Consultation on the review of 16-19 qualifications officially ends today.
Sir Ron Dearing's review of post-16 qualifications has revealed widespread support for the principle of a new national certificate - but sharp disagreement over the form it should take.
There were 400 submissions to the review - consultation over which officially ends today. Sir Ron, who chairs the School Curriculum and Assessment Authority, held more than 100 meetings.
The most controversial option is a baccalaureate-style award for students who would select courses from a range of "domains" - such as arts, humanities and sciences.
The National Association of Head Teachers has proposed that all post-16 students follow a compulsory baccalaureate-style curriculum. Sir Ron's suggested model would be voluntary.
Supporters of the baccalaureate proposal say it will ensure students study more subjects, but college groups say Sir Ron's format is +elitist and that the broadening of studies would be spurious.
Sir Ron - whose review was commissioned in April by Gillian Shephard, the Education and Employment Secretary - has also sought views on two other models.
The first would mean "badging" existing qualifications to denote foundation, intermediate or advanced level. The second would reward those reaching the national target of two A-levels or the vocational qualification equivalent.
Sir Ron's third model - the "depth with breadth" option - is a clear front-runner but the most contentious because it introduces the concept of "domains". These are four groupings of subjects: maths and science; humanities; social sciences; and modern foreign languages.
Sir Ron has used a discussion model of a certificate with 24 sections or units comprising A-levels in history and physics, "new" AS-levels in maths, psychology and English, plus core skills of communications, numeracy and IT. He has also floated the idea of a six-unit, A-level-sized, general national vocation qualification being part of the mix. The NAHT would include one area studied in depth, three other subjects and core skills.
Sir Ron said: "We're told repeatedly that we are going to have to change careers several times in life, so we need to think whether in addition to the normal specialisation routes we need to give youngsters the opportunity to have breadth with depth as a preparation for a broad non-specialist career."
Qualifications based on "domains", such as the International Baccalaureate, compel the student to choose from more than one domain, with a combination of "main" and "subsidiary" subjects.
Breadth is considered vital on the basis that 16 to 18-year-olds should be acquiring wide general knowledge and solid transferable skills, which hold their value as the nature of work changes.
The concept of "domains" appeared in the influential 1990 paper A British Baccalaureate, by the Institute of Public Policy Research. Three years later the National Commission on Education suggested a general education diploma for which students would select options from "core areas".
Domains are opposed by the Association for Colleges and by the Sixth Form Colleges Association. Judith Norrington, head of curriculum at the AFC, said: "We would be in danger of missing a huge opportunity to unify the curriculum if we had a certificate which is exclusive rather than inclusive. That doesn't mean everyone should pass, but it should be attainable by about half the age group."
But enthusiasts see domains as allowing specialisation in one or two subjects, with "balancing" studies and a large common core of knowledge.
The key areas of controversy are whether students should be forced into breadth and if the bac approach makes for an elite qualification attainable only by a minority.
Sir Ron clearly values breadth but suggests students should be allowed to specialise if they want to. By contrast, the NAHT is proposing a qualification in which "all students between 16-19 should, as a mandatory requirement, pursue a broad education".
Sir Ron says everything is still "up for grabs" and is sensitive to the issue of exclusiveness: "If you want something that's going to be coveted and sought, it's got to be rather demanding.
"But whether it is too heavy is an issue. Should it be four subjects, not five? I'm open-minded. You could have two levels - one certificate, one diploma, or you could have the one award with different marks - the higher the mark, the more you have of it. It's still no more than a concept we are debating."
The move to split advanced General National Vocational Qualifications is also a step away from academic exclusiveness because it would make vocational options easier to include in a mixed award.
Having GNVQs the size of A-levels - or even AS-levels - would make them easier to integrate into the system. This is the key move towards parity of esteem between academic and vocational qualifications.
The NAHT also wants to combine academic and vocational elements, asking students to choose one in-depth subject, three balancing ones and three core skills.
The AFC and APVIC lead the so-called "Group of Seven" associations, including the Headmasters' Conference and Secondary Heads Association, who ultimately want a single framework with one title, made up of many smaller units of assessment. Sir Ron says the number of subjects in the certificate could be dropped to four, while keeping breadth.
He added, however: "There's no point in me inventing something which the Group of Seven say is right and then the universities and employers saying it's not. And employers are definitely interested in breadth."
A Confederation of British Industry survey showed that 56 per cent of employers favoured - and only 20 per cent opposed - a "general education diploma", requiring certain essential subjects.
Sir Ron said that he would be talking to universities and employers about the alternatives. He has also said that he will accept submissions for another week despite the official deadline having passed.
Sir Ron intends to produce his final report by next Easter.