The Educational Institute of Scotland has seized on official figures showing huge variations in college costs to renew its long-standing assault on the way colleges are governed.
The data reveals a considerable range in college reserves, from pound;41 million in Aberdeen to minus pound;10m in West Lothian (2007-08). It also points to disparities in senior management salaries, from pound;3m in Motherwell to pound;276,000 at Kilmarnock (2008-09).
The figures in the financial reports for each college are available on the Scottish Funding Council's website, but were obtained by the EIS through a Freedom of Information request.
David Belsey, the union's further and higher education officer, argues that the major differences in the state of college finances are due to their governance structure.
"Each college's board of management has excessive freedom with which to make financial decisions, and it has no requirement to justify its decisions," he said. "The current governance system for FE colleges creates an island mentality within many colleges that leads to a fragmented and inconsistent FE system."
Mr Belsey also points to the great variation in expenses paid out to members of college boards as further evidence to back the union's demand for greater "democratisation" of the boards. Lews Castle in Stornoway paid out the most in 2008-09, at pound;6,000, while Cumbernauld and Stevenson in Edinburgh paid nothing.
And expenses for senior management also vary, from pound;37,000 in Motherwell to pound;399 in Coatbridge.
Mr Belsey said: "The current governance structure within Scotland's FE colleges allows management teams to develop at the behest of the college board of management. Some colleges have disproportionately large management teams, and some colleges spend four times more on senior management than other colleges."
Although the figures do not reveal details of the salaries paid to individual members of senior management, the EIS says it believes their pay has risen in recent years at a higher rate than that of the teaching staff.
But Scotland's Colleges, representing principals and board chairs, and the Scottish Funding Council (SFC) argue that the variations in the figures simply reflect variations in college size and location.
An SFC spokesperson said: "All colleges in Scotland are audited by external auditors appointed by Audit Scotland, and their finances are monitored closely by the Scottish Funding Council. Any issues with financial management would have been highlighted in their reports."