The positive effect of a high-quality nursery on children's English and maths results, and their ability to interact with others, is still noticeable six years later, an influential study has found.
But poor-quality childcare is little better - and can even be worse - than simply staying at home until the age of five. The Effective Pre-school and Primary Education (EPPE) project carried out by researchers at Oxford, London and Nottingham universities has tracked the progress of 2,800 children between the ages of three and 11 since 1997.
It is one of the most important pieces of education and social policy research carried out under the Labour Government.
The project is one of the central pillars of its 10-year childcare strategy, which has led to free part-time early education places for three- and four-year-olds, the Early Years Foundation Stage and Sure Start children's centres. The Department for Children, Schools and Families spent Pounds 1.8 billion on early years programmes last year.
Now that the EPPE team's final primary report has been published, it is confirmed funding will continue to follow the pupils until 14.
The research has found that high-quality pre-schools can help close attainment gaps. They are especially beneficial for boys, pupils with special educational needs and from disadvantaged backgrounds.
The latest conclusions also underline previous work on the importance of quality.
Children who had attended a less effective pre-school are better at sharing and being sympathetic than those who had not attended at all, but were also easily distracted and had poorer concentration spans.
Going to an academically effective primary school had an effect on academic scores, but not on behaviour overall.
The home learning environment in children's early years - whether they are taken to the library, are read stories and have a regular bedtime - was a less powerful factor once children reached 11 than it was at the age of seven, but remained one of the biggest influences on children's scores.
In fact, previous EPPE conclusions had found that this home learning environment was more of an impact on children's development than their socio-economic status. A crucial recommendation, therefore, was for increased outreach work with parents - one of the key roles of Sure Start centres.
The link between quality of preschool and the qualifications of people working in them was made explicit, leading to the programme to upskill early years workers.
It also said youngsters who had spent long hours in group settings before they were two showed more anti-social behaviour at three and five.