Oxford University researchers who were involved in the Effective Pre-School, Primary and Secondary (EPPSE) project found that children who had had an early education at nursery or preschool were more likely to get better GCSE results - the equivalent of getting seven Bs compared to seven Cs.

The research found an early education particularly helped boost grades in GCSE English and maths. The effects were even more marked if the preschool was of high quality and the value of a preschool education was particularly important for children from less advantaged backgrounds, say the researchers.

The EPPSE project launched in 1997 and has followed 3,000 children from early childhood to the age of 16. The research was carried out by leading academics from Oxford, the Institute of Education, and Birbeck, University of London.

Kathy Sylva, Professor of Educational Psychology at Oxford University, one of the lead researchers, said: 'The EPPSE study is unique because it provides valuable evidence in Europe on the long term value of preschool, something no other research has done. The results are clear: early education pays off, and high quality preschool education gives children the very best start in life. High quality early education has enduring benefits for the children who experience it and also the society that invests in it.'

Research was conducted through a nationally representative sample of children in 141 preschool settings drawn in 1997 from five English regions (six local authorities). A sample of children who had no or minimal preschool experience was recruited to the study at entry to school and compared with the preschool group.

EPPSE researchers assessed the children at recruitment to the study to create a profile of each child’s intellectual and social/behavioural development using standardised assessments and reports from the preschool worker who knew the child best. Children were assessed again at entry to school and then the children were followed up at ages 6, 7, 10 and 11 in primary school and at ages 14 and 16 at secondary school. The children involved are now aged between 18 and 21. The original sample was spread over four academic years, with the youngest completing their GCSEs in 2012.

The researchers found that at GCSE, the benefits of going to preschool translated into an average of 41 extra points per child – the difference between getting, for example, seven grade Bs versus seven Cs.

Another lead researcher Professor Pamela Sammons, also from the University of Oxford’s Department of Education, said: 'This major longitudinal study is the first to investigate the influence of successive phases of education - preschool, primary and now secondary - on children's progress and development. We believe this provides new, important evidence to support the expansion of preschool provision and it should inform policy makers on how to improve the education and life prospects of children in the UK, particularly benefiting those from the least advantaged backgrounds.'