ISO (International Organization for Standardization) is the world's largest developer and publisher of International Standards.

website : www.iso.ch  

United Kingdom Accreditation Service (UKAS information site)

website : www.ukas.com

BSI British Standards is the National Standards Body of the UK, with a globally recognized reputation for independence, integrity and innovation in the production of standards that promote best practice.

website : www.bsi-global.com 

United Kingdom Accreditation Service(UKAS calibration and testing laboratory site)

website : www.ukas.org

The National Physical Laboratory (NPL) is the UK’s National Measurement Institute and is a world-leading centre of excellence in developing and applying the most accurate measurement standards, science and technology.

website : http://www.npl.co.uk