Hundreds of GCSE, AS and A-level results have been re-graded after errors were made in exam marking.
The OCR exam board said it apologised "unreservedly" for the mistakes, which were made by examiners, and insisted that action had been taken.
In total, 98 GCSE, 285 AS-level and 50 A-level results, were revised upwards after being re-marked.
The errors came to light in the autumn and were due to "human and process errors by a minority of examiners", the board said.
Schools and colleges with affected students have been told, OCR said, and they will pass on the results to their pupils.