Home Office Statistics Reveal Increase in Terrorist-Related Arrests 

• It is almost certain that the increase in terrorism related arrests indicates that terrorism will remain a significant threat to the UK. In February 2022, the UK terrorism threat level was lowered from SEVERE (an attack is highly likely) to SUBSTANTIAL (an attack is likely) and has remained at that level since then {2}. Based on current trends and international factors increasing global tensions (for example the Israel/Hamas war, instability in the Middle East and the war in Ukraine), it is highly unlikely that the threat level to the UK from terrorism will decrease in the short to medium term.  

• It is highly likely Extreme Islamist Terrorism will remain the predominant terrorist threat to the UK and makes up the majority of terrorism related prisoners in the previous year. Figures published by the Home Office in September 2023 indicated that operations to counter Extreme Islamist Terrorism accounted for approximately three quarters of MI5’s case work between 2018 and 2023 {3}. 

• It is highly likely that Extreme Right-Wing terrorism will continue to be a significant terrorist threat and it is highly likely that this threat to the UK will increase in the long term, likely resulting in more arrests of Extreme Right-Wing terrorists.  

• While making up the smallest of the three ideological categories of prisoners in the UK, it is likely that increase in prisoners aligned to ideologies other than Extreme Islamist terrorism and Extreme Right-Wing terrorism indicates that the threat from individuals aligned to Left-Wing, Anarchist and Single-Issue Terrorism (LASIT), as well as other fringe terrorist ideologies, will continue to grow in the long term.  

• It is highly likely that the rise in minors being arrested for terrorism offences indicates there will continue to be an increase in individuals under the age of 18 attracted to extremist ideologies, either through grooming by adult members of terrorist groups, or through self-radicalisation by accessing extremist materials online. Speaking to Pool Re Solutions for the Totally Terrorism podcast, Dr Joe Whittaker, senior lecturer in Criminology, Sociology, and Social Policy at Swansea University, highlighted that while there have been recent successes by governments to crackdown on the spread of terrorist materials online, this has driven terrorist groups to use more secure and less mainstream platforms to spread propaganda and instructional information, creating harder to find but more resilient online terrorist networks {4}. 

• Of those arrested for terrorism offences, 11 of them were convicted of non-terrorism related offences. It is a realistic possibility that this indicates individuals suspected of involvement in terrorist related activity may also be involved in non-terrorism related criminal activity. It is also likely that this demonstrates the high bar UK authorities need to reach to convict an individual of a terrorism offence.  

• While terrorist groups may aspire to conduct complex attacks in the UK (for example using an Improvised Explosive Device (IED) to cause economic and symbolic damage to a building or organisation, as well as to cause loss of life) it is likely that the challenges in planning and conducting a complex terrorist attack act as a significant barrier and allow more opportunities for the UK security services to identify and disrupt such attacks.  

• It is highly likely that a terrorist attack at this time would be conducted by an individual or small cell using a low-sophistication methodology. E.g., Bladed or Blunt Force Weapons, Vehicle as a Weapon, Fire as a Weapon. While the target of an attack by any terrorist will be determined by a number of factors (for example ideology, perceived grievances, mental health issues, etc) it is likely that a terrorist attack in the UK would seek to target members of the public in densely populated publicly accessible areas.  

Intelligence Cut-Off Date: 18 June 2024