The National Security Inspectorate (NSI) is recognised as the leading certification body for the security and fire protection sectors in the UK. For over 40 years, it has protected businesses and homeowners by providing robust, high-quality audits of home and business security and fire safety service providers. Businesses and homeowners who choose NSI-approved companies have the reassurance that their chosen contractors will work to the highest industry standards demanded by the Police, Fire and Rescue Services and the insurance industry. The NSI Directory lists all the companies who have successfully achieved NSI certification.