A record 275 people were held in custody for terrorism and terrorism-connected offences in Great Britain at the end of June, up from 273 in March and approximately seven per cent more than a year earlier, according to the latest Home Office figures.
The series counts people held for terrorism and terrorism-connected offences. It includes convicted prisoners and people held on remand, and does not mean that all 275 have been convicted of a terrorist offence. The total is the highest since the series began in 2010, when it stood at 126, although changes to the statistical definition in September 2020 limit direct comparisons with earlier years.
Of those in custody, 157 (57 per cent) were categorised as holding Islamist-extremist views and 80 (29 per cent) as holding extreme right-wing views. A further 38 (14 per cent) fell into other ideological categories. The number classified as holding Islamist-extremist views remained unchanged at 157 compared with June 2025.
The record prison population coincides with an unprecedented rise in terrorism-related arrests, driven overwhelmingly by arrests linked to the Government’s proscription of Palestine Action.
The same figures show that police made 3,867 terrorism-related arrests in the year to June 2026, an unprecedented annual total. Of those, 3,630, or approximately 94 per cent, were connected with suspected support for the proscribed group. In the year ending June 2025, the equivalent total was 234. Excluding Palestine Action-related arrests, the figure for the year to June 2026 was approximately 237, close to the level recorded across the preceding decade. The two annual figures use comparable definitions, though some cases are reclassified as investigations progress.
An arrest is not evidence of guilt. Of the 3,867 arrests in the year, 704 had resulted in a charge at the time the figures were compiled, about 18 per cent. Of the 3,630 arrests linked to Palestine Action, 632 had led to charges, approximately 17 per cent. The overwhelming majority of those charges, 621, were brought under section 13 of the Terrorism Act 2000, with eight under section 12 and three under section 57. Those not charged were released under investigation or on bail, released without charge, or recorded under other outcomes, with some cases still unresolved.
The offences carry very different penalties. Section 13, which covers wearing or displaying an item in circumstances that arouse reasonable suspicion of support for a proscribed organisation, is tried summarily and carries a maximum of six months (Terrorism Act 2000, section 13). Section 12, which covers inviting or expressing support, carries up to 14 years on indictment (section 12), and section 57, possession of an article for terrorist purposes, up to 15 years (section 57). The vast majority of Palestine Action-related charges were brought under section 13, which carries a substantially lower maximum sentence than sections 12 and 57.
Palestine Action was announced for proscription on 23 June 2025 and the order took effect on 5 July, making it the first direct action protest group banned under terrorism legislation. The power to proscribe rests on section 3 of the Terrorism Act 2000, which allows the Home Secretary to add an organisation to Schedule 2 if satisfied it is concerned in terrorism.
The ban is subject to an ongoing challenge from the group’s co-founder, Huda Ammori. In February the Divisional Court found the proscription unlawful on two grounds, holding that the Home Secretary’s reasoning was inconsistent with her own policy and that the ban was incompatible with articles 10 and 11 of the European Convention on Human Rights. The Court of Appeal disagreed in June and allowed the Home Secretary’s appeal, concluding that the decision was a proportionate interference with those rights. Ammori now appeals to the Supreme Court, which has listed the hearing for 4 and 5 November (Ammori v Secretary of State for the Home Department). The court granted permission on one ground only, so not every issue examined by the lower courts is before it. The ban remains in force pending the outcome.
The proscription has drawn criticism from across politics. Earlier this month the former cabinet minister Sir Jacob Rees-Mogg told the American broadcaster Tucker Carlson that banning the group had “made the government look stupid” (interview transcript).
“We have historically protected freedom of speech and we are now attacking freedom of speech, and I’m deeply concerned about that,” Rees-Mogg said. “I’m very against banning things. I would never ban things. I’m not in favour of the way free speech is being policed in this country.”
He argued that ministers had confused the group’s political supporters with people who want to commit violence, adding that it was wrong to arrest people over a political view while it was reasonable to arrest those who “propose and prepare acts of terrorism”.
Separate figures show that 52 terrorist prisoners were released in the year ending March 2026 (Home Office release, year ending March 2026). Terrorism offenders are excluded from the general early-release scheme introduced to ease prison overcrowding. Their eligibility for release is governed by separate rules, depending on the offence and the sentence imposed.
The custody figures and the arrest figures measure different things. The prison count records the people held in the terrorism-related category, convicted and on remand. The arrest figures record people detained on suspicion, most of whom had not been charged at the time of reporting. There is no official evidence that the arrests of the past year account for the record prison population, in which those classified as holding Islamist-extremist views form the majority.
Great British PAC reaction
Claire Bullivant, chief executive of Great British PAC, said:
“These figures are a sobering reminder of the serious threats Britain continues to face. A record 275 people are being held for terrorism and terrorism-connected offences, with 57 per cent classified as holding Islamist-extremist views.
“Let us be absolutely clear, Islamist extremism is a dangerous ideology that has no place in our country. The overwhelming majority of British Muslims want to see extremism tackled too. They have no connection with these extremist ideologies and deserve the same protection from terrorism as every other British citizen.
“But we must never allow political correctness or fear of causing offence to stand in the way of protecting the public. Our police and security services must have the powers, resources and confidence to confront extremism wherever it exists, without fear or favour.
“Labour must demonstrate that it understands the gravity of the threat and is prepared to confront it. National security is not an exercise in political correctness, it is the first duty of government.
“The British people do not expect their government to be timid in the face of extremism. They expect it to be resolute. And they are absolutely right.”
