ISO 3166-2:GB is the entry for the United Kingdom of Great Britain and Northern Ireland (GBNI) 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 divisions and subdivisions (e.g., provinces or states) of all countries coded in ISO 3166-1. The codes and structures for the United Kingdom (UK) are provided to the ISO in Geneva by the British Standards (BS) and the Office for National Statistics (ONS).
Primary divisions
Currently for the United Kingdom of Great Britain and Northern Ireland, ISO 3166-2 codes are defined for the following primary divisions and subdivisions:
- Three countries and one province, as follows:
;England
- 25 two-tier counties, 36 metropolitan districts, 58 unitary authorities, 32 London boroughs, and one city corporation
the standard has codes for the divisions in place until 31 March 2023. On 1 April 2023, the non-metropolitan county of Cumbria was abolished and replaced by two unitary authorities (Cumberland and Westmorland and Furness), as well as the non-metropolitan counties of North Yorkshire and Somerset became unitary authorities, which are not reflected in ISO 3166-2.
;Northern Ireland
- 11 districts
;Scotland
- 32 council areas
;Wales
- 22 unitary authorities
Each ISO 3166-2:GB code consists of two parts; both parts are in upper-case capital letters, and are separated by a hyphen (without spaces). The first part for the is , the ISO 3166-1 alpha-2 code of the United Kingdom of Great Britain and Northern Ireland. The second part is three letters, which is the British Standard three-letter code of the individual subdivision.
Though is the United Kingdom's ISO 3166-1 alpha-2 code, is exceptionally reserved for the United Kingdom on the request of the country (United Kingdom). Its main usage is the internet country code top-level domain (ccTLD) and, on 28 September 2021, replaced as the official country code on motor vehicle registration plates.
Current codes
Subdivision names are listed as in the ISO 3166-2 standard, as published by the ISO 3166 Maintenance Agency (ISO 3166/MA).
gives alternative name forms in Welsh () for some of the Welsh unitary authorities (together with alternative code elements). Since this part of ISO 3166 does not allow for duplicate coding of identical subdivisions, such alternative names in Welsh and code elements are shown for information purposes only in square brackets after the English name of the subdivision.
Included for completeness
{|class="wikitable sortable"
!code!!name
|-
|||England and Wales
|-
|||Great Britain
|-
|||United Kingdom
|}
The codes , , and are only mentioned in remark part 2 in the ISO website, where they are 'included for completeness'.