The National Union of Students has been accused of barring attempts by a local student union to disaffiliate, in an attempt to hold on to hefty membership fees.
Students at Southampton University who voted to disaffiliate from the NUS had their decision overturned by their former union president, who now sits on the NUS executive. Southampton's student union council is taking legal advice on whether it still has to pay the NUS its annual membership fee of Pounds 64,000.
The last-minute decision to invalidate the vote was made by out-going president, Alex Bols, who is now a member of the NUS executive committee.
His explanation for his decision has baffled Southampton's student leaders. He said it was on the grounds that the representative of students attending Southampton's New College missed the disaffiliation vote because it took place three days outside its term-time. But Southampton union leaders say the ballot was won without New College's vote.
Under the terms of the Education Act 1994, membership to an external body has to be actively renewed by a positive vote, rather than just continuing with the status quo.
Graham Poole, Southampton's newly elected president, said he did not want to blame Mr Bols for the situation, but added: "The NUS has taken the invalidation of the council decision as a vote to stay. No positive decision to reaffiliate has been taken, so Southampton are out of the NUS."
An NUS spokesperson said: "We have queried the validity of the decision and asked Southampton to hold a referendum rather than let a handful of activists decide for the rest of the students."
The issue has been complicated further by NUS claims that Southampton missed a July 1 deadline for student unions to inform them of plans to continue or discontinue membership.
Mr Poole maintains a letter outlining Southampton's intentions was sent to the NUS before the cut-off date. But the NUS claims it has no record of it.
A referendum is scheduled for the start of the next academic year, but Mr Poole fears this will also present problems.
"The NUS wants us to ask the students 'Do we stay?' while the union wants to ask 'Do we go back?'" he said.
The Pounds 64,000 question still hangs heavy over Southampton's future and Mr Poole is due to meet with NUS president Andrew Pakes to clarify the situation.
"If the NUS sticks to its assertion that no letter was received, it could be tricky for us," Mr Poole said.
Stephen Day, education and welfare officer at Southampton's student union, who supported disaffiliation, feels membership costs are too high: "We are not happy with the service we get. We could spend the money better ourselves. The NUS has failed us on the two most important issues: tuition fees and the abolition of grants."
The NUS receives Pounds 3.2 million per year from affiliation fees. The affiliation cost is based on the student population and the block grant the union receives from the university.
Owen James, NUS national secretary, admitted this could lead to universities with similar sized student bodies but unequal block grants paying different sums.