School census data cover a range of characteristics of pupils and their schools as of January each year, including first language and ethnicity of pupils. After 2018, the school census no longer includes country of birth and nationality. School census data are provided by local authorities to the Department for Education (DfE), which then processes them and subsequently make aggregate level data publically available in the form of tables. To protect confidentiality, only data which cannot identify an individual pupil in a given school are made publicly available.
For more information about these data, and to see the share of primary and secondary pupils with a first language other than English in local authorities, see Figure 12 of this guide.