Owen Boswarva's blog

This is the latest in a series of blog posts about the campaign for open address data in the UK. Previous posts are listed at the bottom.

In this post, I describe a new open address dataset released by Mid Sussex District Council.

Background

As related in previous posts, I have recently been requesting Council Tax address datasets from a number of local authorities in England, and asking for permission to re-use the data under the terms of the Open Government Licence.

I have created a landing page on my Datadaptive site with download links and other information about the Council Tax address datasets released as open data so far:

www.datadaptive.com/addr/

Release from Mid Sussex District Council

The latest council to release its Council Tax address list is Mid Sussex District Council in the South East region of England.

This is another somewhat convoluted case. In its initial response, the Council disclosed most of the requested information but more than 30% of the Unique Property Reference Numbers (UPRNs) were missing. The UPRNs are an important part of my requests because they can be used to match the Council Tax list to a range of existing publicly available information, including geographic coordinates for each property.

I asked the Council to carry out an internal review of its handling of my FOI request. In its internal review response, a couple of months later, the Council said that it was withholding the missing UPRNs on the basis that the work required to append them to the records in the Council Tax list would exceed the cost limit in the FOI Act.

I accepted that decision. However, the Council also provided a response to my re-use request with regard to the disclosed information. The Council granted permission for re-use of the Council Tax bands, local property references, and UPRNs – but said that it could not permit re-use of the addresses and postcodes in the list.

I understood from the response that the Council considered that Ordnance Survey and Royal Mail had intellectual property rights in the addresses and postcodes, which the Council was not authorised to license for re-use.

I asked for an internal review of the Council's handling of my re-use request also. This week the Council provided the outcome of that second review.

I am happy to say that the Council has revised its position and granted permission for re-use of all of the information in the disclosed Council Tax list under the terms of the Open Government Licence – with the exception of the supplied postcodes.

You can download my correspondence with the Council: CT_address_list_Mid_Sussex_R335586_[NO_DATA_correspondence_only].zip (1.0 MB).

Thanks to Council staff for facilitating the disclosure and open licensing of this data.

Access to this dataset

I am not publishing Mid Sussex District Council's address dataset here, due to the non-specific but lingering risk of further unsubstantiated claims of infringement from Ordnance Survey and GeoPlace LLP. You can read more about that issue in my blog post from May.

However, there is nothing to stop you asking the Council directly for a copy of the data file. For tips on submitting access to information and re-use requests see this other blog post. My requests to Mid Sussex District Council were submitted on 2 March 2026 and the Council's reference is R335586.

More about Mid Sussex District Council's address dataset

Mid Sussex District Council has disclosed its Council Tax address dataset to me in the form of an Excel workbook '136441_midsussex_prop_data.xlsx' that contains 71,413 records. Each record includes the full address (in four fields), postcode, Council Tax band, local property reference, and Unique Property Reference Number (UPRN), for a domestic property in the Mid Sussex District Council area.

Most of the information in the list seems to be well-maintained but no UPRN values have been given for about 34% of the records. Where UPRNs values have been given, a significant number are partial or placeholder strings rather than valid UPRNs. Some of the valid UPRNs contain leading zeroes that should be removed prior to matching with other datasets.

After fixing obvious errors in a small number of UPRNs, I was able to match 43,451 (60.84%) of the 71,413 records to records in the June 2026 release of Ordnance Survey's OS Open UPRN product. 466 of the records that matched to that release of OS Open UPRN did not match to records in the March 2026 edition of ONS's National Statistics UPRN Lookup (NSUL).

This means a majority of the property records in the dataset can be geocoded for mapping and geographic analysis of domestic properties in the Mid Sussex District Council area, and also that postcodes (from an alternative open source) can be added to most of the addresses. However, the lack of completeness in the UPRNs may create difficulties for some purposes.

Please see the ReadMe file with the correspondence for a required attribution statement and additional technical details about the dataset.

Screenshot of geocoded Mid Sussex District Council address data visualised in Leaflet with background mapping from OpenStreetMap