The Register of Geographic Codes (RGC) is a 'light' but key document that contains information to manage the allocation of new codes in co-operation with the entity (‘geography’) owners. It includes details of each entity code, name and owner; the range of instance (distinct area within that geography) codes; and number of live and archived instances. The document should be used in conjunction with the Code History Database (CHD).
The RGC is available in MS Excel format contained in a zip file with accompanying metadata in XML format and product specification document. CSV files can be read in MS Excel format and all common database applications; XML files can be displayed in any internet browser.
You can download the files free of charge from the Open Geography portal.