Michael Howard has challenged the prime minister on the issue of student top-up fees.

Mocking Tony Blair's recent "big conversation", the Tory leader asked how many members of the public had backed the government's controversial plan to reform student finance.

"If in the course of the 'big conversation' the majority of people say they don't want top up fees, will he listen to them?" Howard asked.

To loud jeers from Tory MPs, Blair sidestepped the question, claiming Conservative plans would mean fewer working class young people going into higher education.

But Howard said Blair was in no position to lecture him on access to higher education.

"This grammar school boy is not going to take any lessons from this public schoolboy [Blair] on the importance of children from less privileged backgrounds gaining access to university," said the Conservative leader.

And he warned the prime minister that he had a duty to answer questions on the government's policy.

"It is my job to ask the questions on behalf of the British people and it his job to answer them on behalf of the government," he argued.

He went on to slam the prime minister's failure to listen to the concerns of voters.

"It really doesn't bode well for the 'big conversation' that in this quite small conversation the prime minister isn't prepared to answer the questions," Howard said.

"If the prime minister isn't prepared to listen to the answers he gets on top-up fees, on foundation hospitals or on the European constitution what on earth is the point of this ludicrous exercise?" he asked.

"Doesn't the prime minister realise quite how ridiculous he's beginning to look. If he won't listen to the people why on earth should anyone listen to him?"

Blair, however, reminded MPs of the message voters sent out after 18 years of Tory rule.

"Let me tell him what they told us. They said 'we wanted an end to boom and bust economics', and we provided it," said the prime minister.

"They said they wanted they wanted an end to mass unemployment, and we provided it. We're talking about the future, things for which we've got answers and he's got none."

Charles Kennedy also tackled the prime minister on the issue of university funding.

The Liberal Democrat leader demanded to know whether the vote, expected in late January, would decide the fate of the government.

"What he's saying is he's prepared to force his own MPs through the lobby, on a confidence vote, to introduce a policy in direct contravention of what they said in their own manifesto," said Kennedy.

"Is that the action of a prime minister who's a strong leader or an increasingly desperate one?"

But the prime minister went on the attack, claiming Kennedy's own solutions were unworkable and uncosted.

"His idea is to raise the top rate of tax. That is completely unfair," said Blair.

"It is wholly dishonest to pretend that you are going to get £15 billion from the top rate of tax. Until he's got a serious policy, he won't have a serious party."