THE world’s richest nations are a long way from conquering educational inequality at home, according to a report released by the United Nations’

children’s fund’s this week.

In fact, the differences in achievement within nations are much greater than differences between nations, said the report from the Innocentie Research Centre in Florence, Italy.

International education league tables tend to obscure disparities within individual countries. Some nations that might otherwise score well are pulled down by a huge tail of underachievement.

The UN agency’s league table of educational disadvantage in rich nations looks at the gap between best and worst within a country’s education system.

The study involving 22 countries draws on existing data in the Organisation for Economic Co-operation and Development’s Programme for International Student Assessment (Pisa) study of literacy, numeracy and science skills, and the International Maths and Science Study (Timss).

Low achievers in Finland, Spain, Portugal and Canada do not fall too far behind average international benchmarks. By contrast countries such as Belgium, New Zealand, Germany and the United States are allowing very wide gaps to open up, even compared with average pupils in their own countries.

Simply put, a child at school in Finland, Canada or Korea has a higher chance of being educated to a reasonable standard and a lower chance of falling a long way behind the average than a child born in Hungary, Denmark, Greece, the US or Germany.

The UK ranks seventh overall in international comparisons. Yet, even this relatively positive showing - only two other EU countries, Finland and Austria, perform better - masks some sobering statistics.

The proportion of British 15-year-olds judged “unable to solve basic reading tasks” is 13 per cent (just 7 per cent in Korea and Finland), while the percentage considered “unable to apply basic mathematical knowledge” is a staggering 42 per cent, compared with under 10 per cent in Korea and Japan.

While the UK stacks up reasonably well internationally, there are still huge huge disparities in children’s performance.

Relative disadvantage - how many fail compared with the country’s own average pupils - shows that few countries have anything to celebrate. Even in top-scoring Finland, maths scores of low-achieving 8th grade pupils are 3.5 years behind their average classmates.

Little is known about why some countries do better in containing educational disadvantage. High-spending Scandinavian countries occupy both the higher ends of the league (Sweden) and the lower ends (Denmark). Top-ranking Korea spends approximately the same amount per pupil as the two countries at the bottom of the league, Greece and Portugal. Even income disparity is a poor predictor. Income distribution in poorly performing Germany is more equal than other large European nations. Anna Wright, the report co-ordinator, said: “Every country has its problems. There is a lot of poor educational achievement everywhere.”

In all countries, however, a strong predictor of a child’s success at school is the economic and occupational status of their parents.

“Education must be seen in combination with other social policy if the aim is to try to tackle social inequality,” said Ms Wright.