To report an imminent threat call 999 or ring the Anti-Terrorist Hotline on 0800 789 321
Current Threat Level: SUBSTANTIAL
Find out more about terrorism threat levels
What We Do
Protecting the UK
MI5 protects the UK against threats to national security.
Threats can range from terrorism to attempts by states to harm people in the UK and undermine our way of life.
We carry out investigations by obtaining, analysing and assessing intelligence, and then work with our partners to disrupt these threats.
Through our protective security arm – the National Protective Security Authority – we provide advice and guidance to government, businesses and other organisations about how to keep themselves safe.