The Administrative Data Research Network (ADRN) is “a UK-wide partnership between universities, government departments and agencies, national statistics authorities, the third sector, funders and researchers.” It works with researchers and government departments to provide access to administrative data on a case-by-case basis. Examples of the records they have previously provided include Child Benefit dataset, Road Accident data, Citizens Advice dataset and the General Practitioner Patient Register. In order to access data through the network, research team members are required to confirm that the data cannot be easily accessed through other routes, that there is clear scientific merit to the study, and to undergo accreditation through the ADRN.
So, if your next research study requires administrative data, it could be worth considering whether the ADRN may be able to provide it. Their website can be found at http://adrn.ac.uk/.