UK OSA Section 12(3)(a) - Safety duties protecting children: preventing children of any age from encountering primary priori…
Operate proportionate systems to prevent children of any age from encountering primary priority harmful content including pornography, self-harm, suicide, and eating disorder content
Where this comes from
Provision: Section 12(3)(a) - Safety duties protecting children: preventing children of any age from encountering primary priority content
Instrument: UK Online Safety Act 2023
Citation: Online Safety Act 2023, c. 50, s 12(3)(a) with s 12(4)-(6) (age verification or age estimation; highly effective standard) and s 12(5) (terms-of-service exception); s 61 (primary priority content that is harmful to children); s 13(5)-(6) (extent)
Text version: Online Safety Act 2023 c. 50, revised text as displayed on legislation.gov.uk on 2026-09-21 ('up to date with all changes known to be in force on or before 21 September 2026'), including the amendments made by the Crime and Policing Act 2026 in force from 29 June 2026 (S.I. 2026/689) and s 66 in force from 7 April 2026 (S.I. 2026/262). The as-enacted text is superseded.
Who it applies to
Child audience (designed for OR likely accessed by children) — any one of these:
- Service is specifically designed for children under 18
- Service is likely to be accessed by children under 18
Remaining applicability scope — all of these:
- Service allows user-generated content
- Youngest user age is Under 13 or 13-15
Scope in the source's own terms
- User-to-user service or search service
- Service available in the United Kingdom
What engineering work it implies
Sample acceptance criteria Landfall generates for this obligation:
- Age gate appears before accessing age-restricted content/features
- DOB input uses dropdowns (not free text) to reduce typos
- System calculates age from DOB, not from user-entered age
- Age is stored and doesn't need to be re-entered on each visit
- Age verification cannot be bypassed by direct URL access
Evidence an auditor expects
- Assessment documentDocument review
Risk assessment for illegal content
Assessment of risks of illegal content appearing on service with mitigation measures
- Technical controlTechnical audit
Content moderation systems
Technical measures to identify and remove illegal content
Questions people ask
- Does UK OSA Section 12(3)(a) - Safety duties protecting children: preventing child… apply to my service?
- It applies when at least one of: Service is specifically designed for children under 18; Service is likely to be accessed by children under 18; and Service allows user-generated content; Youngest user age is Under 13 or 13-15.
- From when does this apply?
- UK OSA Section 12(3)(a) - Safety duties protecting children: preventing child… applies from 10 January 2024. Its current status is: in force.
- What evidence does an auditor expect?
- Risk assessment for illegal content; Content moderation systems.
Find out whether this one lands on you
Landfall's pre-scan answers the applicability question above for your product in minutes, then turns every obligation that applies into traceable engineering tickets with a citation chain your auditors can follow.
Not legal advice. Landfall maps regulatory obligations to engineering work for planning purposes. Its verdicts are not legal advice and create no attorney-client relationship — verify with qualified counsel before relying on them.