The Institute for Fiscal Studies (IFS) produces analysis of long range trends in school spending. This average class funding figure is based on the underlying data from the IFS’s 2017 report, converted into 2018-19 prices using the GDP deflator, which gives a per-pupil funding figure for primary schools of £4,891.41 in 2018-19. The full report is available here: https://www.ifs.org.uk/publications/8937.
This has been multiplied by 27 to generate the average class figure. The average class size for a primary school is 27.1, according to the January 2018 school census available here: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/719226/Schools_Pupils_and_their_Characteristics_2018_Main_Text.pdf.
Changes in predicted trends in inflation and the IFS’ methodology mean that this analysis may produce slightly different figures over time. The funding that individual schools receive through their local funding formulae and the pupil premium will vary depending on the characteristics of the pupils in each class.