UK OSA Section 59 with Schedules 5, 6 and 7 - Priority illegal content: the priority offence categories
Services must proactively address priority categories of illegal content including CSAM, terrorism, fraud, drugs, weapons, immigration offences, and sexual exploitation
Where this comes from
Provision: Section 59 with Schedules 5, 6 and 7 - Priority illegal content: the priority offence categories
Instrument: UK Online Safety Act 2023
Citation: Online Safety Act 2023, c. 50, s 59(7) and s 59(10) (meaning of priority offence and priority illegal content); Sch 5 (terrorism offences), Sch 6 (child sexual exploitation and abuse offences), Sch 7 (other priority offences); s 10(2)-(3) (the duties these categories feed)
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 The as-enacted text is superseded.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
User-to-user content surface — any one of these:
- Service allows user-generated content
- Service enables direct messaging between users
What engineering work it implies
Sample acceptance criteria Landfall generates for this obligation:
- Proactive systems address each priority category (CSEA, terrorism, fraud, drugs, weapons, immigration, sexual exploitation)
- Known CSEA/terrorist media is matched against hash/URL lists and blocked at or before upload
- Detected priority illegal content is removed swiftly and, where required, reported to the relevant authority
- Detection coverage and outcomes per category are recorded for transparency reporting
- System handles null/empty input gracefully (no 500 errors)
Questions people ask
- Does UK OSA Section 59 with Schedules 5, 6 and 7 - Priority illegal content: the p… apply to my service?
- It applies when at least one of: Service allows user-generated content; Service enables direct messaging between users.
- From when does this apply?
- UK OSA Section 59 with Schedules 5, 6 and 7 - Priority illegal content: the p… applies from 26 October 2023. Its current status is: in force.
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.