Terrorism threat levels

The national threat level from all forms of terrorism is: SUBSTANTIAL – An attack is likely.  

You can find more information on the MI5 website. 

Threat levels

There are five categories of threat levels:  

• LOW - an attack is highly unlikely
• MODERATE - an attack is possible, but not likely  
• SUBSTANTIAL - an attack is likely  
• SEVERE - an attack is highly likely  
• CRITICAL - an attack is highly likely in the near future  

Reporting suspicious activity 

Members of the public should always remain alert to the danger of terrorism and report any suspicious activity to the police by calling 999.

You can also call the anti-terrorist hotline: 0800 789 321.  

If your information does not relate to an imminent threat, you can contact MI5. 

Northern Ireland threat level

JTAC also sets the threat level from Northern Ireland Related Terrorism in Northern Ireland.  

The threat to Northern Ireland from Northern Ireland-related terrorism is SUBSTANTIAL.

Threats to national security 

Understanding the threats facing us is key to ensuring protective security measures are in place and that any mitigations are proportionate, effective and responsive.

The main threats to national security, which can impact on the UK’s national infrastructure, include:  

• Terrorism
• Espionage
• Cyber threats
• The proliferation of weapons of mass destruction

How threat levels are decided

The Joint Terrorism Analysis Centre (JTAC) is responsible for setting the national threat level for the UK from terrorism.

The national threat level covers all forms of terrorism aside from Northern Ireland-related terrorism within Northern Ireland.  

Threat levels consider the threat from all forms of terrorism, including:  

• Islamist terrorism
• Extreme right-wing terrorism
• Left Wing, Anarchist and Single-Issue Terrorism (LASIT)  
• Northern Ireland terrorism

Threat levels do not have any set expiry date but are regularly subject to review to ensure that they remain current. 

To reach a judgement on the appropriate threat level in any given circumstance, some factors are taken into consideration. 

These include:

• Available intelligence  
• Terrorist capabilities
• Terrorist intentions
• Timescale 

Further information  

You can find out more about terrorism threat levels and how they are decided on the MI5 website, as well as information, updates and how to receive threat level change alerts.