At least 143 secondary schools are at risk of being labelled as failing after they were affected by the GCSE English grading fiasco, it has been suggested.
Schools could be forced to turn into academies and headteachers' jobs jeopardised if they fall below the Government's GCSE floor target in the wake of the crisis, the Association of School and College Leaders said.
The warning came as Ofqual chief Glenys Stacey admitted that she would have forced one of England's biggest exam boards to alter its GCSE English boundaries to avoid grade inflation.
The regulator has the power to direct grade boundary changes and would have done so if Edexcel had not revised them, she told the Commons education select committee. As Ms Stacey gave her evidence, ASCL raised concerns about the numbers of schools which have seen their overall GCSE results drop due to the English grading crisis.
This year, secondary schools in England will be judged as under-performing if less than 40% of pupils get at least five Cs, including English and maths, and if students are making below national average levels of progress. Those that fail to meet the target face being taken over and turned into an academy.
ASCL said that 143 schools had told them that their results had left them below the benchmark when they had expected to be above it. In total, 730 schools had responded to the poll, with 641 saying that their results had been lower than expected this year. Of these, around 500 had said the main reason for this was GCSE English.
ASCL general secretary Brian Lightman said the grading fiasco "could cause enormous reputational damage to these schools, and even cost school leaders and teachers in these schools their jobs, which would be a gross injustice in view of the way these results have come out." He added: "These are schools that have been improving and doing all kinds of things to raise standards, and they now find themselves in a completely unexpected position."
Mr Lightman said that the union had been in talks with the Department for Education and Ofsted about the issue. "If any of our members are challenged on the basis of results like this, which we think are unfair, we will do everything we can to defend them."
Leaked letters showed that Ofqual pressurised Edexcel to alter its GCSE English grade boundaries just two weeks before results were published last month. Appearing before the Commons education select committee, Ms Stacey was asked what Ofqual would have done if Edexcel had stuck to its first response to the regulator, and insisted that its proposed grade boundaries were fair.
The leaked correspondence, seen by the Times Educational Supplement (TES) show that Ofqual wrote to Edexcel on August 7 amid concerns that there would be a rise in C grades, calling on them to act quickly to produce results that were closer to predictions for the subject. The board responded a day later, saying it believed its proposed grade awards were "fair" and there was no justification for further changes.