ISO 3166-2:GB is the entry for the United Kingdom of Great Britain and Northern Ireland in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions (e.g., provinces or states) of all countries coded in ISO 3166-1.[1] The codes and structures used are provided to the ISO by British Standards and the Office for National Statistics.
Currently for the United Kingdom, ISO 3166-2 codes are defined for the following subdivisions:
Each code consists of two parts, separated by a hyphen. The first part is GB, the ISO 3166-1 alpha-2 code of the United Kingdom. The second part is three letters, which is the British Standard BS 6879 three-letter code of the subdivision.
Though GB is the United Kingdom's ISO 3166-1 alpha-2 code, UK is exceptionally reserved for the United Kingdom on the request of the country. Its main usage is the .uk internet ccTLD and, on 28 September 2021, UK replaced GB as the official country code on car registration plates.[2]