UK Administrative Geography Lookup for Wards to Countries, December 2016
Office for National Statistics provides a lookup table linking UK wards to local authority districts, counties, regions, and countries as of 31 December 2016. The dataset contains 9,130 wards after a correction for duplicate codes in version 2. It is available in CSV, GeoJSON, and ESRI REST formats under an OGL-UK-3.0 license.