Exams regulator Ofqual has launched an inquiry into the AQA exam board after it emerged that around 600 of this summer’s GCSE and A-level papers were incorrectly marked. Some students who sat exams got lower grades than they should have, Ofqual said. It affects about 150 A-level students, 290 AS students and 190 GCSE pupils. Ofqual chief executive Isabel Nisbet said: “This is a very serious matter.”