We need constructive discussion of ways to get government ÖйúAƬ policy out of its current muddle ("Fears that Willetts' hellish week may leave debate in limbo", 19 May). However, it would help if ministers posed their half-formed ideas as questions rather than as statements easily misinterpreted as new policies. This only causes alarm.

The question David Willetts, the universities and science minister, should have asked is whether the willingness of some families to pay their children's university tuition fees up front could be used to generate a larger number of places for UK students while maintaining a fair admissions system.

To that I would have responded yes - encourage those who can pay up front to do so, thus reducing the burden on the student loan book and allowing an increase in the total number of national quota places.

To avoid bias in admissions, there should be no off-quota places for individual payers: instead, the government should estimate the number of upfront payers and adjust the overall national quota to include them.

ÖйúAƬ

Initially it would be difficult to make an accurate estimate, but making estimates is part of the government's job, and it would become easier after seeing the results of the first few years.

Encouragement is already there in the new policy to charge interest on student loans, removing the perverse incentive to take out interest-free loans and invest the funds. The government should keep up this encouragement by abstaining from its previously floated idea of penalising upfront payers.

ÖйúAƬ

This policy would give an advantage to students from wealthy families because by paying up front they would avoid interest charges, but in my opinion this would be outweighed by the benefits of allowing more quota places within a fixed budget, making better use of the public funding that underwrites student loans.

Susan Cooper, Professor of experimental physics, University of Oxford