It is a fair bet that when this summer’s exam results come out in August there will be another round of hand-wringing about what can be done to boost boys’ achievement. After decades of girls’ underachievement the tables have truly been turned. The extent of girls’ dominance is such that they now do better than boys in GCSE maths, traditionally a male stronghold.

But any feminists tempted to feel smug should study a report published last week by the Paris-based Organisation for Economic Co-operation and Development. Flying in the face of conventional wisdom and national curriculum test scores, Education at a Glance 2001, the OECD’s annual digest of educational statistics, suggests that in England, girls are further behind boys in maths and science than in any of the 13 other developed countries for which data are available.

It says that the difference in maths scores is greater than in any of the other countries. Only the Czech Republic has a bigger gender gap in science. New Zealand and Belgium are the only countries where girls’ maths skills are better than boys’.

The findings are based on TIMSS-R, the follow-up to the Third International Mathematics and Science Study that was originally conducted in 1994-5. The TIMSS-R tests of 13-year-olds were carried out in 1999, the year that the national numeracy strategy was introduced in primary schools.

Steve Abbott, president of the Mathematics Association, said he was surprised by the results. “There is nothing in the Government’s key stage 3 strategy that is particularly irected towards girls. It may be that they weren’t aware of this problem before now,” he said.

But Tony Gardiner, reader in maths and maths education at Birmingham University, believes that changes in domestic tests have blinded us to a gender gap that has never gone away.

“We have in the past 15 years nominally improved the performance of girls, not by improving their performance but by changing the way we assess them, for example increasing the amount of coursework.

“TIMSS-R are not exams we have set ourselves which allow us to cheat. This is how we do by an international yardstick. We believe our statistics show girls getting better, but they don’t. Girls themselves realise this, which is why so few choose maths at A-level,” he said.

Celia Hoyles, professor of mathematics education at the Institute of Education, says that different types of questions in the TIMSS-R tests could go some way to explaining the gender gap. But she also points out that while teachers tailor lessons to domestic tests the TIMSS-R questions could be unfamiliar to pupils.

This could help explain another worrying aspect of the report. Overall, England came close to the bottom of the maths league table. Italy and New Zealand were the only countries where pupils did worse. To make matters worse, England was one of only five countries whose results fell between 1995-9.

A spokesperson for the Department for Education and Skills said that the national numeracy strategy would help English pupils catch up. “It is too early for the impact to be reflected in these test results, but in time we expect to see the benefits in any future surveys of this kind,” she said.