Schools and universities have refused to recognise the existence of "softer" A-levels, despite a report released earlier this week claiming pupils were losing out on places at top universities for studying "non-traditional" subjects.
The document, The Hard Truth About Soft Subjects, published on Monday, showed that leading universities favour more traditional subjects, such as maths and science, over "softer" A-levels, such as media studies, photography and law.
The research, compiled by a right-of-centre think tank, the Policy Exchange, also claimed that the universities it analysed were "failing" pupils from comprehensive schools - where "non-traditional" subjects are more widely offered - by not making their preferences sufficiently explicit.
The report said only two of the 27 universities that it analysed, Cambridge and the London School of Economics, made their requirements clear by publishing a list of "non-preferred" subjects.
The report's author, Anna Fazackerley, went so far as to say many universities were purposefully keeping their preferred subjects to themselves, and that pupils were being misled by opting for the more professional-sounding A-levels, such as law.
Ms Fazackerley said: "It is particularly scandalous that top universities are keeping quiet about their disapproval of 'professional' A-levels, such as law, accounting and psychology. These subjects are very likely to trip up pupils because they sound serious and impressive, but search admissions websites and the warnings just aren't there.
"How can pupils be expected to know that having law A-level may rule you out of a law degree?"
The report analysis shows that 10.6 per cent of A-levels taken at school are in what it calls "soft arts", which include art, drama and film studies, while 6.4 per cent are in "soft professional", such as law, accounting and business studies. Less than a quarter of A-levels taken are in traditional maths and science.
However, more than a third of all accepted A-levels from the 27 universities canvassed are in these traditional subjects.
Scoring particularly low was UCL, which had only a 1.1 per cent intake of students with professional subjects, such as law. The university refused to acknowledge that it discriminated between "soft" and "hard" subjects but did say that when it came to courses such as law, it was "better to start from scratch".
Speaking to The TES, the vice-provost, Michael Worton, said: "We don't assign any weighting to particular A-level subjects, although we do have two exceptions, which are critical thought and general studies, which we don't acknowledge when added as AS-level.
"But many of our courses specify individual requirements when it comes to subjects. Students need to show a balance when it comes to their chosen subjects, and, as a research-led university, we look for academically strong students."
Mr Worton added: "The Policy Exchange research takes little account of the degree programmes at universities. Many of our students have strong credentials in maths and science because that's the type of course we offer. But overall, we just want students who achieve high grades."
The Department for Children Schools and Families and the major examination boards, such as the OCR, said they did not recognise softer or harder A-levels, and both said they were confident that all A-levels were "rigorous and robust".
But evidence revealed in a report released by Durham University's CEM Centre in the summer suggests otherwise. The document, Score, showed certain subjects were marked "more leniently" than others. "I wouldn't call subjects 'softer' but perhaps 'more leniently graded', whereas others are more harshly graded," said Peter Tymms, director of the CEM Centre.
"Points are ascribed for A-levels, and law is seen as a little bit easier; it is generally a quarter of a grade easier than if a student is doing physics, which is three-quarters of a grade harder."
According to the Score report, psychology, geography and politics are regarded as "average" subjects when it comes to grading, and maths, science and modern languages as the hardest.
Mr Tymms added: "The report puts A-levels in order of difficulty, but universities should take into account the relativity of different subjects. If a student has A grades in drama, fine art and sociology, that doesn't mean a university should just dismiss them."
The report released this week calls on all universities to publish lists of their preferred subjects, to allow teachers to give pupils better advice. Many universities claimed this would be impractical, as it would prove too difficult to get a single view across all faculties.
But school teachers believe it is bad for a university's public image to list subjects that it does not prefer. Ken Warman, principal of Brook House Sixth Form College in Hackney, east London, says certain subjects require different skills, and he pointed the finger at universities for failing to offer schools clearer advice.
"Maths and media studies require different thinking," Mr Warman said. "Just because one requires course work and the other, exams, doesn't mean one is easier.
"When you look at accounting nationally, it has a very low pass rate, so surely that doesn't fit with this idea that it is a softer subject."
Mr Warman added: "Universities need to be explicit when it comes to entry requirements. If they don't say what they are after, how are we supposed to know?
Cambridge is one of the few universities to issue a list of "preferred" subjects. Its director of admissions, Geoff Parks, knows the criticisms that come with such a list.
He told The TES: "You take a lot of flak for publishing such a list - you put your head above the parapet. But another reason why universities don't do it is because, unlike Cambridge, some university courses are selective whereas others are recruiting, and it can be a very difficult balance to strike."
Mr Parks says the advice pupils receive at schools varies wildly; more time needs to be allocated by teachers: "At some recruitment events, the conversations I have had show students have been given the right advice and chosen the right combinations of A-levels.
"But I have spoken to students who have not been given very good advice at all, where I end up having heart-breaking conversations.
"Many universities have different criteria but teachers do need to dedicate more time to give advice."
Cambridge will be issuing literature by next Easter that gives advice to students a year earlier. The university said prospectuses arrive a "year too late", as Year 12 students have already chosen their subjects.
The Russell Group of universities said the information its universities provide for potential students on the qualifications and knowledge they need was improving. The director-general, Dr Wendy Piatt, said universities "now offer clear recommendations on the A-level subjects and packages of A-levels (or equivalent) which would give the candidate the best grounding for a particular course and, in some cases, which would be less ideal."
SOFT AND HARD: A NEW LOOK AT A-LEVELS
The Policy Exchange report divided the "softer" A-levels into "soft arts" and "soft professional" subjects.
Soft arts included: art and design; fine art; photography, media studies, drama, film studies.
Soft professional included: accounting, business studies, law, sociology, psychology.
Hard subjects included: biology, chemistry, physics, maths, further maths, modern languages, geography, history, economics.
The subjects that universities prefer
Biology, chemistry, further mathematics, mathematics and physics comprised close to half of all accepted A-levels for Bristol University (49.8%) and University College London (46.9%).
75% of all A-level examinations are taken in non-selective state schools but 96% of law and 93% of media studies A-level entries are in these schools.
Only Cambridge and the London School of Economics publish lists of "non-preferred" subjects.
More than three times as many economics A-levels were accepted at Nottingham University than sociology, or dramatheatre studies.