British Standards institute (BSi) is a national organization for standardization of the United Kingdom. It was founded in 1901. Since then its main activities are facilitating, drafting, publishing and marketing British Standards and defining other guidelines. Most of the BS standards are developed in cooperation with other standardisation organisations at international and European level such as ISO, IEC, CEN, etc.

Furthermore, BS adopts all European standards, which are developed by European standardisation organisation and replaces or reprocesses the existing British Standards that conflict with them. Then the standards are published as adopted British Standards with abbreviation BS EN, BS ISO, etc.