Results cast doubt on Swedish success
Its school reforms have been lauded by all three British political parties as a possible pointer for the future here.
Beyond education, it is also often held up as a model of social democratic reform and as something of a nirvana for left-leaning progressives everywhere. It is now even providing the prosperous backdrop for a prime-time BBC TV detective series, while a homage to its most famous musical export outsells all others in the Christmas DVD charts.
But the latest Timss results might bring Sweden down to earth as it languishes beneath England in all four Timss tests, its secondaries having plummeted down the rankings since 1995.
In results that might trigger a bout of soul-searching from the Conservative party in particular - it was praising its reforms only two months ago - Sweden finished 15th in primary maths, 14th in primary science, 18th in secondary maths and 16th in secondary science.
Sweden took part in the Timss primary tests for the first time last year. At secondary, its results have fallen by 48 points in maths and 42 in science since 1995.
The Conservatives have looked to model aspects of their reforms on Swedish "free schools" policy, whereby parents would be allowed to take money used by a local authority to fund their child's education to set up a new school.
The Liberal Democrats have also backed the policy, which was introduced in Sweden in 1992, while the Government also praised it in a 2005 white paper.
Professor Alan Smithers, of Buckingham University, said: "This does underline the fact that we should be cautious in setting up other countries as paragons of virtue, when they can always be found out by international testing studies."
Closer to home, England also beat Scotland in all four tests. Scotland finished just below the international average in secondary maths and science, and in primary maths. In secondary maths, its score was in line with the average.
The latest results contrast with the Organisation for Economic Co-operation and Development's Pisa study last year, in which Scottish pupils finished ahead of their English counterparts in reading and maths, but the English pupils did better in science.
Further reports, pages 20-21.