An international expert described by Michael Gove as "the most important man in the world of education" has publicly contradicted a central pillar of the Westminster Government's schools policy.
German mathematician Andreas Schleicher was praised by Mr Gove this year for his leadership of the Organisation for Economic Co-operation and Development's Pisa (Programme for International Student Assessment) study (see box).
But the two men have drawn widely differing conclusions from the evidence on school performance in the world's most advanced economies.
The Coalition Government's Importance of Teaching white paper used Pisa findings to back its case that improving the quality of teachers should be at the heart of education reform. This includes a new minimum requirement of a 2:2 degree for new entrants.
"Top-performing countries consistently recruit their teachers from the top third of graduates," the white paper, published last year, notes.
But Mr Schleicher disagrees. "The frequently cited claim that the best- performing education systems all recruit their teachers from the top third of graduates . is not supported by evidence," the German writes in a report for a summit on teachers in New York last month.
Mr Schleicher also argues for more money to be spent on training existing teachers.
"Successful reform cannot wait for a new generation of teachers," his report says. "It requires investment in the present teacher workforce."
John Bangs, a member of the OECD's trade union advisory committee, said: "Given Michael Gove's commitment to international evidence and the OECD, the very first thing he should do is drop the idea that recruiting top graduates is the right strategy."
The Government's white paper pledges to "develop sustainable approaches to teacher development" and to ensure that teachers have "support" for on- the-job training.
But by giving money for training straight to schools, ministers were failing to meet their white paper promises, said Mr Bangs.
A Department for Education spokesman said: "We agree with Andreas - world- class systems have not just tough recruitment, but rigorous ongoing training throughout teachers' careers. That is why we are creating a new national network of Teaching Schools and making sure outstanding staff and schools lead professional development."
IN A LEAGUE OF ITS OWN?
- Pisa measures the success of schools in 70-plus economically advanced countries;
- It has assessed international standards in reading, maths and science in 2000, 2003, 2006 and 2009;
- The Government uses the UK's relative decline in Pisa over the past decade to support its argument for reform;
- This includes the 2000 results, which the OECD now says are statistically invalid;
- Ministers have not highlighted the Trends in International Mathematics and Science Study, in which England performs much better than in Pisa rankings.