By Mike Baker BBC education correspondent

Are the working-classes storming the ivy-clad walls of British universities or is the door still firmly slammed shut on all but a token few?

This question - which lies at the heart of the arguments over top-up fees - was highlighted by the latest university "league tables" based on student 'access'.

At first sight, they made gloomy reading for supporters of wider access. The top universities still seem to form a social, as well as an academic, elite.

Oxford and Cambridge take just 9% of their students from the lowest three socio-economic groups.

For most of the other leading universities the figure is below 20%.

Yet 40% of the population as a whole is designated to these groups.

The latest figures showed virtually no change on last year, leading some to conclude that the "widening access" door has jammed while still only slightly ajar.

'Middle-class nation'

But it may not be that bad if you look at longer term social trends.

Over the past 30 years or so, Britain has become an increasingly middle-class nation.

While the bottom three socio-economic groups may account for 40% of the population now, as recently as 1970 the figure was 90%.

At this rate of change, the percentage of working-class students in universities will eventually match their proportion in society as a whole.

In fact, the gap is closing. In 1970, students from higher social classes were six times more likely to get into university than those from lower classes. Now they are just three times more likely.

Are traditional universities socially elite?

So things may be getting better. That certainly is the view of a new survey of the state of education, just published by the National Commission on Education.

It makes the sharp observation that British universities are 'trying to do at breakneck speed what the USA did over the four decades following World War II".

In other words, trying to become a system of mass higher education.

It concludes that the universities are doing fairly well. On "access", it says Britain has one of the best records in the world, second only to Finland.

It also notes that drop-out rates remain 'astonishingly' low.

And, of course, it is not fair to lay all the responsibility for widening access on the universities.

Many youngsters have been put off the idea of higher education well before the end of compulsory schooling.

Discrimination

Nor, in fairness to the top universities, could they easily expand access without lowering entry standards.

At a conference on university admissions this week, this was put starkly by a representative of one "Russell Group" university.

His students, he admitted, were 'very Home Counties and bourgeois' but there was 'almost nothing' the university could do about it unless they discriminated against the independent schools on a 'big scale'.

At the same conference, run by the Social Market Foundation, the man in charge of the independent inquiry into university admissions made an interesting appraisal of what, realistically, can be achieved.

Professor Steven Schwartz said the '10 or so most competitive universities cannot do the job of widening participation'.

Whatever measures his task force comes up with, he accepted that while educational achievement is so strongly linked to social background, there is only so much universities can do.

However Professor Schwartz did indicate the sort of changes his task force might recommend early next year.

He is interested in the potential of additional tests to identify students with academic potential but who may not have done well in traditional exams.

Cambridge tests

These tests might include American-style SATs or the growing number of tests being piloted by British universities.

One new test, the Thinking Skills Assessment, already seems to be winning support at Cambridge.

It started as a "pilot" for under 300 applicants in 2001; this year over 1800 applicants are expected to take the test.

As yet, the TSA does not replace the traditional selection criteria and a full assessment of its role is not yet ready.

But Dr Robert Harding of the University of Cambridge Local Examinations Syndicate told the Social Market Foundation conference that admission officers liked the new test and were "voting with their feet'.

Moreover he hinted that the early research suggested that the TSA was better at indicating academic potential than either interviews or A-Levels.

If wider and fairer access to universities is to be achieved, this sort of additional test to measure applicant's potential may be needed on a much wider scale.