There is a wealth of data recorded and stored by government departments and from other non-government sources. These include routinely and contemporaneously collected data about health, education, environment, employment and lifestyle and which are collected by trained personnel administering and managing organisations. These data can also have an important secondary use in research, however appropriate permission and authorisation is required to allow studies in the UK to link to them. This data note describes how the Avon Longitudinal Study of Parents and Children (ALSPAC, also known as ‘Children of the 90s’) has obtained the necessary permissions to undertake this type of linkage-based resource enrichment. To make the best and most ethically sensitive use of data linkage, ALSPAC has used a blended model of consenting including direct responses from participants alongside an independently approved approach to indirect permission where it has not been practical or possible to directly contact participants. All linked datasets are available for research and may be used in conjunction with other data collected over the course of the study, including self-reported, face to face, biosamples and multi-omics.