The UK online safety regulator Ofcom has fined the US messaging platform 4Chan a total of £520,000 for failing to comply with various aspects of the Online Safety Act.

It includes £450,000 for failing to put in age checks to prevent children from seeing pornography on the platform.

However, a lawyer representing the company - which has previously said it won't pay such fines - has responded to the demand with an  AI-generated cartoon image of a hamster.

In a follow-up post on X, 4Chan's lawyer Preston Byrne wrote: "In the only country in which 4chan operates, the United States, it is breaking no law and indeed its conduct is expressly protected by the First Amendment."

The fines also include £50,000 for failing to assess the risk of illegal material being published and a further £20,000 for failing to set out how it protects users from criminal content.

4Chan has refused to pay all previous fines from Ofcom.

Ofcom responded to the BBC's request for a reply to Byrne's posts with a statement from Suzanne Cater, its director of enforcement.

"Companies – wherever they're based – are not allowed to sell unsafe toys to children in the UK. And society has long protected youngsters from things like alcohol, smoking and gambling. The digital world should be no different," she said.

"The UK is setting new standards for online safety. Age checks and risk assessments are cornerstones of our laws, and we'll take robust enforcement action against firms that fall short."

She did not comment on the image 4Chan had published in response to the fine.

In February 2025 Vice President JD Vance told an audience of world leaders at the AI Summit in Paris that the administration was "growing tired" of foreign countries attempting to regulate its tech businesses.

4chan is known to be an anarchic messaging space, and has often been at the heart of online controversies since it launched 22 years ago.

Ofcom has issued nearly £3m in fines to tech companies around the world for breaches of the UK's online safety laws.

However most of this money has not yet been received.

Ofcom says one company called Itai Tech, which runs a nudification site, paid its fines of £50,000 and £5,000, and blocked UK users from its service, while two other firms added age verification.

It added that other fines were still within their timeframe to be paid, and it was "considering next steps" for those who had missed payment deadlines.

In December the regulator told the BBC it had never heard from a company running 18 porn sites, which it had fined £1m, although the company did later add age verification to its platforms.

Last month Pornhub restricted access to its website in the UK, blaming the introduction of stricter age checks, and said its traffic had fallen by 77%.

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Accounts pretending to have conditions like Down's Syndrome have amassed thousands of followers

Ofcom's £1.35m fine on 8579 LLC is the largest it has levied under the Online Safety Act so far.

Police cannot tackle the issue alone, the NCA says, and technology companies must do more.

Separately, message board 4chan says it will refuse to pay an expected £520,000 fine from the media regulator.

Regulator Ofcom now has to decide whether to accept the broadcaster's plan for its northern news service.