UK boundary data shapefiles where features have attributes pointing to their parent subdivision?

Question

I know similar questions have been asked before but none have given me exactly what I need. I am trying to find boundary shapefile data for the UK which splits different subdivisons into different layers (the exact number of subdivisions doesn't matter), with each feature of a layer referencing it's parent in the above layer.

I would like the data to be 'clean' in that each layer only has appropriate regions, e.g. a county and city aren't on the same layer, so that all features of a layer are of a similar size and no features are surrounded entirely by another feature on the same layer (an enclave).

The closest I have got so far is at gadm.org, which provided shapefiles with perfect attributes, however Unitary Authorities were listed separately to their parent county on the same layer (e.g. Nottingham was an enclave within Nottinghamshire on the county layer, and thus in the next layer down Nottingham's parent layer was Nottingham, not Nottinghamshire). I could merge these and change the data for the parent, but this would have to be done manually which isn't preferable.

Answer 1

The issue here might come from the official definitions of the hierarchy of local authorities in the UK being somewhat counterintuitive.

As I understand it (correct me if I'm wrong) you want a spatial layer showing the outlines of all lower-tier local authorities (e.g. districts, boroughs etc.) and including a column showing which county each local authority is in. The problem comes about because unitary authorities are not formally 'in' counties for local government or statistical purposes.

This means (to extend your example) the City of Nottingham unitary authority is not in the County of Nottinghamshire as far as the government is concerned: Nottinghamshire is a doughnut with Nottingham being the hole in the middle. This is particularly counterintuitive because Nottingham is served by Nottinghamshire Police, Nottinghamshire Fire and Rescue etc, but nevertheless Nottinghamshire County Council has nothing to do with services in the City of Nottingham.

As you've noted, you can manually construct a layer using existing open data – either from GDAM or the UK Data Service boundary data site. Alternatively, you might want to look at the Ordnance Survey Boundary Line product, which is open data and includes layers for English ceremonial counties. This layer might give you the result you want (or allow you to create it using a spatial join) because, for example, Nottingham is in the ceremonial county of Nottinghamshire.

One important thing to note, though, is that this will not help you for those parts of the country where the creation of unitary authorities means that there are no longer any lower-tier local authorities. For example, there are no longer any districts or boroughs inside the counties of Cornwall, County Durham, Northumberland, Shropshire or Wiltshire.