Artifact GuideUKIllegal Content Risk Assessment

UK Online Safety Act Illegal Content Risk Assessment

Every regulated Part 3 user-to-user and search service must keep a suitable and sufficient illegal content risk assessment for the service.

This guide explains what to assess, the different user-to-user and search tests, timing, review triggers, and the evidence that connects findings to controls.

Author
Sorena AI
Published
May 9, 2026
Updated
Jul 24, 2026
Questions
3

Structured answer sets in this page tree.

Primary sources
6

Cited legal and guidance references.

Publication metadata
Sorena AI
Published May 9, 2026
Updated Jul 24, 2026
Overview

An is a service-specific analysis of how users may encounter illegal content and, for user-to-user services, how the service may be used to commit or facilitate priority offences. It must cover the Act's required elements, use Ofcom's risk profiles, and drive proportionate safety measures. A generic policy or list of offences is not enough.

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3 of 3 questions
Question 1

What must the assessment cover?

User-to-user providers assess the risk of users encountering each kind of and other illegal content, and the risk of the service being used to commit or facilitate a priority offence. Search providers assess the risk of users encountering priority illegal content and other illegal content in or via search results. Sections 9 and 26 set the detailed elements for each service type.

The assessment must consider the service's user base, functionalities, algorithmic systems, business model, governance, proactive technology, user tools, intended and unintended uses, and how easily, quickly, and widely content may spread. It must also consider Ofcom's current risk profiles. Rate likelihood and impact using evidence that reflects the actual service.

  • Define each assessed service and part, provider entity, user groups, languages, geography, features, algorithms, and revenue model.
  • Assess every statutory kind of ; do not limit the work to content already found on the service.
  • Record evidence, assumptions, risk level, existing controls, gaps, owner, and the proportionate measure chosen for each material risk.
Citations
Online Safety Act 2023

Sets the illegal content risk assessment duties and required elements for regulated user-to-user services.

Question 2

When is it due and when must it be reviewed?

Services already in scope had to complete the first assessment by 16 March 2025. A new user-to-user or search service, or an existing service that newly comes into scope, must complete it within three months of starting or changing the service.

The provider must take appropriate steps to keep the assessment up to date. Complete a new assessment before a significant change to the service's design or operation. Review sooner when Ofcom significantly changes a relevant risk profile or when incidents, complaints, enforcement, research, or performance data show that the current risk picture may be wrong. Ofcom recommends review at least every 12 months.

  • Put the annual review and every known product-change gate into the release calendar.
  • Version the assessment and preserve the evidence and approval behind each changed risk rating.
  • Treat new priority offences and changes to Ofcom risk profiles as legal-review triggers, not background reading.
Citations
Question 3

What must happen after the assessment?

The assessment is an input to the illegal-content safety duties. User-to-user providers need proportionate systems and processes designed to prevent users encountering , mitigate identified harm and offence risks, minimise how long priority illegal content remains, swiftly take down illegal content when aware of it, and effectively mitigate and manage the risk that the service is used to commit or facilitate priority offences. Search providers must use proportionate systems and processes to minimise encounter risk in or via search results and manage assessed risks.

Providers may follow applicable measures in Ofcom's or use alternative measures that meet the legal duties. Keep the assessment record, the code mapping or alternative-measure rationale, implementation evidence, tests, terms or public statement, content-reporting route, complaints procedure, and review record. Ofcom can request these records.

  • Assign every mitigation to a product, moderation, engineering, policy, or governance owner with a due date and acceptance test.
  • Make terms and public statements match the systems actually deployed and apply the stated rules consistently.
  • Test reporting and complaints journeys, including access by children and people who need assistance where the Act requires it.
Citations
Primary sources

References and citations

legislation.gov.uk
Referenced sections
  • Sets the illegal content risk assessment duties and required elements for regulated user-to-user services.
legislation.gov.uk
Referenced sections
  • Sets the corresponding duties and required elements for regulated search services.
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