The attainment gap between advantaged and disadvantaged pupils widens dramatically between the ages of seven and 14, government statistics reveal.
Pupils claiming free meals, used as an indication of disadvantage, perform less well on average than other pupils in all subjects at all levels. But the gap between children on free meals and their more privileged classmates doubles by the time they are choosing their GCSEs.
Professor David Jesson, of the probability and statistics department at the University of Sheffield, said: "It is a substantial gap at 14. It is a surprise because the Government's programme has sought to close the gap between disadvantaged and advantaged communities.
"The whole impact of the educational reforms has been to encourage schools in disadvantaged areas to try to match their peers elsewhere.
"As an indication of pupils' attainment, this statistic is a worrying one."
At age seven, 80 per cent of pupils on free meals achieved the expected level in maths in 2003 compared to 93 per cent of pupils who do not claim free meals.
By age 14 the gap has more than doubled. In 2003, 46 per cent of pupils on free meals achieved level 5 compared to 75 per cent of other pupils. Last year, fewer than one in four children on free meals got five or more good GCSEs, compared to more than half of other pupils.
The Government's Excellence in Cities programme, covering 1,000 secondary and primary schools, pours extra resources into urban areas. It was extended in December 2003 to cover all primaries with more than 35 per cent of pupils on free meals.
The statistics also reveal how pupils compare in terms of race, gender, English as an additional language and special educational needs.
Girls outperform boys in all measures, except the maths and science tests taken at age 11.
Chinese pupils are the highest-performing ethnic group at all ages. Indian and Irish pupils also outperform white British pupils. Ethnic groups performing less well than white British pupils are Bangladeshi, Pakistani and black pupils of all backgrounds. Pupils from traveller and gypsy families perform least well: fewer than a quarter leave primary school with the expected level in English and a fifth leave secondary school with no GCSEs or GNVQs.
The classification of different ethnic groups has changed since last year to divide white pupils into different groups and include mixed-race pupils.
A rough comparison shows that in 2003 more pupils of all ethnic backgrounds, except black pupils who were not Caribbean or African, achieved at least five good GCSEs. In primary schools, more black pupils did well in English in 2003 than in 2002.
A Department for Education and Skills spokesperson said: "Recent publication of the GCSEGNVQ performance tables showed that schools and pupils in the toughest areas are doing better than ever before.
"Excellence in Cities schools improved by 2.6 percentage points on last year's results (41.3 per cent to 43.9 per cent) compared to a 1.3 per cent increase nationally. This is a tribute to the hard work of pupils and teachers in these challeging areas."
14-year-olds' English results rankedby race
2 White and Asian *
5 White British
6 White and Black African *
7 White and Black Caribbean *
10 Black Caribbean
11 Black African
12 Traveller of Irish Heritage
* mixed race