England is neglecting its brightest children, leaving them lagging far behind youngsters overseas, new research suggests.
It reveals that the nation's teenagers are four times less likely to score the top level in international maths tests than pupils in countries such as Switzerland and Korea, and half as likely to achieve this standard than those in places like Slovenia and the Slovak Republic.
Those pupils in England who are considered to be "high performing" are most likely to attend private or grammar schools, the report says, rather than being state educated.
The Sutton Trust, which commissioned the research, said the findings paint a "deeply troubling picture" and warned that more must be done to help able students.
Researchers at the Centre for Education and Employment Research at Buckingham University examined the proportions of pupils achieving the highest levels in Organisation for Economic Co-operation and Development (OECD) tests. The PISA tests (Programme for International Student Assessment) compare the performance of pupils in different countries in subjects such as reading and maths.
The new report found that just 1.7% of England's 15-year-olds reached the highest level, Level 6, in maths, compared to an OECD average of 3.1%. In Switzerland and Korea, 7.8% of pupils reached this level.
Overall, England ranked 26th out of 34 OECD countries in terms of the proportion of pupils reaching the top level in maths, behind other nations like Slovenia (3.9%), the Slovak Republic (3.6%) France (3.3%) and the Czech Republic (3.2%), which were among those scoring around the OECD average.
The report adds that globally, the situation looks worse for England. Singapore, which is not part of the OECD table analysed, saw 15.6% of its students score the top level, while in Hong Kong and Shanghai, which were also not part of the OECD table, 10.8% and 26.6% respectively got the top level.
"This is a deeply troubling picture for any us who care about our brightest pupils from non-privileged backgrounds," Sutton Trust chairman Sir Peter Lampl says in a foreword to the report.
The study also suggests that comparing the maths results of 18-year-olds would be even more stark because 90% of English pupils drop the subject after GCSE. In many other countries, maths is compulsory up to the age of 18.