Nearly two thirds of parents who expressed a preference want an immediate independent investigation into this year's GCSE marking, a TES-commissioned poll has found.
The results came as an unprecedented alliance of head and classroom teacher unions, elite independent schools, local authorities, academy chains and FE colleges said it had lost confidence in regulator Ofqual, over its handling of the English grading controversy.
Last Friday the organisation said there would be no re-gradings of English GCSEs despite large shifts in grade boundaries which meant that many pupils who would have achieved a C if they had taken the qualification in January ended up with a D because they waited until June.
But the alliance says Ofqual should not investigate an affair it was involved in and wants an independent inquiry into a "transparently unjust procedure".
The poll of a representative sample of 1,000 parents with school aged children suggests that most agree with the alliance. Of the 751 who expressed an opinion, 65 per cent said the Government should sanction an immediate independent investigation.
Russell Hobby, general secretary of heads' union NAHT said: "We need an inquiry and we need it urgently: jobs and college places are on the line. How can we persuade young people of the value of education when the outcomes are so arbitrary?"
And Christopher Ray, Headmasters' and Headmistresses' Conference chairman agreed. "The verdict of Ofqual's initial report and the reasoning to support it fall well short of answering the questions raised in the minds of schools and pupils," he said.
In a separate development, the Commons education select committee has revealed that it will question heads' leaders, Ofqual and education secretary, Michael Gove, on the affair early next week. But it is yet to decide whether it will report on the issue.
Brian Lightman, Association of School and College Leaders general secretary said: "The row is essentially about fairness. It is wrong for pupils to be graded differently for the same exam."
The alliance also includes the Specialist Schools and Academies Trust, the National Association of the Teaching of English and the Girls' School Association.
An Ofqual spokesperson said: "We want to fully understand the concerns being raised by teachers, head teachers and their organisations about GCSE English.
"That is why we have been working hard over the past few days to meet many of them, listen to their views and share evidence.
"Their views and evidence will inform our thinking and investigations as we continue our work."