Two senior examiners apologised today after appearing to tip off teachers about how they could secure top grades for GCSE students.
Paul Evans, of the WJEC board, and Steph Warren, of Edexcel, said they regretted "inappropriate" comments made to undercover reporters from the Daily Telegraph.
But they insisted they had never revealed details of questions due to be asked in forthcoming exams.
Another examiner caught up in the sting, Paul Barnes of WJEC, said he had been "misrepresented" by the newspaper and denied breaking any rules. All three have been suspended while investigations take place.
The developments came as the Commons Education Committee took evidence following the expose last week.
The MPs heard that Edexcel was "deeply concerned" about the revelations, and "systems and processes" were being strengthened. But representatives from AQA and OCR defended their existing safeguards. WJEC said it was satisfied no exams had been compromised.
Chief examiners Mr Evans and Mr Barnes were filmed taking a seminar for the WJEC GCSE history course last month.
Mr Evans reportedly spoke about the "cycle" of questions used by the board. "We're cheating, we're telling you the cycle," he said.
When someone pointed out this information was not in the course specification, Mr Evans is said to have replied: "No, because we're not allowed to tell you."
A teacher asked whether they had understood correctly that there would be no question on Iraq or Iran next year. Mr Barnes said: "Off the record, yes."
Speaking to the cross-party group of MPs this morning, Mr Evans said the intention of the seminar had been to "inform teachers about the course, take them through the lessons learned from the results of examinations in the past, with a view to assisting their teaching in teaching their pupils for future exams".
He insisted he had merely been indicating that information about compulsory questions was given in the teaching guide, and not in the specification.
"My reference to the word cheating was an inappropriate term to use," he said.
"At no stage during the seminar did I reveal any specific questions that were to be asked in the 2012 exam, or in any subsequent exam.
"Nor did I breach any confidence regarding the examination process itself."
Mr Barnes told the committee that his "off-the-record" comment was a "throwaway figure of speech".
"As far as I am concerned there has been no breach of my duties in terms of (as) an examiner," he said.
"As a member of the WJEC I have always tried to uphold the very high standards of the exam board."
He added: "I really, truly believe that I have been misrepresented by the Daily Telegraph."
An undercover journalist posing as a teacher who was considering using Edexcel's GCSE geography tests approached Miss Warren at another seminar.
She reportedly told them that "you don't have to teach a lot" and that there was a "lot less" for pupils to learn than with rival courses.
Miss Warren added that she did not know "how we (Edexcel) got it through" the official regulation system for standards in GCSEs and A-levels.
Giving evidence today, she claimed she did "not even recall the conversation".
"I had had a really exhausting day of training, one of the most difficult training days of teachers that I have ever done in my career," she said.
"I do regret the comments I made which created the impression that the content of the specification is less and therefore the specification is easier than other geography GCSEs.
"I did not say that the specification was easier."
She went on: "My comments were made in the heat of the moment after a long training session. I do not think that the specification has less content.
"I do not know why I made the comments. I have not read the other awarding bodies' specifications or even Edexcel's other geography specifications.
"So I have no basis on which to compare them. It was an inappropriate comment that I deeply regret making. I am only human and we all make mistakes."
Rod Bristow, president of Pearson UK - which owns Edexcel - said the sting had "exposed that the things we have been relying on so far are probably insufficient".
Seminars would now be routinely filmed and published, he indicated.
"I think the events that we have seen mean that we do need to strengthen the systems and processes that we have," Mr Bristow added.
AQA chief executive Andrew Hall said such seminars - which cost up to £230 to attend - were run at a loss.
"We have been aware from time to time that the odd examiner was sometimes acting in an inappropriate way. We have a malpractice team and we investigate it," he said.
"But widespread? No."
Mark Dawe, chief executive of OCR, accepted there was an "enormous amount of pressure on the system".
"But we believe we have procedures in place to protect the integrity of our exams," he added.
He said the UK had one of the most transparent exam systems in the world.
Gareth Pierce, chief executive of WJEC, insisted the revelations had not affected the integrity of any of their GCSE exam papers.
"We are absolutely confident there has been no compromise at all," he added.
Glenys Stacey, head of regulator Ofqual, said she had been "surprised" by the examiners' comments.
"I was aware of concerns about what happens in seminars," she said. "I have been sufficiently concerned about what I have heard to declare it as a priority for me and did so about a month ago.
"But I was surprised at the exact nature of what I saw," she added.
A review had been launched to make sure there was not "any sniff" of concern that exam papers had been compromised, she added.
She also suggested that whistleblowers in the education sector should be given more protection.