Significant attainment gaps are opening up in the UK between bright pupils from poor backgrounds and their richer counterparts.
This is according to new research from the Sutton Trust, which has analysed 2015 test scores from the Organisation for Economic Co-operation and Development's PISA tests to assess how well the UK's top ten per cent of pupils are performing when their economic backgrounds are taken into consideration.
It was shown that England's highest achievers generally scored above the median level for OECD countries in maths, science and reading, but the brightest pupils in Scotland, Wales and Northern Ireland performed worse on average.
Wales was shown to have underperformed to a significant degree, with only the highest achievers in Chile, Turkey and Mexico getting lower scores in reading and maths.
The report also indicated that attainment gaps of several years are emerging between poor pupils and their better-off classmates. For the brightest girls in England taking, this is equivalent to three years of schooling when it comes to science, which is eight months greater than for boys. A similar three-year gap is also evident in terms of reading skills, nine months greater than that for boys.
Although no significant gender difference was seen in maths, the gap stands at around two years and nine months for both sexes, which is a potentially significant cause for concern.
Study author Dr John Jerrim, from the University College London Institute of Education, said: "While England's brightest pupils score around average in international tests - and better in science - this analysis shows that there are some very big socioeconomic gaps in attainment between the brightest pupils from poor and better-off homes.
"There are also some very big challenges in Scotland and Wales highlighted by the research."