Paul Whiteman, general secretary of school leaders’ union NAHT, said: “The return to assessment via exams next year raises questions about how these will be graded. This year many students will have been able to demonstrate higher levels of attainment through shorter assessments taken throughout their course than in an exam on one particular day in June and so higher grades have been achieved overall.

“But suggestions of a move to numerical system are unrealistic. When GCSE grading changed, there were new specifications introduced and it took four years from the first teaching of those, to the point where all GCSE’s received numerical results. There is an opportunity here for government and Ofqual to review the current system’s reliance on terminal exams and grading by comparable outcomes. This requires meaningful consultation to ensure the fairest system for students.”