The Office for National Statistics coding system is a hierarchical code used in the United Kingdom for tabulating census and other statistical data.
Authorities, wards, and census areas
The code is constructed top down from a 4 character code representing a unitary authority or administrative county & district, eg:
| 00EC | Middlesbrough (unitary)
|
| or
|
| 12 | Cambridgeshire county
|
| 12UB | Cambridge district
|
Local Government wards have a two-letter code within their local authority, and census Output Areas an additional 4 digits within a ward. Output Areas are the smallest unit for which census data is published - they contain at least 40 households (preferably 100), and are built up from postcode blocks after the census data is available, with a view to being socially as homogeneous as possible. A new set of Output Areas will be created for each decennial census. Census 2001 was the first to use this system - previously census data was published for larger Enumeration Districts which were delineated before the census was conducted. Enumeration Districts are still used for the collection of data but not for publication.
| 12UB | Cambridge district
|
| 12UBGA | Petersfield Ward
|
| 12UBGA0001 | Output Area: Gwydir Street (north of junction with Hooper St)
|
The authority and ward codes are recognised by Eurostat as Local administrative unit code levels 1 & 2 within the NUTS system.
Civil parishes
An overlapping system encodes Civil Parish areas. Parishes are represented by an additional 3 digits within their local authority:
| 12UD | Fenland district
|
| 12UD010 | Tydd St. Giles parish
|
ONS codes for counties & districts
Also showing NUTS(3) codes thus: (UKH12)
Single-tier districts
Two-tier counties & districts
Northern Ireland districts
Non-hierarchical codes for summary data in metropolitan areas
External link
ONS Beginners' Guide to UK Geography
