age verification process to determine whether someone is the appropriate age for viewing pornography.

Pornhub had blocked access to new UK users in response to the Online Safety Act, but announced in May it would use so-called device-level checks, meaning users in the UK who had confirmed they were 18 or older through Apple’s age-verification process would be able to access Pornhub and be “served a standard adult user experience”.

Ofcom raised concerns over that decision on Wednesday. Announcing the investigation, it said the act was “clear that it is the service provider’s responsibility to ensure that any age assurance process is highly effective – no matter at what stage an age check occurs”.

The regulator added: “We are concerned that Aylo [Pornhub’s owner] may not have conducted sufficient due diligence and testing before implementing its new age assurance process.

“As a result, we are concerned that Aylo’s process may not be highly effective at preventing children from seeing pornography.”

Ofcom said its investigation was not focusing on Apple’s age checks specifically, but on whether Pornhub owner Aylo’s reliance on that system was in line with the act – because it is the content provider’s responsibility to ensure whether its age-checking measures are robust or not. Some Ofcom checks of Aylo’s device-level checking system have shown the website could have been accessed by children.

George Lusty, Ofcom’s director of enforcement, said: “Online age checks are a vital protection to prevent children from encountering inappropriate or harmful material, including pornography.

“We expect tech firms to ensure age checks are highly effective before introducing them. Anything less could leave children at risk.”

A finding that Aylo broke the law could result in a fine of up to £18m or 10% of the company’s global revenue, whichever is greater.

Beeban Kidron, a crossbench peer and prominent campaigner for child internet safety, said she hoped the Ofcom investigation would result in a renewed drive for effective age checking.

“Extremely effective privacy preserving age assurance has been possible for years. It is a question of corporate priorities. I hope the action by Ofcom pushes it up the priority list not only at Pornhub but accross the sector,” she said.

In July, Ofcom said there had been “significant progress” in implementing age checks across tech platforms in pornography, social media, dating and gaming. It said the proportion of children who encountered highly effective age checks increased from 25% to 43% between July 2025 and January this year. It added that a minority of children (8%) had attempted to access pornography, and half of them reached sites with age checks in place.

Nonetheless, it said “more action is needed” on age checking, particularly with an under-16 social media ban being implemented next year.