A Labour backbencher has delivered a scathing attack on the prime minister over top-up fees.

Barnsley Central MP Eric Illsley told Tony Blair to change his position on university funding or resign.

The MP's comments on Monday were provoked by the prime minister's claim that Labour MPs would be betraying the country by voting down the Higher Education Bill that will introduce top-up fees.

Illsley described Blair's comments at the weekend as "crap" and the policy as elitist.

"If he is going to carry on like this, he ought to stand aside and let somebody else have a go," he told the Yorkshire Post.

"Who the hell is he to tell me I am betraying the country? It's crap."

Illsley turned Blair's comments back on him arguing the prime minister had "betrayed the country'' by going back on the party's 2001 manifesto pledge not to introduce fees.

The MP, who is one of around 100 Labour backbenchers that were unconvinced by the government's concessions, said he was standing up for "my class - the people I represent".

Labour has prided itself on discipline and avoiding damaging rows so there will be embarrassment that one of its MPs has decided to join the ranks of Clare Short and Robin Cook by delivering a direct attack on the prime minister.

But Blair signalled he will mount a robust defence this week of his plans to reform student finance.

The prime minister will begin a fresh push to defend the plans for variable tuition fees of up to £3,000 per year when he takes part in a radio phone-in on Tuesday.

He will then deliver a high profile defence of the controversial proposals in a speech the following day.

On Wednesday the education secretary Charles Clarke is also set to face a rough ride when he addresses the parliamentary Labour Party.

Over 100 Labour MPs have vowed to press ahead in opposing the plans despite 11th hour concessions from ministers.

By Thursday the attention will shift back to the prime minister who will appear before the media for his monthly press conference.

The row over university top-up fees continued over the weekend, with claims that both Labour and the Conservatives are split on the issue.

As Blair and Clarke continued their campaign to win over sceptical Labour backbenchers, the Liberal Democrats predicted significant numbers of Conservative MPs were set to back the government.

A knife-edge vote on the issue is expected in the Commons later this month, and despite last week's concessions it remains unclear whether ministers will be able to gain parliamentary approval for their Higher Education Bill.

But speaking on Sunday Blair said he was not prepared to "contemplate defeat" in his battle to ensure the policy reaches the statute book.

"I have not contemplated defeat and don't intend to. We need to win this," he told the BBC's Breakfast with Frost programme.

Reports suggest that more than 100 rebels could vote down the plans, prompting a possible vote of confidence in the government.

"It is extremely important to the whole authority of the government that we do win it," Blair accepted. "But more important, it is important for the country that we win it."

The plans will see the introduction of variable fees for university courses, along with the extension of maintenance grants for the poorest students and the abolition of upfront fee payments.

"It is a good deal for universities, who are going to get a substantial extra increase in funding," said Blair.

"It is a good deal for poorer students, who are going to get £3,000 worth of help every year through university.

"And it is a good deal for middle-class students and parents because they will not pay anything up front. They will repay something when the student graduates on far more generous terms than today."

While the prime minister pledged to "be out there fighting for this all the way in the coming weeks", the Conservatives have set out their continued opposition to the policy.

Leader Michael Howard warned it could leave universities worse of, and rejected claims his party had taken an opportunist position to embarrass the government.

"You've got to apply your principles in accordance with what is going to achieve the best result," he told Sky News.

However Howard also accepted that his party had not set out any proposals of its own to improve higher education funding.

"We recognise more will need to be done and we are working on seeing how we can do more to meet the financial problems which universities face," he said.

That admission prompted the Liberal Democrats to accuse the Conservatives of "just playing political games" with the issue.

"The Tories are talking themselves up as a stronger opposition under Michael Howard but their opposition to top-up and tuition fees is opportunistic and shaky," leader Charles Kennedy told GMTV's Sunday Programme.

"Once again Michael Howard has demonstrated he has no coherent alternative while many in his party actually agree with the government."

Meanwhile, Lib Dem education spokesman David Rendel predicted that 14 Conservative MPs would defy their party whip and back the government.

"Some of them may merely abstain rather than voting positively with the government but something in the order of 14 is the likely figure at present," he told BBC Radio 4's World This Weekend programme.

Continuing the debate, education secretary Charles Clarke said the Conservative position on higher education was "untenable and dishonest".

"It is clear from his interview today that Michael Howard and his party's approach does not stand up to the slightest scrutiny," he said.

"He should have taken the opportunity to ditch Ian Duncan Smith's ridiculous policy which many of his party, universities and serious commentators disagree with.

"When they vote it will not be a vote of principle but pure opportunism."

But many Labour MPs appear determined to join the Conservatives in the division lobbies.

One leading rebel, former chief whip Nick Brown, insisted he would not back the proposals

"I want to defeat the proposition but I think we will then need to return to it because there is a need to get more money into higher education," he told Sky News.

Number 10 has signalled that Blair stands ready to meet small groups of Labour MPs in a bid to head-off his first Commons defeat on a major policy issue.