The UK’s online safety regulator has opened a formal investigation into Telegram under the Online Safety Act, examining whether the messaging platform has complied with its duties to protect UK users from child sexual abuse material. It is Ofcom’s most significant enforcement action against a major messaging platform to date.
The UK’s online safety regulator Ofcom has opened a formal investigation into Telegram under the Online Safety Act 2023, examining whether the messaging platform has met its legal duties to protect UK users from child sexual abuse material (CSAM).
The investigation, reported by Reuters, marks a significant escalation in Ofcom’s enforcement of the Act against one of the world’s most widely used messaging services, and a platform that has long drawn scrutiny for its approach to illegal content.
The investigation follows Ofcom’s established enforcement template under the Online Safety Act, which requires user-to-user and search services to assess and mitigate risks of UK users encountering illegal content, including CSAM, and to take it down swiftly when identified.
Ofcom has the power to fine companies the greater of £18 million or 10% of qualifying worldwide revenue for non-compliance, and in cases of serious ongoing non-compliance can apply to a court for business disruption measures, which could include requiring internet service providers to block a platform in the UK.
The opening of a formal investigation does not in itself constitute a finding of wrongdoing. Under the Act’s process, Ofcom first gathers and analyses evidence to determine whether a breach has occurred. If it concludes a compliance failure has taken place, it issues a provisional decision to the company, which then has the opportunity to respond in full before any final decision is made.
The process typically takes several months. The same framework is currently being applied in Ofcom’s ongoing investigation into X, opened in January 2026 following reports that its Grok AI chatbot was being used to generate and distribute sexually explicit images of children.
Telegram’s relationship with UK regulators has been evolving. As recently as December 2024, the platform joined the Internet Watch Foundation (IWF), a UK-based organisation that identifies and removes CSAM, and committed to deploying IWF’s detection tools across public parts of the platform, including hash-matching technology to identify known CSAM and tools to block AI-generated abuse content.
Ofcom’s March 2026 annual review acknowledged that Telegram, alongside X, Discord, and Reddit, had introduced age controls in response to the Online Safety Act.
The new investigation therefore represents a shift: Ofcom, despite that prior progress, has concluded there are sufficient grounds to open a formal probe into whether Telegram’s compliance with the specific CSAM-related duties under the Act has been adequate.
The tension at the heart of the Telegram case is one that has defined debates about the platform for years. Telegram’s architecture is divided: public channels and groups are more accessible to outside detection tools, but the platform’s encrypted private messaging, the feature that has made it popular with activists, journalists, and dissidents in authoritarian states, creates a structural limit on what content moderation is possible.
The NSPCC, in responding to Telegram’s IWF partnership in December 2024, noted the distinction directly: welcoming the step on public content while arguing that “there should be no part of the service where perpetrators can act without detection.”
The Online Safety Act’s provisions on end-to-end encrypted messaging remain the most contested part of the regime, with Signal having previously warned it would withdraw from the UK if forced to scan private messages.
Ofcom has signalled it is not currently minded to mandate client-side scanning.
The investigation comes in a period of sustained regulatory pressure on messaging and social media platforms across the UK.
Ofcom has now opened investigations into nearly 100 services since the Online Safety Act came into force in 2025, issued nearly a dozen fines, and in March 2026 wrote directly to six of the largest platforms, Facebook, Instagram, Roblox, Snapchat, TikTok, and YouTube, demanding evidence of further child safety improvements by 30 April.
The Telegram probe adds a major messaging platform to an enforcement list that, to date, has concentrated more heavily on pornography sites and niche image boards.
Telegram did not immediately respond to a request for comment at the time of the Reuters report. Ofcom has said it will provide updates on the investigation as soon as possible.
