British children's chances of academic achievement are more reliant on their parents' social standing than almost any other developed country in the world, a social mobility study has claimed.
The study, published on Monday by the Sutton Trust charity, found children in Britain with "highly-educated" parents - those with degree-level qualifications - vastly outperformed those whose parents had left school without qualifications, classed as "low-educated".
The figures suggest children from poorer backgrounds are more than a year behind their better-off peers when they start school at the age of five. The gap is "significantly larger" in Britain than in all countries surveyed, other than America. In comparison, Canada was found to have the smallest difference.
The studies gauged the prospect of today's generation of children to provide an indication of mobility trends in later life. The report states education mobility levels play a particular important role in signalling the future levels of social mobility current children and young adults are likely to experience when they are older, "given the strong and persistent link between earlier educational achievement and future life prospects and earnings".
The trust conducted sixteen studies which looked what extent child outcomes relevant to mobility, such as educational attainment, vary according to family background. Comparing trends across 10 countries including the UK, Germany, Australia and the US, the data covers hundreds of thousands of children and young adults.
Data showing children's average vocabulary scores at the age of five, ranking them from one to 100.
The graph shows British children of highly-educated parents ranked in 67 on average, while those with parents who had little or no qualifications ranked on average 29.
Sir Peter Lampl, chairman of the Sutton Trust, said the problem was "likely to get worse".
"In this country, unlike others, the educational achievement gap widens after age 11. As education is becoming increasingly important in determining prospects in adult life, these findings do not bode well for future social mobility in the UK."