Ofqual chief regulator Sally Collier has resigned in the wake of the A-level and GCSE results U-turn in England.
She will be temporarily replaced by her predecessor Dame Glenys Stacey, the exams regulator said.
The news comes after almost 40 per cent of A-level entries in England were downgraded due to an algorithm, which was later dropped and students were given teacher assessed grades instead.
The algorithm was more likely to downgrade pupils from disadvantaged schools and was accused of being classist.
Last week Education Secretary Gavin Williamson tellingly did not back Ms Collier in an interview with LBC.
Station host Nick Ferrari asked: “If you have confidence in Ofqual boss Sally Collier, please speak now.”
Mr Williamson replied: “I’ve worked with everyone in Ofqual and Ofqual are going to do everything that they can.”
In a statement, Ofqual, the regulator of exams in England, said: “The Ofqual board has agreed temporary support arrangements with Ofsted to support the ongoing work on this summer’s GCSE, A-level and vocational qualifications, including appeals and autumn exams, and preparations for next year’s exam season.
“The chief regulator, Sally Collier, has decided that the next stage of the awarding process would be better overseen by new leadership.
“The Ofqual board supports Sally in this decision, and thanks her for her leadership and service over the past four years, which has included overseeing the successful introduction of an entirely new set of GCSEs and A-levels, and a new grading system.
It continued: “As a result, the Ofqual board has asked Dame Glenys Stacey to assume a temporary leadership role as acting chief regulator until December 2020, having previously served as chief regulator between 2011 and 2016.
“She will be supported by a new committee of the Ofqual board, which will include one or more of the current Ofsted board members.
“This new committee will be chaired by Amanda Spielman and will oversee the work of Ofqual to the end of the year. Roger Taylor remains Ofqual chair.
“If required, Ofsted will also provide additional staff to support Ofqual during the autumn, as they have been supporting other Government departments through the summer.
“Taken together these arrangements will ensure that Ofqual has the extra capacity, support and oversight it needs both to tackle the remaining issues from this year’s awarding process and to ensure that next year’s arrangements command public confidence.”