An exams watchdog report is calling for changes to maths A-levels after reforms were found to have made the qualification easier.
Earlier changes led to many pupils dropping out of maths A-level
A review in 2004 led to a "slimming down" of the exam's content, prompting teachers to say the A-level was easier.
But the Qualifications and Curriculum Authority(QCA) insists the reforms were only designed to counteract earlier changes which made the exam too tough.
Ministers insisted maths A-level remained a challenging qualification.
But university science lecturers have increasingly had to run remedial maths classes for undergraduates who lack the appropriate ability in maths.
The report, which evaluates participation in A-level maths, said there was a perception among teachers and heads of maths that the new specifications were easier.
This is backed up by an increase in the number of A grades awarded in the subject.
"The changes made to the design of the award have been made to encourage success," the report said.
This was a deliberate move by the exams watchdog, which was trying to undo earlier changes in 2000, which made the examination too tough for many pupils and hence put many off.
This had led to a drop of candidates of up to a quarter, the QCA said.
But in making the changes, the A-level exam now fails to stretch the brightest pupils, the report said.
"The majority of respondents to the large-scale survey did not think that the current A-level was sufficiently stretching for the most able," it said.
The authors said the A-level could not do the two things at the same time - i.e. stretch the most able and seek to widen participation in a traditionally difficult subject.
Examination experts needed to decide what the A-level was for before making further changes, it said.
It suggested one of two routes:
Head of the QCA Ken Boston said maths was one of the most challenging areas of the curriculum and one of his key jobs was to maintain standards year on year.
- Either to develop a qualification that can meet the needs of the "clever core"
- Or to have an exam which increases participation in mathematics but has an extra, supplementary qualification that can fully challenge the very able.
"To strengthen the A level in the future we aim to increase the level of demand by introducing greater stretch and challenge and rewarding the brightest with an A*. Assessment will be more holistic, more synoptic and will better reflect the sometimes different needs of higher education and employers," he said.
"More than almost any other element of the curriculum, mathematics is a nationally important priority."
Schools minister Jim Knight said: "Right now, plans are in place to stretch the brightest candidates even further.
"The new A-level, which is currently being piloted, will stretch the most able candidates with more open ended, less structured questions and the A* grade will ensure that exceptional attainment is recognised and students are better prepared than ever before to study maths at university."
Maths teachers pointed out however that although this was true for A-levels in general the maths specification has only recently been revamped and is not being changed again.