The National Security Inspectorate, or NSI, is an independent not for profit UKAS accredited certification body operating in the United Kingdom.
It serves to approve around 1800 professional security and fire safety providers in accordance with International, British and Industry Standards and Codes of Practise, who are listed in the NSI Company Finder.
It works closely with public authorities, trade associations, insurers and other in the development of standards.
All NSI approved companies are regularly audited, required to make good identified shortcomings.
See the NSI company finder for Approved Companies The other main similar certification organisation is the Security Systems and Alarms Inspection Board (SSAIB)[1] of Tyne and Wear, which offers similar services.