Question to the Ministry of Justice:

To ask the Secretary of State for Justice, what proportion of terrorism-related prisoners in the UK are linked to Islamist ideology.

Information about individuals convicted or in custody for terrorism and terrorism-connected offences, by ideology, is published by the Home Office as part of the ‘Operation of police powers under the Terrorism Act 2000’ statistics series. The series can be accessed via the following link: https://www.gov.uk/government/collections/operation-of-police-powers-under-the-terrorism-act-2000.

The numbers held in custody are shown on table P.01 of the annual and quarterly tables. As of 31 March 2025 (the most recent data available), 61% of terrorist prisoners were categorised as holding Islamist Extremist views.

Given the sensitive nature of the information, further breakdowns are not published as they may undermine our national security efforts.

Data on all terrorism-related offences is in the published series but not disaggregated by ideology. Table C.03 gives details on the numbers convicted for terrorism-related offences. Information on sentence length is included in table C.04, and the number released by sentence length is provided in table P.05.

All terrorists are managed through a specialist, multi-agency case management process, which includes regular risk assessments and rehabilitative tools to identify, assess and manage an offender’s terrorist risk and needs, including any clear links to an extremist ideology. We have a range of interventions to address and reduce the drivers of radicalisation and move offenders away from harmful ideologies. Our interventions are carried out by qualified staff who receive specialist training. The tracking of religion relies on prisoners’ self-declaration.