Gaining three A grades at A level has become "embarrassingly easy", the head teacher of a leading private school has claimed.
Writing in Times Higher Education this week, Anthony Seldon, master of Wellington College, says that the current system of GCSEs and A levels is "in deep trouble" due to the introduction of "bite-sized modules" that have "encouraged the culture of regular resits until top grades are attained".
"The content has been getting lighter, the examinations more susceptible to intrusive teacher and exam-board influence," he adds.
He also dismisses the A* grade, introduced two years ago to "toughen" the A level. He claims it has merely "made schools play the exam system in an even more sophisticated way".
Mr Seldon accuses schools, exam boards and successive governments of covering up the problems, with schools unwilling to "break their cosy oath of omertà about A levels".
Addressing vice-chancellors, he says: "The three A grades that your departments are asking for your top courses are acquired more through rote learning than thinking."
He adds: "GCSEs and A levels are in deep trouble and we need you to stand up and say so if your universities are to recruit students who can think independently and love knowledge."
Mr Seldon urges vice-chancellors to speak up for the International Baccalaureate (IB), which he claims is "the jewel in the crown of British education". However, "students at my school and elsewhere increasingly believe that the IB receives unsympathetic offers from some universities", which is having a direct impact on the number opting to sit the exam, he writes.
He concludes: "I plead with you to become active supporters of the IB at both the diploma and 'middle-years' level (which is the alternative to GCSE) and to adjust offers for IB students in line with leading universities abroad [that] acknowledge and reward fully the IB's intellectual challenge and depth."
David James, director of IB at Wellington College, said top universities were asking students to achieve more than 38 IB points - the equivalent of A*AA at A level.
"We are seeing growing numbers of 40-point offers," he said. "Some like the IB because they can ask for 40 or 42 points - you can't do that for A levels."
Meanwhile, tariff points should be phased out by the Universities and Colleges Admissions Service, a Ucas review unveiled on 9 February recommends.
It calls for their "gradual withdrawal" when setting entry requirements and making offers.
Instead, it proposes, all higher education offers should be grade-based.
Many universities have already stopped using the Ucas tariff-point system, which compares A levels with about 1,400 level-3 qualifications, including the IB.
The review suggests the creation of qualification information profiles for each course to apprise students, schools and admissions tutors.
A consultation is under way until 16 April, with a decision on the plans expected in June.