It is crunch time for Government as pupils' grades are measured against the rest of the world
Thousands of pupils across Britain embarked on a series of tests this week, which will enable the country's education performance to be ranked against others worldwide.
The results will be particularly interesting because they will be the first of their kind taken by children who have spent virtually all their school life under this Government, making them a key barometer of New Labour's performance.
Around 4,500 English 15-year-olds, in 190 schools, have been entered for the tests run by the Organisation for Economic Co-operation and Development in 57 countries. The Programme for International Student Assessment (Pisa) tests, in English, maths and science, are now used to rate education systems across the globe.
This year, schools had to be bribed by the Government to take part, after the UK was the only country barred from official publication in the last round of Pisa in 2003. That year, many English schools refused to take the tests, partly because of assessment overload and partly because they were held in April, as pupils were preparing to take their GCSEs.
The OECD therefore ruled the sample was not large enough for the results to be representative.
The Government has since argued successfully for the UK to be allowed to take the 2006 tests in the autumn, when the timetable is less crowded. It also offered schools pound;1,000 each to take part, and the chance to attend a post-testing conference and gain individual feedback on the results.
This year's 92 per cent take-up rate in England is comfortably above the OECD's minimum figure of 85 per cent.
John Bangs, National Union of Teachers head of education, said: "This is welcome news. The reason English schools did not sign up last time was that our schools are the most over-tested in the world.
"Moving the tests to November makes it easier for them, and the improved take-up shows there's a genuine enthusiasm for Pisa."
The results can be crucial to the way a country's schools are viewed. A bout of national soul searching broke out in Germany after its previously well-regarded schools performed poorly in Pisa 2000. By contrast, Finland has hosted international conferences on the secrets of its success since topping Pisa in 2003.
A Department for Education and Skills spokesman said: "The department has been working in consultation with head teachers and the teacher unions to come up with a package of measures designed to help raise participation rates for Pisa 2006.
"That recruitment has gone well and we are confident that we will meet the OECD targets for Pisa take up."