For the first time, the UK does not make the top 20 in any subject, in international tests taken by 15 year olds in maths, reading and science.
Within the UK, Scotland outperformed England at maths and reading, but Wales is below average in all subject, in the Pisa tests run by the OECD.
The Pisa tests – the Programme for International Student Assessment – have become the most influential rankings in international education, based on tests taken by 500,000 secondary school pupils.
Read the full BBC story.