Ministers have ordered an urgent inquiry into England's exams system amid claims that examiners have secretly been advising teachers on how to boost GCSE and A-level results.
An investigation by the Daily Telegraph has found evidence of teachers paying hundreds of pounds a day to attend seminars in which senior examiners offer detailed advice on how pupils can score higher marks in papers.
In one case, the newspaper reported it had recorded a chief examiner informing attendees which questions pupils would face in their next exams, and telling them "we're cheating".
Education Secretary Michael Gove has ordered the exams regulator Ofqual to conduct an urgent inquiry into the allegations, which will report back before Christmas. In a statement, Mr Gove said that the revelations "confirm that the current system is discredited".
"I have asked Glenys Stacey (chief executive of Ofqual) to investigate the specific concerns identified by the Telegraph, to examine every aspect of the exam boards' conduct which gives rise to concern and to report back to me within two weeks with her conclusions and recommendations for further action," he said.
According to the Telegraph, teachers have paid up to £230 a day for seminars hosted by chief examiners during which they are given advice on the wording students should use to increase their marks. The examiner who allegedly told teachers which questions their pupils could expect to see in their next exams was said to have been recorded as saying "we're cheating".
The newspaper said its investigation had exposed a system of exam boards competing to win business from schools.
In his statement, Mr Gove said: "As I have always maintained, it is crucial our exams hold their own with the best in the world. We will take whatever action is necessary to restore faith in our exam system. Nothing is off the table."
An Ofqual spokesman said: "We have made it clear that this is an issue of significant interest to us. Exams must be run in a way that is fair and open to all candidates.
"We have introduced new regulations to tighten up the requirements awarding organisations must meet to make sure their commercial activities do not impact on the standards and integrity of qualifications. Failure to meet these standards will result in regulatory action."