Almost half of all terrorism arrests in Great Britain since the 9/11 attacks on the twin towers in 2001 have come in the past year, official data shows.
There have been 6,539 arrests for terror-related activity in Great Britain since the 2001 attacks and 3,021 of those arrests were in the year ending 31 March 2026, according to the Home Office.
The increase coincides with the proscription of Palestine Action, which came into effect on 5 July last year and has led to thousands of arrests of people for allegedly supporting the direct action protest group, the first such group to be banned under the Terrorism Act.
The ban, which has been criticised by UN experts, NGOs, a former director of public prosecutions and a former director of the security services, is the subject of a continuing legal challenge, which will next be heard at the UK supreme court on 4 November.
Ruth Ehrlich, the director of external relations at Liberty, which intervened in the legal challenge, said: “The staggering increase in arrests over the past year is the clearest indicator that the UK’s counter-terror laws are not fit for purpose.
“The government’s current definition of terrorism is so wide-ranging it captures behaviour most people would never consider terrorism. When it’s not clear what counts as terrorism, public trust collapses and without trust, counter-terror laws simply won’t work.
“This data underscores the urgent need to update the current definition of terrorism to enable current and future governments to uphold their duty to safeguard the public whilst protecting people’s rights and preventing overreach.”
The proscription led to a mass civil disobedience campaign with most of those arrested at demonstrations organised by Defend Our Juries (DOJ), where they held up placards saying: “I oppose genocide, I support Palestine Action.”
Terrorism-related arrests were up 1,434% in the year ending 31 March compared with the previous 12 months. There was also a 3,761% increase in women and girls arrested and a 2,306% increase in arrests of those aged 30 and over. Earlier, this year, Raj Chada, the head of criminal defence at the law firm Hodge Jones and Allen, said: “The most common terrorist in the UK at present is a pensioner at a silent vigil holding a placard.”
DOJ says the number of arrests relating to support for Palestine Action, which targets UK entities it claims to be complicit in Israeli genocide against Palestinians, has since risen to more than 3,600, which would be over half of the arrests since 9/11.
About 2,500 people have been charged under section 13 of the Terrorism Act, which prohibits showing support for a terrorism group and carries a maximum sentence of six months in prison. DOJ says at least 50 people have been charged under section 12, which concerns inviting support for a banned group, must be heard by a jury and carries a maximum sentence of 14 years.
A DOJ spokesperson said: “These shocking statistics expose the true nature of how the British government uses terror laws. Since July 2025, thousands of peaceful protesters have been arrested under the Terrorism Act for quietly expressing opposition to genocide and standing with those who have taken direct action against it. By doing this, the government has shown that they are not using these laws to protect the public – rather to silence those who speak and act against genocide.”
In June, four Palestine Action activists became the first defendants convicted of property damage whose offending – during a 2024 raid on a factory near Bristol owned by the Israeli weapons manufacturer Elbit – was deemed by a judge post-conviction to have a “terrorist connection”.
A Home Office spokesperson said: “Showing support for a proscribed organisation is against the law. Decisions to arrest are operational matters for the police and are taken on the basis of the facts and circumstances of each case.”
