The head of qualifications regulator, Ofqual, has written to all awarding organisations following a series of errors in AS-level exam papers. A maths question from OCR, biology question from Edexcel and a business studies question from AQA all contained mistakes worth up to 11% of the marks. Ofqual has discribed this as “disappointing and unacceptable” and has told awarding organisations to carry out extra checks.