The landmark judgment is certain to bolster Sam Galbraith's resolve to scrap the Scottish Joint Negotiating Committee and introduce greater flexibility into teachers' contracts.
It is now argued that a locally managed education service dictated by national negotiations on pay and conditions is no longer an option as an unintended consequence of the equal pay claim by members of the Head Teachers' Association in Scotland, who are demanding wage parity with secondary colleagues.
In a preliminary judgment that is certain to be contested by councils all the way to Europe if necessary, the tribunal found that a South Ayrshire primary head could claim parity with a secondary head in Highland. The tribunal's view is that education is a unified national service, and local authorities have little freedom to vary contracts.
Linda Marsh, who advises councils on equal pay, said: "It's a very significant legal point about the status of local authorities which has only been made possible because of the peculiarities of the SJNC.
"The SJNC agreement has now provided a vehicle for 'industry-wide' comparisons across authorities. We have feared this might happen for seven or eight years. It was perhaps inevitable."
Ronnie Smith, general secretary of the Educational Institute of Scotland, disputes this interpretation. "I do not think there are any significant consequences that flow from a fairly technical argument. A somewhat exaggerated construction is being put on it," Mr Smith said.
The authorities defended their corner fiercely at the tribunal because of the considerable financial implications and the effects on other council workers. Groups such as social workers could use the ruling to claim parity with colleagues in other authorities on better pay and conditions.
Two options face Mr Galbraith if the tribunal's finding is not overturned, council advisers say. The first is to opt entirely for local bargaining to rule out any new reverses. The other is to centralise even more.
Some union and local authority leaders are talking in private about the end of council-led education services with the advent of the Scottish Parliament and increasing central control of budgets and policy. This latest development could push them further towards radical reform.
Employment of teachers could be removed from council control, although that could have far-reaching consequences for local democracy. It would be possible for Mr Galbraith to use the tribunal's ruling as an excuse to bring them under his control, making them civil servants as in 12 out of the 15 European Union countries.
The McCrone inquiry into future structures for teacher pay and conditions might even examine such an option. It has already agreed to commission research into European alternatives.
But teachers wary of any changes to conditions once his report is in the minister's hands next spring can draw comfort from their existing contracts, which contain all the terms and conditions set by the SJNC and cannot be altered unilaterally. Ministers and councils realise that change must be voluntary.
A two-tier structure within the profession is likely following the McCrone report, in line with the original management proposals. Teachers may be free to opt in or out of changes.