From 1 May 2018 the NPD have temporarily paused all applications for data extracts, and will not be processing new applications as they review the approvals process. More information on the changes to the approvals processes will be communicated after 1 June 2018. If you have an outstanding application you can email: NPD.requests@education.gov.uk.
National Pupil Database is the national repository for detailed information about pupils in schools and colleges in England. The data includes both academic achievement records, as well as characteristics of the pupils, such as their background, and absence and exclusions. The data is made available for research, producing statistics and providing information or guidance for promoting the education or well-being of children in England. The NPD also processes applications for linked data sets and for datasets from individualised learner records (ILR), and the Higher Educations Statistics Agency (HESA).
More information can be found here: https://www.gov.uk/guidance/national-pupil-database-apply-for-a-data-extract