Although Scotland's education system has always been well-respected, the Scots children fared even worse than the English in the maths tests and their science scores were significantly lower.
The Scots will point out that their children were among the youngest to be tested and that they had been in secondary schoool for a year less than the English youngsters. The test questions were also slightly less relevant to their curriculum, particularly in science.
Nevertheless, the TIMSS findings will make depressing reading for Scotland's education administrators. Previous international studies have indicated that there was no appreciable difference in the science performance of English and Scots pupils.
But this study shows that a gap has opened up between the two countries.
The average science score for Year 9 English pupils was 61 per cent whereas the Scots scored only 55 per cent. Furthermore, whereas 17 per cent of English pupils were within the top 10 per cent internationally, only 9 per cent of Scots children reached that standard.
The Scots did reasonably well in physics and science and the environment but were below the international average in earth science, life science and chemistry.
In maths, the Year 9 English pupils only just pipped the Scots (53:52 per cent) but a slightly higher proportion of the English children were within the top 10 per cent internationally (7 per cent compared with 5 per cent in Scotland).
Though the English pupils' maths performance was far from impressive, the Scots children scored even lower marks in each of the six categories tested: fractions and number sense; geometry; algebra; data representation, analysis and probability; measurement and proportionality.