What is NSI approval?

The National Security Inspectorate is a UK inspectorate body that audits security and fire companies against the relevant standards and lists those that pass on a public register. NSI approval is one of the two routes — the other is SSAIB — by which an installer or Alarm Receiving Centre qualifies to obtain police response for its customers.

NSI operates tiers, of which NSI Gold is the best known. Gold adds a certificated quality management system on top of the technical standards, so it indicates the company has been audited as a business as well as on its installations.

What matters for you is narrower than the marketing suggests. Approval is what makes a company eligible to apply for URNs and to have its work accepted for police response. It also means somebody independent has inspected the work rather than taking the company's word for it.

Approval is granted to a specific legal entity for a specific scope of work. A company approved for intruder alarms is not automatically approved for CCTV or fire, and a group company's approval does not extend to a subsidiary or a subcontractor. Check the register for the exact entity that will sign your contract.

The register is on the NSI's own website and is the only claim worth relying on. A logo on a van or a website is not evidence.