By Mike Baker BBC education correspondent

Whether you detest or admire the government's plans for higher tuition fees, you have to admit they are bold.

You might even say they were brave - in much the sort of way you would commend someone setting out to swim the English Channel on a freezing winter's day. You wouldn't want to be trying it yourself.

Tony Blair certainly cannot be accused of seeking popularity with the tuition fees proposal. Few seem to like it.

Indeed, a contest between those heaving behind him, and those digging in their heels to stop the Bill, looks like pitting a school 2nd XV against the England World Cup rugby team.

Just look at the respective "packs".

'Socialist principle'

On the opposition side are the Conservatives and the Liberal Democrats, 100 or more Labour backbenchers, the students, the lecturers' unions, many parents and some universities.

Meanwhile, the weight coming in on the government's side is fairly limited: the vice-chancellors of the elite universities and a sprinkling of newspaper leader writers.

Moreover, while there is a rationale behind the changes - even a socialist principle, according to the Education Secretary, Charles Clarke - the detail is so complex that ministers' job of explaining it is about as easy as teaching algebra to five year olds.

It does not help their case that the plans have been dubbed "student top-up fees", when that description is wrong on just about every count.

Will the government kick the doubters into touch?

Firstly, they are not paid by students, but by graduates.

Secondly, they are not "topping up" anything, since rather than being an addition to the current fee, the new deferred payment can be set anywhere from �0 to �3,000.

There appear to be few, if any, votes in it. So why is the government doing this?

Ministers argue that it needs to be done because, while universities do need more money, nursery education, schools and hospitals are ahead of them in the queue for any extra taxpayers' money that is around.

So, if universities are to continue to expand and to compete in the global higher education market, someone else has to pay.

How much cash?

The government has decided that "someone" should be graduates.

But how much extra money will "deferred variable fees" (to give them their proper name) actually deliver? And how soon will it be available?

In the short term, the answers are: not much and not soon.

This is partly because the new fee arrangements will not start before 2006 and, even then, will only affect that year's intake, not existing students.

So it will be 2009 before the full three-year cohort of undergraduates will be under the new regime.

None of them will start to pay anything back until 2010 - and then only if they have taken up jobs paying more than �15,000 a year.

Students are adamant about fees

Meanwhile, in the intervening years, the government will be paying the additional �1,000 grant to poorer students from September 2004.

And, from 2006, the government will in effect be paying the tuition fees on behalf of students.

So if Campusville University decides to charge fees of �3,000 from 2006 (remember that is a net gain over the current fees of just �1,875), it will receive that amount per student from the government.

Campusville's graduates will only start to repay that debt to the government three or more years later at the relatively low rate of 9% a year.

It will take well over a decade before the government gets its money back.

In other words, there is a substantial net loss to the taxpayer for some years to come. The technical term for this is "resource accounting and budgeting".

Benefits?

It means the cost of moving from up-front fees to deferred payment will cost the government some �600m between now and 2010.

Politically this means there will be at least two more general elections before the government will feel the benefit of a substantial inflow of graduate contributions.

What about the universities: how much will they gain?

Universities like Bristol have supported the change, believing it is the only way they will get the cash needed to maintain, and improve, the quality of education they provide.

I asked Bristol University just how much benefit it would get from the fees. The answer was surprising.

If it charges the full �3,000 for every course, they estimate their income would rise by around �6m for each undergraduate cohort.

Pain and gain

So by 2009, with all undergraduate students in the scheme, there would be a net gain of about �18m.

If, however, they have to use up to one-third of the fee income (their calculation) for student bursaries, they would be left with a net gain of �12m a year.

Bristol University's total income is a little over �200m a year. So the extra income is only equivalent to an increase of about 5 to 6%.

That seems like a lot of pain for not much gain.

This is why some universities wanted the government to allow them to charge much more than �3,000.

So far, most of the debate over fees has been whether or not the proposed fee levels are too high, as that is where the opposition is coming from.

But, especially if the government succumbs to pressure to reduce the maximum fee, there might also come a point when some universities will wonder whether it is worth the candle.

I wonder if the same is true of the government. If ministers are forced to concede some of the key principles of the scheme, will they decide to abandon the plan altogether?.