The biggest argument against tuition fees is that they will discourage poor people from going to university. I can't prove this won't happen, but it really has to be a psychological argument. Whether you are poor or rich, if you will get cheap loans to go to university, and have the capacity to do so, it is an insanely good deal, at £7000 a year or at £3000 a year. On average, the increase in your income will pay for itself many times over. So the story has to be: people will be scared off by the sheer amount of debt, and the uncertainty involved. That could be true. People are not perfectly rational calculators, and large debts can be frightening (except to all those geniuses in the City). However, it seems less likely to be a permanent effect. When people get used to the idea of large student loans, and when they see others using them, they will no longer seem so frightening. In particular, the US, which funded university via loans, had a high proportion of people going to college long before most of Europe did. That suggests that loans do not have to scare people off. (My friend Luke made the point that US education was boosted by the free university places given to WWII and Vietnam vets. It is an interesting story. The original GI bill put 8 million people through college. But it seems more likely to provide a kickstart than to have sustained high US college enrolment over the whole postwar period.)
What if you are poor but want to do something idealistic rather than making pots of extra money from your university education? You might then be put off, and either skip university or choose a money-making career. This would be unfair to you, and would also deprive the UK of the benefits of people who do idealistic but low-paid jobs like teaching or social work.
Well, it has to be a very idealistic job for it still not to benefit you to go to university. I am an academic, which is quite idealistic... oh go on, it is. But I will still earn much, much more over my lifetime than if I hadn't gone to university. (Back of the envelope calculation: half a million more.) That holds also for Luke, who is a teacher, or Kemal, who works in a development organization. If you are planning to be Mother Teresa, then yes, you could be put off by debt. But most people do not volunteer all their lives.
There are too few people from poor backgrounds going to university. But what causes this? My hunch is that it is that many people know they would not get accepted at a university, and/or would not be able to benefit from it. For example, you will not get much from university if you cannot write an undergraduate essay. Unfortunately, many 18-year-olds can't. Perhaps some of this is down to natural inequalities in intelligence. But surely a lot of it is down to problems in the education system before university. If you have not been well taught at school, then you won't get a university place. In fact, even in the golden days of free education, the educational inequalities existed (see Figure 3 on page 6). And a study of the original introduction of tuition fees suggests: "much of the impact from social class on university attendance actually occurs well before entry into HE."
If so, then the best way to get equal access to university is to improve the quality of pre-university education, especially for the poorest. That seems to be the idea behind the pupil premium. The Lib Dems will probably get slaughtered over the tuition fees increase. That's a shame, because Nick Clegg is trying to do the right thing.