The country's biggest union today raised the threat of a general public services strike against the government unless ministers and other local employers continue to offer big pay rises to council and hospital staff.
The move could paralyse swaths of the public sector and place in serious jeopardy the government's plans to improve services by introducing more flexible working practices and pay scales.
Leaders of the 1.3m-strong public service giant, Unison, are due to debate the proposals at their annual conference in Brighton next week, but the move already has the backing of the union's leadership, making success likely.
The motion calls for a more "coherent" approach to industrial action - a clear indication that if workers in local government and health both reject a pay claim, then they could launch coordinated strike action.
A spokeswoman for the union said: "The underlying strategy is that if you're getting a situation where you are going to have the possibility of action over a particular pay claim, and this was a problem across the sectors, then the motion is saying that consistency would strengthen our hand."
The union's leadership believes the current fast rises in public pay - which continue to outstrip increases in the private sector - could be jeopardised by pressure from the government, private sector and the media for restraint.
They argue that "fair and improved pay" is in fact a crucial factor in improving the quality of public services.
In the wake of last year's local government strike, sections of Unison's membership believe industrial action is becoming an increasingly effective way to boost terms and conditions. The national stoppage organised by the union wrung an improved offer from council employers.
The law currently prohibits people from becoming involved in industrial action that does not directly affect them, but Unison's strategy of coordinating pay claims and industrial action would allow the union to circumvent those regulations.
The union's threat will carry little immediate weight because council staff have just entered the second year of a two-year pay agreement and NHS workers are just entering a three-year deal. Unison's spokeswoman confirmed that her message was not one of "general strike now".
But it nonetheless indicates a hardening of the usually supportive union's attitude towards the government in the wake of the ongoing firefighters' dispute, calls from the chancellor to examine regional public pay deals and rows over policies such as foundation hospitals.
A hawkish motion from Unison activists in Lancashire says: "Where unions and their members make a consistent and determined stand, they can obtain substantial pay rises and improvements to their working conditions without giving up job numbers of sacrificing other conditions of service."
