Most people, when asked what terrorism is, will say that it is the use of violence and terror to create fear among people. This is broadly the dictionary definition. The 2017 Manchester Arena bombing at an Ariana Grande concert, in which 22 people, including many children, were killed, is a clear example.
Yet the legal definition of terrorism in Britain is far broader than this common understanding. Section 1 of the Terrorism Act 2000 allows even “damage to property” to constitute terrorism when it is carried out for a political, religious, racial or ideological purpose and is intended to influence the government or intimidate the public. Where firearms or explosives are involved, the latter requirement does not apply.
Including politically motivated damage to property within the definition was controversial from the start. When Parliament debated the bill in 1999, animal liberation activists were among the groups MPs had in mind.
Labour MP Alan Simpson warned during the debate that by defining attacks on property as terrorism, “we transform the relationship between civil protest movements and elected Parliaments and the judicial system.”
The criticism did not end with Parliament. The Supreme Court later described Section 1’s definition of terrorism as “very far-reaching”, while David Anderson QC, the independent reviewer of terrorism legislation, called it “remarkably broad – absurdly so in some cases”.
In his 2012 report, Anderson observed:
“The current law allows members of any nationalist or separatist group to be turned into terrorists by virtue of their participation in a lawful armed conflict… however odious the regime which they have attacked.”
In his 2014 Terrorism Report, he warned:
“To render people subject to the terrorism laws whom no sensible person would think of as terrorists risks destroying the trust upon which these special powers depend for their acceptance by the public.”
Yet defining what can count as terrorism is only part of the story. Not every organisation whose conduct falls within that definition is proscribed. That decision rests with the government.
Proscription therefore adds a political choice: Which organisations should be banned, making membership and inviting support for them criminal offences.
For example, the Kurdistan Workers’ Party (PKK), an armed Kurdish group that has fought the Turkish state for decades, is proscribed in Britain. Its Syrian offshoot, the Democratic Union Party (PYD), is not, because PYD-led forces became Western allies in the fight against ISIS (ISIL).
Britain proscribed Hamas’s military wing in 2001. In 2021, Home Secretary Priti Patel extended that proscription to Hamas in its entirety, including its political wing, declaring the previous distinction between the two “artificial”. Many civilian members of Hamas who had never picked up a gun were now deemed terrorists alongside its fighters.
By collapsing the distinction between Hamas’s military and political wings, Britain legitimised Israel’s portrayal of Hamas’s civilian administration as part of a terrorist apparatus and, with it, the targeting of hospitals and schools as terrorist infrastructure.
The asymmetry is stark. Britain’s terrorism laws can criminalise non-state organisations and those who support them, while state terrorism, including Israel’s, remains outside their reach.
The proscription of Palestine Action brought a different consequence of these laws into focus: Their use against protest in Britain. Palestine Action is a British direct-action group that has targeted arms companies supplying Israel. In July 2025, the government proscribed it under the Terrorism Act 2000.
United Nations Human Rights Chief Volker Turk warned that the decision to proscribe Palestine Action “raises serious concerns that counter-terrorism laws are being applied to conduct that is not terrorist”.
The ban has been fiercely contested in the courts. In February 2026, the Divisional Court ruled the proscription unlawful. On June 15, the Court of Appeal reversed that decision and upheld the ban. The court also described Elbit as carrying out a “lawful business”, ignoring its role in supplying the Israeli military during the genocide.
In upholding the ban, Lady Chief Justice Sue Carr drew a contrast with the Suffragettes, saying Palestine Action was not “a direct action civil disobedience protest group like the Suffragettes operating transparently in the open” but “a covert group operating in cells”.
Carr’s characterisation rests on an extraordinarily sanitised version of suffragette history.
In November 1909, a suffragette attacked Winston Churchill with a horse whip. In the same month, suffragettes, armed with a catapult and missiles, attacked Prime Minister H. H. Asquith’s car in Liverpool.
In 1912, Suffragettes attempted to set fire to the Theatre Royal in Dublin during a matinee attended by Asquith. They left a canister of gunpowder close to the stage. Earlier in the day, Mary Leigh had hurled a hatchet towards Asquith.
In 1913, four postmen in Dundee were severely injured by phosphorus chemicals left in post boxes. The following year, Mary Richardson slashed the Rokeby Venus in the National Gallery, while bombs were discovered in St Paul’s and churches were burned down.
This history sits uneasily with Carr’s distinction. The Suffragettes themselves engaged in politically motivated attacks on property and people of precisely the kind that Britain’s modern definition of terrorism is broad enough to capture.
The Filton case shows what this can mean in practice. When the Filton 25 attacked an Elbit factory in Bristol, they were remanded in custody for up to 18 months. When six of them went on trial in November 2025, the jury acquitted them of aggravated burglary, the most serious charge, and failed to reach verdicts on criminal damage. No defendant was convicted at that first trial. At a retrial, four were convicted of criminal damage; only one was eventually convicted of grievous bodily harm, without intent.
The jury was not told that guilty verdicts could later lead to the offences being treated as having a “terrorist connection” for sentencing. Justice Jeremy Johnson subsequently made precisely that finding. Johnson had also ruled out defences based on necessity and the need to prevent the greater crime of genocide. In doing so, he usurped the role of the jury.
The consequences of the ban were not confined to those accused of taking direct action against Elbit. Once Palestine Action was proscribed, inviting or expressing support for the group became a terrorism offence.
When the government proscribed Palestine Action, people defied the ban. Nearly 4,000 people have been arrested for holding placards supporting Palestine Action.
The Home Office reported that in the year ending March 2026, there were 3,061 terrorism-related arrests, 2,819 of them linked to suspected support for Palestine Action. The average age of those arrested in connection with Palestine Action was 59, compared with 31 for all other terrorism-related arrests. A majority of the Palestine Action arrests were women.
The profile of Britain’s average “terrorist” changed from a man aged 31 to a woman aged 59.
This is where Britain’s extraordinarily broad definition of terrorism, combined with the government’s power to proscribe organisations, has led. Conduct once understood as protest and political expression can now be prosecuted under terrorism legislation.
As Orwell wrote, “If thought corrupts language, language can also corrupt thought.” When the meaning of “terrorism” is stretched far enough, the extraordinary powers attached to that word stretch with it.
Today, my own trial begins. I am accused of inviting support for Hamas. My prosecution is not separate from the story told here. It is where that story leads.
The views expressed in this article are the author’s own and do not necessarily reflect Al Jazeera’s editorial stance.
