Online Safety Act in force: platforms must start tackling illegal material from 17 March 2025

March 19, 2025

As of 17 March, online platforms must start putting in place measures to comply with the duties to p[revent illegal harms under the Online Safety Act.  Ofcom has launched its latest enforcement programme to assess industry compliance.

Providers of services in scope of the OSA had until 16 March to carry out a suitable and sufficient illegal harms risk assessment, to understand how likely it is that users could encounter illegal content on their service, or, in the case of “user-to-user” services, how they could be used to commit or facilitate certain criminal offences.

From 17 March, the next set of illegal harms duties have come into force. Therefore, platforms must start implementing appropriate measures to remove illegal material quickly when they become aware of it, and to reduce the risk of “priority” criminal content from appearing in the first place.

Ofcom will be assessing platforms’ compliance with their new illegal harms obligations under the OSA, and launching targeted enforcement action where it uncovers concerns.

Ofcom will also initially prioritise the compliance of sites and apps that may present particular risks of harm from illegal content due to their size or nature, for example because they have a large number of users in the UK, or because their users may risk encountering some of the most harmful forms of online content and conduct

Given the acute harm caused by the spread of online child sexual abuse material (CSAM), assessing providers’ compliance with their safety duties in this area has been identified as one of its early priorities for enforcement. Ofcom’s evidence shows that file-sharing and file-storage services are particularly susceptible to being used for the sharing of image-based CSAM.  It is now assessing the safety measures being taken, or that will soon be taken, by file-sharing and file-storage providers to prevent offenders from disseminating CSAM on their services.

Ofcom has written to a number of these services to put them on notice that it will shortly be sending them formal information requests regarding the measures they have in place, or will soon have in place, to tackle CSAM, and requiring them to submit their illegal harms risk assessments to us.  It highlights its investigatory and enforcement powers including the ability to levy hefty fines if organisations do not comply.

Ofcom expects to make additional announcements on formal enforcement action over the coming weeks.