Education Minister Michael Gove has threatened to ban the seminars that exam boards put on for teachers following an investigation into alleged "corrupt practices", write Claire Newell, Holly Watt and Robert Winnett at the Telegraph.
Chief examiners had "overstepped the mark" and undermined public confidence in the system, said Gove.
This comes in the wake of an investigation that saw exam board officials filmed advising teachers at £230-a-day sessions on what questions to expect and the exact wording that pupils should use, the Telegraph found.
The exam regulator, Ofqual, this week announced that a GCSE exam had been rescheduled from last month after it was uncovered that teachers were given inappropriate advice on the subject of information and communication technology while attending WJEC exam board seminars.
Mr. Gove thinks "large-scale" reform of the exam system is needed. He said:
"I am clear, and the public reaction proves, that they have overstepped the mark on what is felt to be an acceptable level of advance information.
"Providing teachers and students with too much certainty over which elements of the curriculum will be tested, or which questions will be asked, only serves to narrow the curriculum, lower standards and promote teaching to the test."
Stephen Twigg, the shadow education secretary, said:
"The report from Ofqual is further evidence that the Tory-led Government needs to get a grip on our examination system.
"It shows that one GCSE has been compromised, and there are concerns about another.
"We need to have confidence that there are not wider problems with the system. Employers, universities and parents want the reassurance that one GCSE or A-level has the same rigor as another."
Mr. Gove wrote to Ofqual and said it was important to "minimize the risk of errors in forthcoming exam sessions". It is thought he is considering a ban on these sessions, driving home the point that it was important to look at the exam rules in the short term to ensure they properly limited the information that could be given out.
"In the longer term, as we redevelop requirements for A-levels and GCSEs, I shall seek to ensure that there is sufficient âunpredictability' and rigor in those specifications to underpin public confidence that the exams are true tests of ability," he added.