17 July 2025 — Next week, on 22 and 23 July 2025, the High Court of Justice in London will hear the Wikimedia Foundation’s legal challenge to the Categorisation Regulations of the United Kingdom (UK)’s Online Safety Act (OSA). 

The Wikimedia Foundation, the non-profit that operates Wikipedia and other Wikimedia projects, announced its legal challenge earlier this year, arguing that the regulations endanger Wikipedia and the global community of volunteer contributors who create the information on the site.

“The Court has an opportunity in this case to set a global precedent for protecting public interest projects online,” said Stephen LaPorte, General Counsel at the Wikimedia Foundation. “Wikipedia is the backbone of knowledge on the internet. It’s the only top-ten website operated by a non-profit and one of the highest-quality datasets used in training Large Language Models (LLMs). We trust the Court will protect Wikipedia—a vital encyclopedic resource—from rules crafted for the internet’s riskiest commercial sites and, in doing so, safeguard the open internet for everyone”.

Information on Wikipedia is written and curated by a global community of nearly 260,000 volunteer contributors. These volunteers set and enforce policies to ensure that information on the platform is fact-based, neutral, and attributed to reliable sources. Over the last 25 years, this human-centered content moderation model has established Wikipedia as an unparalleled resource for reliable information in over 300 languages; its 65 million articles are viewed more than 15 billion times per month worldwide.

The Wikimedia Foundation shares the UK government’s commitment to promoting online environments where everyone can safely participate. The organization is not bringing a general challenge to the OSA as a whole, nor to the existence of the Category 1 duties themselves. Rather, the legal challenge focuses solely on the new Categorisation Regulations that risk imposing Category 1 duties (the OSA’s most stringent obligations) on Wikipedia.

If enforced on Wikipedia, Category 1 demands would undermine the privacy and safety of Wikipedia’s volunteer contributors, expose the encyclopedia to manipulation and vandalism, and divert essential resources from protecting people and improving Wikipedia, one of the world’s most trusted and widely used digital public goods.

For example, the Foundation would be required to verify the identity of many Wikipedia contributors, undermining the privacy that is central to keeping Wikipedia volunteers safe. In addition to being exceptionally burdensome, this requirement—which is just one of several Category 1 demands—could expose contributors to data breaches, stalking, lawsuits, or even imprisonment by authoritarian regimes. Additional details about the concerning impacts of the Category 1 duties on Wikipedia are available in this blog post.

The Wikimedia Foundation will be joined in the case by longtime UK-based volunteer Wikipedia contributor User:Zzuuzz as a joint claimant. Their voluntary participation highlights what is at stake in this case for the everyday people who read and contribute to Wikimedia projects. It presents the perspective of a Wikipedia volunteer on how the OSA Categorisation Regulations directly threaten the ability of contributors to participate in knowledge sharing on Wikipedia, as well as compromising their rights to privacy, safety, free speech, and association. 

The legal challenge is the first to be issued against the OSA’s Categorisation Regulations, as well as the first with a volunteer Wikipedia editor participating as a joint claimant. It follows years of dialogue with regulators and policymakers, in which the Foundation expressed its concerns, as well as warnings from the UK Parliament and civil society.

“Our concerns on the looming threats to Wikipedia and its contributors remain unaddressed”, said Phil Bradley-Schmieg, Lead Counsel at the Wikimedia Foundation. “We are taking action now to protect Wikipedia’s volunteers, as well as the global accessibility and integrity of free knowledge. We call on the Court to defend the privacy and safety of Wikipedia’s volunteer contributors from flawed legislation”.

Wikipedia and other Wikimedia projects are safe and important resources through which people across the UK—and the wider world—learn, share knowledge, collaborate, and gain media literacy. Thousands of volunteer Wikipedia contributors are based in the UK, and Wikipedia hosts content from cultural institutions such as the British Library and Wellcome Collection. Content on Wikipedia and other Wikimedia projects was viewed 776 million times last month in the UK alone. Moreover, Wikipedia is used to preserve and promote cultural heritage in the UK, including Indigenous and minority languages such as Welsh. The Welsh language version of Wikipedia is the single most popular Welsh language website in the world and is an official component of the curriculum in Wales.

The hearings at the Royal Courts of Justice (Administrative courts of the King’s Bench Division) in London, are expected to be open to the public. The case reference is AC-2025-LON-001365, and the courtroom location will be announced here shortly before the hearing. The Court will issue its decision following the hearing, though the exact timing of the announcement is not known.

The personal identity of User:Zzuuzz, the volunteer joining the challenge, will remain confidential and protected by the law and the Foundation. 

For media inquiries, please contact press@wikimedia.org. 

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About the Wikimedia Foundation

The Wikimedia Foundation is the nonprofit organization that operates Wikipedia and other Wikimedia free knowledge projects. Our vision is a world in which every single human can freely share in the sum of all knowledge. We believe that everyone has the potential to contribute something to our shared knowledge and that everyone should be able to access that knowledge freely. We host Wikipedia and the Wikimedia projects; build software experiences for reading, contributing, and sharing Wikimedia content; support the volunteer communities and partners who make Wikimedia possible. The Wikimedia Foundation is a United States 501(c)(3) tax-exempt organization with offices in San Francisco, California, USA.