A two-tier maths GCSE is being developed by the Qualifications and Curriculum Authority and will be piloted in schools this year.
Last summer, senior examiner Jeffrey Robinson criticised the current three-tier structure that allows a candidate to earn a grade C with a score of just 18 per cent.
Currently, teenagers sit either a higher paper covering grades A* to C, an intermediate paper (B to E) or a foundation paper (D to G).
The questions are banded by ability: in the higher paper a quarter of questions will be aimed at A*-level students, a quarter at A-grade students, and so on. Students only need to get two-thirds of the marks in their ability band. This explains why a candidate can get a C with such a low mark: they only need to get two-thirds of the "C-grade" questions right, or two-thirds of 25 per cent - 18 per cent.
Mr Robinson's claims of grade inflation were dismissed by exam boards, the Government and the QCA, which hastily published a five-year study concluding that the maths GCSE had got harder.
But the investigation into a two-tier alternative is an indication that the three-tier structure, in place since 1994, is not ideal.
There is a question mark over whether the same grades awarded for different papers are comparable. Candidates can get a B on the intermediate paper but miss a significant amount of the content that a student getting a B in the higher paper would cover.
Mr Robinson claimed pupils can do well without knowing any algebra. The foundation paper also risks demotivating pupils because they can only achieve a D.
The new structure would involve three papers, one covering A*, A and B, another C and D, and the final E, F and G. More able candidates would sit the top two papers and less able candidates the bottom two.
A QCA spokesman said the proposals were in response to changes to the key stage 4 maths curriculum and were in the pipeline long before Mr Robinson's comments. "Since 2000, two programmes of study in maths have been available to schools. The pilot will explore if two tiers would fit better."
Doug French of the Mathematical Association said the structure was far from perfect. "An intermediate grade C can be achieved (despite) studying significantly less algebra than is needed for a higher grade C. This can cause problems if the pupil goes on to A-level."