An independent school head teacher has called for a review of GCSEs and A-levels, saying confidence in the examinations was at an all-time low.
Dr Seldon says the exam system is not fit for purpose
Dr Anthony Seldon, head of Wellington College, called for an independent royal commission into the exams.
Dr Seldon said confidence was "leaching out of the system".
His comments come as the Cambridge exam board refines its alternative qualification - the Pre-U exam - for students aiming for top universities.
From 2008 the exam would involve studying three subjects over two years, with final exams and an extended essay.
The University of Cambridge International Examinations (CIE) has developed the Pre-U - first announced last October - in response to demand from teachers wanting to prepare students for higher education more effectively.
Speaking at a conference at Wellington College, Berkshire to debate the future of the public examinations system, Dr Seldon said it was not meeting pupils' needs.
His students will start taking the International Baccalaureate in 2008.
"Instruction is taking the place of education, instruction is squeezing out good teaching so we can't discriminate the intellectually gifted from the very well drilled," he said.
"Imagination is being lost. Confidence is leaching out of the system.
"We waited and waited until we jumped ship but who believes in the A-level anymore? It doesn't create the kind of measure universities want."
His words were backed by Steve Watts, admissions tutor at Homerton College, Cambridge.
He said that the linking of the AS-level results with final A-level grades was leading to "endless re-sitting in order to get higher marks".
"The current system doesn't offer us sufficient discrimination between the very good and the best," he said.
"The 'A' is too big."
The Department for Education and Skills said no exam system was "so tightly or carefully managed".
"The truth is that standards in our schools are rising year on year and we are getting better as a country at getting the best from our young people," a spokesman said.
"We recognise that, as more young people make the grade, we need to find ways of better differentiating between candidates.
"That is why we are taking forward a range of measures to both stretch our brightest pupils and help universities and employers choose between the best."
Dr Seldon's call for a review of the exams system follows an inquiry by the former chief inspector for schools, Sir Mike Tomlinson.
Sir Mike said GCSEs and A-levels should be replaced by a diploma, but ministers declined to implement his recommendations.