Most teachers want to see England's competing exam boards merged to create a single unified awarding body, a union survey suggests.
They believe the end of exam board competition would make for a more consistent, simpler and fairer system and would prevent schools from choosing the "easiest" papers, a poll by the NUT has found.
"Since they compete for 'customers' this motivates them to erode standards," one teacher said. "A single board, removed from political pressures with a rigorous system to maintain standards is required."
A total of 51 per cent of teachers who responded said they supported the creation of a single board, including 21 per cent who said they strongly supported the proposal.
Consolidation and merger of exam boards in England has resulted in just three boards offering A-levels and GCSEs.
But some believe the competition between the big three boards should be preserved because it encourages innovation, offers greater choice and helps to ensure that levels of service to schools are satisfactory.
About a quarter of the 215 teachers in the survey said they opposed the creation of a single board.
"Pupils and schools vary," said one. "Teachers and schools choose an awarding body they feel suits them and their pupils. Variety and choice is good."
John Bangs, NUT head of education, said the fact that a majority favoured a merger indicated a "very grave anxiety among our members".
"Because the exam boards are in competition with each other they fear that if they choose the wrong one they disadvantage their kids and that is something that (exams regulator) Ofqual seriously has to address," he said.
The survey indicated a serious lack of faith in Ofqual. Only 3 per cent of respondents said they had confidence in it.
More than half - 56 per cent - gave no opinion on the regulator. But a third said they had "no confidence at all" in it.
Reasons given included the regulator's quango status and claims that it was out of touch with reality.
"All of these bodies are too remote from the people who know about teaching and assessment - teachers," said one respondent.
The survey found that more than a third of teachers - 35 per cent - were not confident about the quality of exam marking, compared with 43 per cent who were.
The doubters included teachers who were or had been examiners or moderators for the exam boards.
"I examine for both A-level and GCSE," said one.
"(I am) more confident about GCSE but the question is the depth of knowledge of some A-level markers I have met in my travels."
Ofqual research has suggested a doubling in the proportion of teachers between 2008 to 2009 who thought the regulator was either very or fairly effective from 16 to 31 per cent, while 61 per cent had no opinion.