Since its earliest days, MI5 has worked to reduce the UK's national security vulnerabilities. The National Protective Security Authority (NPSA) is part of MI5 and offers advice to businesses and organisations of all shapes and sizes to help keep them and their customers safe from a range of national security threats. This include providing advice to the UK's critical national infrastructure - the key assets that are vital to the continued delivery and integrity of essential public services...
MI5's mission is to keep the country safe. For more than a century we have worked to protect the UK from a range of threats, whether it be from terrorism or hostile activity by states.