UK council structure

Council set up in the UK is complex historically, and MapIt UK includes that in its data for those people who need it in some way. Some areas of England have two tiers of council – a county council (CTY) covering the area of several non-metropolitan district councils (DIS). Other areas only have one tier of council, either a metropolitan borough (MTD) covering the areas of the now extinct metropolitan counties; a London borough (LBO) covering the Greater London Authority (technically not including the City of London but we class that as one); the Isles of Scilly (COI); or a unitary authority (UTA).

Scotland and Wales councils are all unitary authorities (UTA); Northern Ireland has local government districts (LGD).

A MapIt UK postcode lookup includes a "shortcut" parameter that links to the council and ward IDs for that location. e.g. GL50 2PR returns "shortcuts": {"ward": {"county": 143641, "district": 4544}, "council": {"county": 2226, "district": 2326}} and N1 0LA returns "shortcuts": {"ward": 8625, "council": 2507}. The IDs can be looked up in the main returned data.

https://en.wikipedia.org/wiki/Local_government_in_England#Principal_authorities has more details.