City of London Police update on change to national threat level: November 18 2021

Following a change to the National Threat Level, please see below a message from Mark Haddon, Counter Terrorism Security Advisor at City of London Police; 

Following the Liverpool Women’s Hospital incident, which has been declared a terrorist incident, the Joint Terrorism Analysis Centre (JTAC) took the decision on 15 November to raise the UK National Threat Level from SUBSTANTIAL, meaning an attack is likely, to SEVERE, meaning an attack is highly likely.  

The decision was mainly driven by the frequency of attacks – there have been two terrorist attacks in the last month; the incident in Liverpool and the killing of Sir David Amess MP on 15th October 2021. Previously a quick succession of attacks can be seen to create momentum and galvanise Self-Initiated Terrorists (SITs).  

Although the threat level has risen, the expected response remains at ‘Heightened’ – This means that ‘additional and sustainable protective security measures should be in place reflecting the broad nature of the threat combined with specific business and geographical vulnerabilities and judgements on acceptable risk.’ We would therefore ask our business community to review security processes and procedures as well as arrangements around any future events to ascertain whether any additional security measures are required.  In particular we suggest that organisations refresh their knowledge and operational plans and responses with regard to ‘Improvised Explosive Devices’ (IED’s). An IED potentially enables an agile and penetrative delivery of a smaller explosive device to a target. We would like to remind security personnel and organisational staff that IED’s can come in any form, shape or size, and that they can be hidden. Communities defeat terrorism. It remains vitally important that the public are not alarmed by the change in threat level but remain vigilant and report any suspicious activity to police.  

We would draw attention to the nationally available Action Counters Terrorism (ACT) advice available on the following link. Further advice and guidance can be provided by the City of London CTSA office at