Leader: Sour notes lost in political noise

Party conference season is no time to expect straight answers to awkward questions about any policy, let alone one as sensitive as the introduction of top-up fees. There is too much at stake for the seaside knockabout to give way to reason. Although it looked like an opportune moment for the Higher Education Policy Institute to publish its comparison of the likely costs of the various proposals, there was always a danger that an important analysis would be lost in the political noise.

And so it proved. Each party has seized on the predicted shortfall in university funding under its rivals' programmes without addressing the doubts about its own. The Conservatives dismissed Hepi's calculations as "peculiarly half-baked" but did not rebut the claim that their proposals would see hundreds of thousands of qualified students denied higher education places; the Liberal Democrats highlighted the estimated £1.6 billion "black hole" in the government's plans while ignoring the £2.6 billion tax liability attributed to their alternative; and education secretary Charles Clarke declared the report "good news" for the advocates of fees while skirting round its long-term implications.

The Hepi report makes some questionable assumptions about future growth in the number of successful A-level candidates (though not about grade inflation, as the Tories claimed). But there is no denying the impact of demography when those who will be 18 in 2010 are already in secondary schools. Even assuming current participation rates, they will produce 150,000 additional candidates for higher education who seem not to feature in any of the parties' calculations. Ministers are well aware of their existence but turn a blind eye to the implications for their 50 per cent participation target and the cost of fee subsidies.

Meanwhile, both the Lib Dems and the Conservatives imagine that they can fund higher education adequately from general taxation. The Lib Dems would make some savings by forcing more students to live at home and steering others onto two-year courses. But they would have to pour more than half of their proposed 10p tax increase on salaries above £100,000 into higher education for the books to balance. However highly they value universities, this seems unlikely, given their other spending commitments.

The Tories have no such problems because they are promising to hold down taxation and public spending, reducing student numbers to unspecified levels. But that does not mean that their "No fees; no small print" campaign adds up either financially or politically. The number of qualified candidates squeezed out by the policy might not reach the 450,000 predicted by Hepi, but it will surely be far more than a party with hopes of election success could contemplate. The Tories may glory in the popularity of their anti-university pledges next week but, like their rivals, they have some thinking to do when the partying is over and they have to produce a system that works.