Exams regulator Ofqual was accused of losing control of the examination system by headteachers today.
They reacted furiously to yesterday's final report on this summer's GCSE English grading fiasco which accused teachers of overgenerously marking their pupils' work to gain them a top C grade pass.
The report, though, acknowledged that the new English GCSE had been poorly designed - by giving 60 per cent of the marks to controlled assessment of coursework and allowing pupils to do coursework after being give the grades for their written exam.
Russell Hobby, general secretary of the National Association of Head Teachers, said today that teachers should not be made the "scapegoats" for faults in the examination system."
He added that the "punitive and single-minded focus on C grade exam passes" as a result of the pressure of league table measurements deserved blame for the crisis.
"If your elected government tells you this is the right thing to do (improver C grade passes), if your performance is measured on it and if you are sacked for failing to achieve it, you have no choice but to do it," he said.
However, he added that Ofqual was "wrong to sacrifice the interests and prospects of students" by raising the grade boundaries for pupils who sat the exam in the summer.
"Ofqual lost control of the examination system and failed to provide the necessary warnings," he said. "Poorly designed exams shouldn't have been given to students in the first place.
"Young people are the victims in this, not of over-zealous marking but of a regulator which lost its grip and a system badly in need of repair."
Kevin Brennan, Labour shadow schools minister, added: "Pupils shouldn't be punished for this shambles. Michael Gove and David Cameron look utterly incompetent and out of touch.
"The Government has the power to sort this out - as has already happened in Wales (where students have had their papers re-graded)."
He urged Mr Gove to set up a full independent inquiry into the affair.
Mr Gove has always insisted he put no pressure on Ofqual or the exam boards over grading. His department said he was conducting a review of accountability through the league tables.
Ofqual and two exam boards (the Assessment and Qualifications Alliance and Edexcel) are facing legal action by headteachers, pupils and local authorities over the affair.
They are seeking a judicial review of the decision not to re-grade students' scripts.