Appendix A: UK LLC Data Flows

Appendix A: UK LLC Data Flows#

Last modified: 20 May 2026

A 'split-file' anonymisation process is used to securely transfer all datasets from contributing LPS into the TRE.

Importantly, this ‘split-file’ anonymisation process restricts the handling and management of LPS participants’ personal identifiers to:

  • the contributing LPS,

  • NHS Digital Health and Care Wales (UK LLC’s trusted third party/linkage broker),

  • the linked data owners, and

  • the contracted geo-data modellers.

Staff at Swansea University and University of Bristol, and researchers approved to access data in the TRE, only have access to the de-identified data.

For UK LLC data flow diagrams visit: Partnering with UK LLC - Resource Hub

For more information on NHS England data linkage visit: Processing and linkage to NHS England datasets

For more information on NHS Wales data linkage visit: Processing and linkage to NHS Wales datasets

For more information on Place-based data linkage visit: Processing linkage to place-based datasets

File 1s are processed by NHS DHCW who:

  1. Reformat and send the identifiers to linkage partners and data sources to establish linkages.

  2. Provide an automated file of de-identified participant permission status and linkage field quality indicators (reporting if an identifier was present in the file or not) to Swansea.

  3. De-duplicate each LPS participant’s identifiers into a single file of unique individuals.

  4. Encrypt the study identifiers used into a unique UK LLC person ID and encrypt property details into a UK LLC property ID (TBC). These IDs are shared with Swansea University who encrypt them again before providing the IDs to UK LLC.