Labour is facing the prospect of defeat in a Welsh assembly vote on student top-up fees next week.
Students could have to pay for their own education
It is the assembly government's first big test since Labour lost its majority when Peter Law left the party to stand against it in the general election.
The Conservatives have proposed a motion on top-up fees on Tuesday which has united opposition support.
Independent AM and MP Mr Law, whose vote is now crucial, said he wanted a free education system.
"As a socialist, I believe in a free education system and I have told them in the assembly a number of times," he said.
"I'm not going to say which way I'm going to vote at the moment, because I'll be talking to students as well, but I expect to be there to exercise a vote for the people of Blaenau Gwent.
"What I will do is what I think is appropriate as far as the students of Wales are concerned."
The debate has also proved controversial because it will come two days before the publication of an independent report.
Its author Professor Teresa Rees has written to AMs pleading with them not to debate the issue before her research is published on Thursday.
She told BBC Wales' Dragon's Eye that discussing it before then was "bonkers".
"My concern is they are not even looking at the evidence before debating on this very important issue," she told Dragon's Eye.
Peter Law is no longer a Labour AM
"To then have a debate on it two days before the report comes out is bonkers, frankly.
"I would really like to see this motion withdrawn and I would like to see the proper procedure followed.
"Why have a debate before the report comes out? What possible reason could there possibly be unless it is mischief-making?"
Conservative AM Jonathan Morgan said it was "regrettable and unwise" for Professor Rees to enter the debate.
"The fact of the matter is there should be nothing which should prevent the Welsh assembly from debating a particular view and that is what we are doing next week," he said.
"It is not playing politics, it is allowing the assembly to debate an important issue."
Education minister Jane Davidson said she was "dismayed" to hear of the intention to hold the debate two days before the report.
"I have always advocated that the views of the independent group should be listened to before decisions are made for our students and institutions," she said.
"I believe in informed decisions not hot-headed ones."
Plaid Cymru AM Janet Ryder said her party believed fees were not the way to pay for higher education.
Lembit Ípik, leader of the Welsh Liberal Democrats, said it would be remiss of his party not to make its opposition to student fees clear.