On 20 June 2025 the Home Secretary (at the time, Yvette Cooper) made a decision to proscribe the organisation Palestine Action (PA) under counter-terrorism legislation. On 13 February 2026, the Divisional Court (Sharp P, Swift and Steyn JJ) ruled that the Home Secretary’s decision was unlawful. The case is R (Ammori) v Secretary of State for the Home Department [2026] EWHC 292 (Admin), [2026] WLR(D) 104.

A brief history of proscription law

The word “proscription” in the sense of “dooming to destruction” (Dr Johnson’s 18th century definition) comes from the dying decades of the Roman Republic. In 82 BCE, Sulla drew up a list of hundreds of his enemies among the social elite and, having obtained the approval of the non-elite’s assembled representatives, posted it up with rewards offered for heads. The turbulent decades which followed were important for the maturation of Roman law, as Aldo Schiavone demonstrates in The Invention of Law in the West. Tellingly, some of the most famous lawyers of the period, struggling for more order amid the upheavals, were themselves victims of political violence, perhaps most famously Cicero, killed under the proscription of the Second Triumvirate (Octavian, Marc Antony and Lepidus) in 43 BCE.

Medieval English law had notions of outlawry and attainting: putting someone’s life and belongings beyond the protection of the law. In early modern times, we find the term “proscription” being used, not in English law as such, but to describe such cases. For example, Spenser writing in the late 1500s is quoted by Johnson in his dictionary in the 1700s as using the word to describe the fate of Robert de Vere, earl of Oxford, who in the late 1300s had been banished from the country and his property confiscated.  A little later, we find Logan in the 1840s using the word to describe the outlawing of certain Scottish clans in the 1600s (“…although suffering from a proscription so severe, [the clan] took the field…”) and then the disarming of the clans and the prohibition of arms to them after Culloden in 1746. Millet in the 1850s used the term “proscribed royalist” to refer to a romantically-depicted adherent of Charles II on the run in the mid 1600s.

“Proscription” in the modern UK legal sense involves banning organisations with a view to eliminating them. The general pattern is to criminalise associating with or supporting proscribed organisations.

During the period of warfare and revolutionary sentiment in 1799, an act was passed for the banning of radical political organisations in Great Britain. And even though it was enforced less fiercely as the decades went by, and mostly repealed seventy years later, similar laws were passed from time to time to suppress undesired organisations in colonies. An example is the Indian Criminal Law Amendment Act 1908, introduced in response to bombings and assassinations as part of the struggle against British rule. Part II of this Act empowered the Governor General in Council to proscribe an association “which encourages or aids persons to commit acts of violence or of which the members habitually commit such acts,” if satisfied that it interfered with the administration of the law or the maintenance or law and order, or constituted a danger to the public peace. Sentences of up to three years’ imprisonment for involvement in such associations were introduced.

By the late 20th century, though, such laws were limited on the British mainland. The Public Order Act 1936, originally targeting the BUF, still applied to suppress quasi-military / -police organisations but the Prevention of Violence (Temporary Provisions) Act 1939, originally targeting a major IRA bombing campaign commenced in 1938, had been allowed to expire in 1953.

This changed in 1974, with the passage of the Prevention of Terrorism (Temporary Provisions) Act. Section 1(3) empowered the Home Secretary to proscribe “any organisation that appears to him to be concerned in terrorism occurring in the United Kingdom and connected with Northern Irish affairs, or in promoting or encouraging it.” At that time, “terrorism” was narrowly defined as “the use of violence for political ends, and includes any use of violence for the purpose of putting the public or any section of the public in fear” (section 9(1)).

In a review of terrorism legislation in 1996, Lord Lloyd of Berwick, a senior judge, recommended that “terrorism” be defined more widely by extending it (so far as relevant to the PA case) to

• What he called “violence against property” as well as people. He took inspiration in this regard from the operational definition of terrorism used by the US Federal Bureau of Investigation.
• Terrorism not involving a Northern Irish element.

The Lloyd report came at the tail-end of an 18 year period of Conservative government. In 1998, the new (and New) Labour government published a consultation paper. This expressed the intention to extend the definition to cover serious property damage, but expressed uncertainty about whether to extend proscription (and other) powers to domestic terrorism. The paper noted that:

• The only domestic terrorism incidents of the last 25 years had come from “militant animal rights activists and to a lesser extent from Scottish and Welsh nationalist extremists” and “environmental rights activists.” The use of violence against people (e.g. letter bombs) had diminished in recent years, though there had been recent property damage (for example, in attacks on labs). But there was a possibility of US-style violent anti-abortion or other activism emerging in the UK and “threatening serious violence to people and property here.” Arguments for extending proscription included delegitimisation (considered to have been successful in Northern Ireland) and obstruction of fund-raising.
• On the other hand, it noted that fund-raising restrictions can be circumvented, that it could be impractical to monitor a potentially very large list of groups. There was also a risk of politicisation: “the Government might be exposed to pressure to target organisations that it might not regard as terrorist.”

The arguments were said by the Government to be “finely-balanced.” But in the event, it decided to extend the scope. A new Terrorism Act was passed in 2000.

The statutory provisions

Section 3 of the 2000 Act builds on the language of the 1974 Act by giving the Home Secretary the power, but not the duty, to proscribe an organisation if she “believes that it is concerned in terrorism.” It is accepted that the belief must be reasonable (para 42 of the recent judgment).

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