Higher education minister Alan Johnson

The government's policy on tuition fees will not change, the higher education minister has warned.

Addressing the Universities UK annual conference of vice chancellors, Alan Johnson also said that there was not any cash left to fund bigger grants for poorer students.

However, he pledged to "put a wet towel around my head" and look at other ways of helping them.

"We will look very hard at how we can find the money to bridge the gap," he said.

"That's where our efforts ought to be - I think we've gone as far as we can on the maintenance grant.

"I want to look really hard at this, put a wet towel around my head and see how we can resolve it."

The new measures were fair and would be brought in "touch wood," he added.

His comments came as opposition to top-up fees became more vocal, both among backbench MPs and in the trade union movement.

A survey published on Tuesday revealed that 80 per cent of those surveyed were against the government's policy.

And the TUC unanimously passed a motion at its annual conference condemning the plans for variable fees of up to £3,000 per year.

It has been suggested that the government would attempt to buy off criticism through forcing universities to make more money available for bursaries from their extra cash.

But Johnson denied this was an option he is considering ahead of the publication of new higher education legislation expected in November.

"We haven't got any more money to make maintenance grants higher but at some future time, of course we will continue to look at maintenance grants," he admitted.

The minister was responding to calls from Professor Ivor Crewe, president of UUK, who called for greater action from the Department for Education and Skills to help the poorest undergraduates.

"The government should rationalise what has been called the dog's breakfast of existing special grants in order to increase the maintenance grant and to widen its eligibility," he argued.

"And it should reform the current loan system so that students are less dependent on expensive credit card and bank debt."

National Union of Students president Mandy Telford claimed that Johnson's comments showed "contempt" for public opinion on the issue.

"Coming a day after the TUC unanimously condemned top-up fees and a poll showed that 80 per cent of the general public oppose them we are amazed the minister has chosen to show such contempt for the views of the majority," she said.

"To talk about higher education as a market and students being forced to pay what a market dictates is an affront to those students who are already struggling by on a daily basis.

"To not understand why a working class 18-year-old would be put off racking up a debt of £20,000 plus further demonstrates just how wrong the government is on this issue."