By James Hardy
Political correspondent, BBC News
Public sector workers are getting increasingly angry about pay
Unions have voted for coordinated industrial action across the public sector in protest the government's below-inflation pay offer.
But committing the TUC to organising strikes involving upwards of two million workers and half a dozen unions is one thing.
Making it happen is quite another.
Each union is at a different stage in consultations with its members and there are doubts about how widespread is the appetite for action.
The key players are the PCS civil service union and Unison, the dominant union in local government.
Workers in both have already rejected a three-year pay deal worth just under 2.5% and now look certain to be balloted on industrial action.
A strike vote by those two unions alone would potentially see walkouts by up to a million civil servants and local government workers.
Due to the complexities of balloting, coordinated action is unlikely before November at the earliest.
Even then there's no guarantee such action would get solid support - and Unison in particular is wary of a patchy response by its members.
The GMB and Unite are still consulting their combined 330,000 local government members and both report anger at the pay offer.
But that doesn't mean they'll necessarily want to go on strike.
Postal workers and prison officers are still in dispute - but the former are already involved in stoppages and, despite walkouts last month, the latter are banned by law from striking.
The teaching unions, in the middle of a two-year deal, could become part of the equation if their independent pay review body fails this autumn to recommend an acceptable deal for next year.
So, while traditional union solidarity dictates full support for the PCS call for coordinated action, in practice an "autumn of discontent" is going to be hard to deliver.
The bigger unions have wider issues to consider. Few of them are seriously interested in going head-to-head with Gordon Brown so early in his premiership.
While there is genuine fury at the public sector pay deal that he engineered as chancellor - and his decision to stage it - some more moderate union leaders hope that a lesson might have been learned at Downing Street.
But there is a fear that Mr Brown is looking for his own "Clause 4 moment" to match Tony Blair's decision to rewrite the Labour constitution at the start of his leadership - a decision which stamped his leadership on the party.
If so, the flashpoint will come over his move to limit union influence at the Labour conference.
Ministers attending the TUC are working hard to strike a deal and may yet succeed. But if Mr Brown really is looking for a fight, he might well get one.