What We Do

Architectural statue outside Thames House

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.