A three digit number unique to each council with adult social services responsibilities. NOTE: same as the CASSR code

CASSR/Local Authority codes are maintained by NHS Digital's Organisation Data Service (ODS). Most codes are three-digit numeric, but codes issued since 2021 have been five-character alphanumeric (ANANA). They are used exclusively in the NHS, and differ from the nine-character local authority codes maintained by the Government Statistical Service (GSS), which are part of a definitive national code list used throughout government (https://geoportal.statistics.gov.uk/datasets/ons::lower-tier-local-authority-to-upper-tier-local-authority-december-2022-lookup-in-england-and-wales/explore).

The Office of National Statistics (ONS) advised in 2011, when the GSS coding and naming policy for some statistical geographies was implemented on January 1st, that the new codes should be used in all exchanges of statistics and published outputs that normally include codes. (See https://www.get-information-schools.service.gov.uk/Guidance/LaNameCodes.) However, the NHS and the Department for Education both continue to use their own (different) three-digit codes for most internal purposes.