Proscription

Once a group is banned, membership, inviting support, or even displaying a symbol of support becomes a criminal offence.

The rule

Once an organisation is proscribed, it is an offence to belong or profess to belong to it (section 11), to invite support for it (section 12(1)), or to express an opinion or belief supportive of it while reckless as to whether others will be encouraged to support it (section 12(1A)). It is also an offence to wear or display an article, or publish an image of one, in circumstances that arouse reasonable suspicion of membership or support (section 13).

The nuance

The offences are about support for the organisation. Reporting that something happened, quoting words as evidence of an event, or criticising the law that bans a group is not, by itself, an opinion supportive of that group. Where the line falls in a particular case is for a court.

The test in section 12(1A) is recklessness, not intent. A person can commit the offence without meaning to encourage anyone, if they are reckless as to whether their audience will be encouraged.

Both section 12(1A) and the image offence in section 13(1A) were added in 2019. Before then, expressing a supportive opinion was an offence only if it invited support.

The offences apply only while an organisation is proscribed. Check the current list on GOV.UK, not a secondary source.

Why it matters

Proscription turns ordinary acts of expression, such as a sign, a T-shirt or a post, into potential terrorism offences. It applies to everyone, not just members.

History

1. 2000The Terrorism Act 2000 creates the membership, support and uniform offences.
   Sources: Terrorism Act 2000, section 11 — Membership · Terrorism Act 2000, section 12 — Support · Terrorism Act 2000, section 13 — Uniform and publication of images
2. 2019The Counter-Terrorism and Border Security Act 2019 adds the reckless-expression offence and the image-publication offence.
   Sources: Counter-Terrorism and Border Security Act 2019, section 1 — Expressions of support for a proscribed organisation · Counter-Terrorism and Border Security Act 2019, section 2 — Publication of images and seizure of articles
3. JUL 2025Palestine Action, Maniacs Murder Cult and Russian Imperial Movement are added to the proscribed list.
   Sources: The Terrorism Act 2000 (Proscribed Organisations) (Amendment) Order 2025
4. FEB 2026The High Court proposes to quash the Palestine Action proscription.
   Sources: R (Ammori) v Secretary of State for the Home Department [2026] EWHC 292 (Admin)
5. JUN 2026The Court of Appeal allows the Home Secretary's appeal; the proscription stands.
   Sources: Secretary of State for the Home Department v R (Ammori) [2026] EWCA Civ 721

Primary sources

• Terrorism Act 2000, section 11 — Membership — Offence of belonging, or professing to belong, to a proscribed organisation.
• Terrorism Act 2000, section 12 — Support — Offences of inviting support for a proscribed organisation and (s.12(1A)) expressing an opinion or belief supportive of one while reckless as to whether others will be encouraged to support it.
• Terrorism Act 2000, section 13 — Uniform and publication of images — Offences of wearing or displaying articles, or (s.13(1A)) publishing an image of clothing or an article, in circumstances arousing reasonable suspicion of membership or support of a proscribed organisation.
• Proscribed terrorist groups or organisations — The government's current list of proscribed organisations with the stated reasons for each proscription. Check this before relying on any other list.

In the timeline

• JUL 2025 — A protest group is proscribed as a terrorist organisation
• 2025 → — Mass arrests for holding a sign
• JUN 2026 — Court of Appeal: the ban stands

Not legal advice. Laws change; check the primary sources and speak to a lawyer about your own situation.

Checked 2026-10-14 · JSON · source file · change history