What is CBRN Terrorism?
This is the terrorist use (or threatened use) of Chemical, Biological, Radiological or Nuclear material as a weapon, with the intention to cause harm. This encompasses a wide range of agents and materials including corrosive substances, poisons, toxins, biological organisms and radioactive sources. These materials can be harmful to humans in a variety of ways when inhaled, ingested or absorbed.
Headline Assessment
-
Of the multiple CBRN methodologies, the more sophisticated and impactful methodologies are less likely to be used by terrorists due to the barriers in acquiring and weaponising these materials. Therefore, lower-sophistication attacks using household substances are more likely to be conducted by terrorists in the UK.
-
We currently assess that it is unlikely that a UK terrorist individual or group would undertake a chemical or biological attack plot. Although terrorists could use online instructional material to construct crude devices, there are still some capability barriers.
-
A UK attack plot using a radiological weapon is highly unlikely because there are significant challenges in acquiring suitable radioactive sources, which are subject to controls.
-
We assess there is a remote chance of a terrorist attack plot using a nuclear weapon due to the serious obstacles in acquiring either the weapons or the fissile material and specialist knowledge needed to construct them.
What is CBRN Terrorism?
CBRN Terrorism is the term used to describe the terrorist use (or threatened use) of Chemical, Biological, Radiological or Nuclear material as a weapon, with the intention to cause harm. It is not the deployment of these materials in state-sponsored hostile acts. Hazards posed by these materials vary, but include:
-
Chemical: Poisoning or injury caused by chemical substances, including household chemicals or harmful industrial chemicals, as well as agents used during armed conflict.
-
Biological: Exposure to harmful bacteria, viruses or toxins and the illness or disease they cause.
-
Radiological: Exposure to harmful radioactive materials.
-
Nuclear: Exposure to thermal or blast effects arising from a nuclear detonation (including secondary effects from radioactive fallout).
How has CBRN previously been used by terrorist groups worldwide?
Globally, there has been a very small number of terrorist attacks where CBRN materials have been used. A chemical weapon was used against Sri Lankan Armed Forces in 1990. In Japan, a chemical weapon and a biological attack occurred against various targets between 1990 and 1995. More recently, chemical weapons have been deployed on more than one occasion on the battlefield in Syria. To date, there have been no acts of radiological or nuclear terrorism.
The threat from CBRN Terrorism in the UK
Police and other emergency services in the UK frequently deal with incidents involving CBRN-related materials, mostly chemical. While some of these will relate to the accidental release of hazardous substances, others will involve the use of such materials for criminal purposes, for example acid attacks, production of illegal drugs and sometimes the making of explosives. Although the vast majority of these incidents are not related to terrorism, they demand an equally robust response because of the health risks posed to the public.
We assess a UK chemical or biological attack plot by a terrorist to be unlikely. To date, there has been no UK terrorist attack using a chemical or biological weapon. Although terrorists could draw upon available dual-use equipment and materials as well as recipes and instructional material available on the internet to construct crude devices, there are still some capability barriers. Additionally, like all CBRN-related materials, there are inherent risks to those handling them such as accidental exposure, infection or poisoning.
We assess that an attack plot in the UK using a radiological weapon is highly unlikely. Although radiological weapons are technologically less sophisticated than nuclear weapons, there are still significant challenges in acquiring suitable radiological sources. Not only are such sources in the UK subject to strict controls, their use in specialist equipment is being phased out and replaced with less hazardous alternatives.
We assess there is only a remote chance of an attack by a terrorist group using a nuclear weapon. There are serious obstacles in acquiring a complete nuclear weapon or the fissile material needed to construct one. Activities involving nuclear material are strictly regulated in the UK and nuclear security is robust, having to meet international standards. These factors place the likelihood of a terrorist attack using a nuclear weapon at the very lowest end of the probability scale.
There are significant differences between the various Chemical, Biological, Radiological and Nuclear weapons with respect to their complexity, construction, method of delivery and effects. Consequently, the availability of materials and components required to build them will also vary, as well as the ability of terrorist groups to use them. Of the multiple CBRN methodologies, the more sophisticated and impactful methodologies are less likely to be used by terrorists due to the barriers in acquiring and weaponising these materials. Less sophisticated methods are more likely to be utilised in a terrorist attack due to the lower capability requirements.
Probability and Likelihood in Intelligence Assessments
When describing threats in intelligence assessments, Counter Terrorism Policing utilises the Probabilistic Yardstick.
The Probabilistic Yardstick is a tool created by the Professional Head of Intelligence Analysis (PHIA), in the UK government, to standardise the way in which we describe probability in intelligence assessments. For example, if we use the term ‘likely’ what we mean is ‘a 55-75% chance’.
Use the scale below as a reference when reading ProtectUK Insights.
