In many ways the National Association of Head Teachers withdrawal from the school workforce agreement is largely symbolic.
It does not mean heads can now opt out of implementing the deal, no matter how short of cash they are. The agreement, signed with Government, employers and other school staff unions, is binding on all schools regardless of which union their heads belong to.
It should also make little difference to NAHT involvement in local talks: National Union of Teachers' representatives have been involved in such discussions, despite never signing up to the deal.
The decision to withdraw is likely to mean the NAHT is excluded from national talks with the Government and employers on many issues beyond workforce reform. It could mean the association being thrown out of the broad social partnership that has developed between Government and unions over the past two years.
But withdrawal also represents a major blow for legitimacy of that partnership which will now have to operate without the consent of both the largest classroom teacher and headteacher unions.
And that is the thinking of NAHT members who voted to pull out this week.
They wanted to make a major statement highlighting the plight of colleagues who say they do not have enough funding to implement the deal without compromising standards.
Funding was an issue for the association before the ink had even dried on the agreement. In the week the deal was signed in January 2003, David Hart, general secretary, said the NAHT would pull out if heads did not have the money to implement it.
It was a threat he was to repeat many times as that year's school funding problems emerged, and the issue has never been resolved.
This week's meeting was at least the fifth time the association has formally considered withdrawal over funding.
The issue came to a head at last May's annual conference in Cardiff when delegates said involvement should be dependent on the Government announcing "clear, adequate and direct funding" by the end of 2004.
In November the union's executive decided that had happened and voted by 29 votes to 13 to stay on board. But large numbers of primary heads remained concerned they would not have enough money to implement the 10 per cent planning, preparation and assessment time guaranteed to teachers from September, without compromising standards.
Growing grassroots dissent persuaded the executive to hold this week's extraordinary general meeting to try to secure backing for its decision.
Mr Hart believes the failure to do that will have consequences that stretch beyond immediate withdrawal from the national Workforce Agreement Monitoring Group (WAMG), made up of other unions, the Government and employers. "WAMG is now being used by the department for much more extensive consultation than was originally imagined," he said. "It was recently asked to comment on extended schools."
He is also concerned that the association's withdrawal from WAMG will mean exclusion from the parallel Rewards and Incentive Group, although the two are theoretically separate. The rewards group discusses teacher pay and conditions with Government.
"The implications are that we may also not be able to represent our members in other forums at the Department for Education and Skills such as the school funding group," he said. "This could leave our members totally disenfranchised."