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.
Find out about the core threats to national security that MI5 exists to protect against.
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.
Discover how MI5 works to protect against threats to national security through intelligence gathering techniques, partnerships and legislation.
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.
Find out more about the history of MI5.
