About us
Find out more about MI5’s mission and core values; our people who work to keep the country safe; and our rich and varied history.
What we do
Find out about the core threats to national security that MI5 exists to protect against.
National Protective Security Authority The National Protective Security Authority (NPSA) is part of MI5 and offers advice to businesses and organisations to help keep them and their customers safe from a range of national security threats.
National Protective Security Authority
The National Protective Security Authority (NPSA) is part of MI5 and offers advice to businesses and organisations to help keep them and their customers safe from a range of national security threats.
How we work
Discover how MI5 works to protect against threats to national security through intelligence gathering techniques, partnerships and legislation.
Threats and Advice
Find out how you can play your part in keeping the country safe – either as a member of the public, or as a potential new recruit.
History
Find out more about the history of MI5.