The E-level - harder than a GCSE but less difficult than a full A-level - is entering its second year. The exam, still in its pilot phase, has been commissioned by independent schools eager to meet the needs of less academic pupils who don't want to follow a vocational route.
Vivian Anthony, general secretary of the Head Masters' Conference, says that at present there are no alternatives to A-level for this group.
"They can retake GCSEs, but our general experience of that has been most discouraging. They are effectively disenfranchised."
As a signal of its serious intentions, and frustrated by the Government's reluctance to embrace post-16 reform, HMC joined forces with the Northern Examinations and Assessment Board (NEAB) two years ago to develop and pilot the Certificate of Extended Studies or E-level.
Although only moderately successful so far, the pilot has underlined the needs of two distinct kinds of students.
First, the less academic, grade C and D achievers at GCSE who would be daunted by A-level and who, in an increasingly diverse and competitive post-16 market, might be tempted to go elsewhere - a sixth-form college or tertiary, for example.
The second group are those seeking breadth; high-flying A-level students wanting to keep up their French, say, or to get a qualification at 17 in compulsory religious education.
The demand for a new kind of exam provides hard evidence that, even in the private sector, the A-level gold standard is frustratingly narrow.
Last week HMC, which represents many of the country's major public schools, expressed their views to Sir Ron Dearing, chairman of the Schools Curriculum and Assessment Authority, whose review of 16 to 19 education is currently underway. Their message was that unless or until the Governmment comes up with something better, HMC is committed to the E-level.
Reluctant to embrace GNVQs until they have been thoroughly tried and tested, many independent school heads have been pushing for an intermediate qualification for some time.
Effectively they wanted something equivalent to half an A-level, but cut horizontally rather than vertically as with the present AS-level.
Pupils taking AS still have to reach the full A-level standard, even if the content is reduced, but an intermediate qualification would represent the first and less difficult half of a two-year developmental A-level. "It would be roughly equivalent to the first year of sixth form," says Mr Anthony.
In 1993 E-levels in English, French, mathematics and physics were piloted in a mixture of independent, state schools, sixth-form and FE colleges. History, religious studies and biology were added to the list in the following year.
The qualification combines a mixture of coursework and final examination and is graded to pass, merit and distinction. A distinction, for example, is "demanding something higher than would be achieved by a grade A candidate at GCSE", according to an NEAB spokesman.
The final stage of the three-year pilot ends next June; if E-levels continue they are only likely to be taken up by independent schools because, without approval from the Government via SCAA, they hold no currency in state schools. FE colleges have more freedom to take the exams they wish, but traditionally they are more accepting of vocational qualifications.
Teething problems aside - syllabuses came out too late for curriculum planners in the first year and some FE colleges have complained that its administration is burdensome - the E-level has been generally well-received. It has not, however, been used in the way it was intended.
By far the largest take-up has been for French. Up to 375 candidates were entered in the first year, a figure which has more than doubled this year, compared to little over 40 in each of the other subjects.
Although E-level is aimed at middle achievers in GCSE, pupils undertaking French were mainly those with top grades, whose schools used E-level as a way of broadening the sixth-form curriculum. Some schools, like Altrincham and Manchester Grammar Schools, who entered 86 and 55 pupils respectively, used E-level French as a stop-gap for their brightest linguists who took GCSE one year early.
Altrincham's head Bryan Purvis says E-level is a better preparation for A-level than GCSE - "it has been very successful in bringing on our more able linguists". Evidence of this success is reflected in the student numbers - 21 taking A-level French in the lower sixth "compared to the usual eight or nine".
Altrincham, which remains a state-run grammar school in Trafford, is now considering using E-level in other subject areas. "For example," says Mr Purvis, "our best scientists taking GCSE dual-award science could top up with an E-level, say, in physics."
Giggleswick, a North Yorkshire boarding school, is piloting an E-level in history as part of its sixth form foundation year. This is aimed at pupils in need of a broad, preparatory curriculum to A-level, GNVQ or employment.
The E-level is being offered alongside GCSE retakes and Certificate of Further Study courses, such as English for business or French for business offered by the Associated Examining Board, which have a more vocational flavour.
For HMC, the E-level is a sub-plot to a much wider issue. Dr John Moore, headmaster of the King's School, Worcester, and chairman of the organisation's academic policy sub-committee, believes that the modularisation of A-levels could pave the way for an intermediate qualification.
"If you got away from the premise that every module had to be set at the full A-level standard, that the exam was developmental, then you could set the first, say, three modules at a lower level of difficulty than the second three." In that way, the modules could be banked and accredited as achievement at an intermediate stage, leaving pupils free to decide whether or not to go on to the higher stage.
At present some students undertaking two years of A-level study get no return for their efforts.
Last year 20 per cent of pupils failed with N or U classifications at A-level. "For two years of work, they get a kick in the teeth, when most of them must have deserved something," says Dr Moore.
"Pupils with N grades will have passed some of the papers. It has to be an issue of social justice."
Some exam boards believe that modularisation of A-level helps less academic students who are better able to deal with a subject when it is broken down and examined in smaller chunks.
But HMC also believes that an intermediate exam, like E-level, could rightly be used to provide breadth for sixth-formers. A student could embark on five subjects at A-level, taking two of them only as intermediates.