As he well knows, the boycott argument is not against testing as such but against the damaging effects of high-stakes national curriculum tests on teaching and learning.
They are effects that the Scottish and Welsh governments have taken so seriously that they have commissioned fundamental reviews and have started to dismantle national testing. Yet ministers are in denial about these developments; so much so that Education Secretary Charles Clarke feels he can describe the tests as having a clear moral purpose, thus implying that the rest of the UK is immoral!
Ministers are also in denial about the evidence. The Government's own research review on high stakes tests found that they encourage transmission teaching, damage lower-achieving children's self-esteem and lead to a narrow curriculum.
Cambridge university has concluded that primary teachers' own sense of creativity as well as the creative curriculum is being undermined. Our surveys confirm this.
In short, the current testing regime impedes high-quality teaching and constrains teachers' professional judgments in meeting children's needs.
Mr Miliband refuses to meet the National Union of Teachers. So much for serious debate. Even the limited key stage 1 trial has been prejudged. Mr Clarke's letter to primary heads says tests for seven-year-olds are here to stay.
David Miliband knows that the NUT is not balloting on teacher assessment.
Children's progress will continue to be checked. Rather than make wild and irrelevant accusations he really should listen.
Head of education
National Union of Teachers