Children from disadvantaged backgrounds are up to a year behind on educational development by the age of three, a study says.

Children of graduates were 12 months ahead in a “school readiness” assessment that tested more than 11,500 three-year-olds’ understanding of colours, letters, numbers, sizes and shapes. They also outperformed other children in vocabulary tests. The results are presented in the Institute of Education’s Millennium Cohort Study of children born between 2000 and 2002.

It also finds that children of black Caribbean, black African, Bangladeshi and Pakistani backgrounds are more likely to be delayed in their development, and more likely to live under the poverty line. A quarter of the black Caribbean and black African children who took the school readiness assessment were delayed in their development, compared with 4 per cent of white children.

Kirstine Hansen, of the Cohort Study, said: “Before drawing firm conclusions we will need to investigate the circumstances in which the assessments were done, allowing for whether children lived in homes where English was not the main language spoken.”

Those in families above the poverty line were five months ahead of those below the poverty line in the vocabulary test and ten months ahead in the school readiness assessment.

Fewer than one in four white and Indian families reported incomes below the poverty line, compared with 42 per cent of black Africans and black Caribbeans. But a third of youngsters from black African families and 47 per cent of the black Caribbean children had lone parents, compared with 14 per cent of white children and five per cent of Indians had lone parents. Fewer than one in ten Bangladeshi and Pakistani children had lone mothers but their parents were less likely to be employed and more likely to have large families.

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