The contentious proposal would see a market structure introduced, which would allow any organisation to set up as an exam board, subject to accreditation by the QCA.

The elements of boards’ responsibilities, from writing the syllabus to marking papers and setting grade boundaries, would be handled separately by different bodies.

The model being suggested seems to mimic public utilities where some companies generate gas or electricity or provide telephone networks while others specialise in selling services to the consumer.

The plans, which were put forward by Sir Anthony Greener, chairman of the QCA, have yet to be finalised, but they would reverse decades of change.

The number of boards offering academic qualifications has been cut from more than 20 in the 1970s to only three now, as successive governments have sought to standardise courses and qualifications.

The proposal has been discussed within the authority, but not within the exam boards. It will face fierce resistance from those opposed to more private involvement in education. Although more than 100 bodies currently offer vocational qualifications, traditionally the government has tightly controlled the number of boards offering academic exams such as GCSE and A-level.

However, Ken Boston, the QCA’s chief executive, has already raised the issue of deregulation. In a speech at the authority’s annual conference last October, he presented it as one of several options.

He asked whether boards might compete “on a fully commercial basis”. This would end the concept of the “common standard” which ensures that one board’s qualification is worth the same as another’s.

Qualifications such as the International Baccalaureate and the A-level would compete to attract schools, who could also use exams “imported from abroad”.

Radical change, Dr Boston said, was essential, in order to restore public confidence in the system following last year’s A-level re-grading controversy.

Sir Anthony has had a low profile since his six-month appointment as chairman following Sir William Stubbs’ resignation last October. His tenure was extended quietly for another year in April. Unlike Sir William, he receives no salary in the post.

A businessman - he is chairman of the University for Industry and deputy chair of British Telecom - he was an enthusiastic backer of communications giant Pearson’s controversial take-over of the exam board Edexcel earlier this year.

He was in the United States this week and could not be reached for comment.

Dr Boston said: “I have said many times that changes are needed.

We have been looking at a number of proposals for long-term reform, but it is important to stress that work that has been done since last summer has considerably strengthened the system. I have confidence in the awarding bodies to deliver this year, and we will be working closely with them and others as we shape the way forward.”

John Bangs, head of education at the National Union of Teachers, said: “I would be concerned about anything which raises the threat of examinations being skewed by the demands of private companies.

“The three exam boards have learnt a lot through the difficulties of the past three years. The idea of going ahead now into a market-based system would throw all that experience into question. Teachers won’t want this: it would be just another disruptive change.”

Another suggestion by Dr Boston last October, was to give the QCA greater independence from government, a suggestion effectively blocked this week by ministers in their response to the education select committee (see page 8).

A further option was a single exam board, though former chief inspector Mike Tomlinson’s report on the A-level furore rejected that idea.