The head of England’s exams regulator, Sally Collier, has quit after thousands of students’ marks were downgraded for exams they were unable to sit.
Ofqual chief Ms Collier has been under fire for a controversial algorithm which changed GCSE and A-level marks, making them unfair, according to heads.
It also led to many A-level students losing university places they had been offered, and a crunch on degree places.
Education Secretary Gavin Williamson thanked her for her commitment.
Exams for GCSE and A-level students were cancelled in March, just before schools were closed by the government, when the nation was in the grip of the coronavirus pandemic.
A system to ensure pupils could still get their grades was drawn up by Ofqual which involved teachers and schools predicting grades for their pupils from a whole range of evidence
These were then sent to the exams regulator to be moderated.
The now discredited algorithm used information on schools’ past performance to moderate the grades, drawing complaints that pupils were being judged on the efforts of the predecessors.
Scotland, which used a similar system, rowed back on the arrangement after it became apparent that many bright but disadvantaged pupils were downgraded.
Scotland’s education secretary John Swinney announced a switch to teacher-assessed grades and results were re-issued.
But it was not until two weeks later that his counterpart in England, Gavin Williamson, decided to revert to what are known as centre-assessed grades.
This meant that hundreds of thousands of A-level results had to be re-issued and GCSE results were rushed through to schools to be released three days after the government U-turn.
And hundreds of thousands of the BTec students have still not received their grades after the exam board, Pearson, made a last minute decision to re-grade.
The previous regulator, Dame Glenys Stacey, has been asked to step in.
She will run the next stage of the exams process on a temporary basis until December, the Ofqual board said, along with the chief of Ofsted, Amanda Spielman, who previously worked at Ofqual.
Mr Williamson said: “Following Sally Collier’s decision to step down as Ofqual’s Chief Regulator, I’d like to thank her for the commitment she has shown to the role over the last four years and wish her well for the future.
“I welcome Ofqual’s announcement that Dame Glenys Stacey is to assume a temporary leadership role as acting Chief Regulator and also the new internal governance arrangements put in place with Ofsted support.
“This will make sure Ofqual can fully focus on the important functions it must deliver as the independent regulator for qualifications, examinations and assessments in England.
“Moving forward, my department will continue to work closely with Ofqual’s leadership to deliver fair results and exams for young people.”
Association of School and College Leaders general secretary Geoff Barton said: “This move follows the failure of the statistical model that led to this year’s grading fiasco, but the fault is not hers alone.
“Ministers have questions to answer over the extent to which they scrutinised and challenged the methodology and reliability of the statistical model, particularly given the enormity of the task and the importance of getting it right.”