Local government staff have voted for a programme of strike action over a 2.45% pay offer.
Members of Unison in England, Wales and Northern Ireland have voted by 55% to 45% in favour of the strike. The union's negotiating team will now meet to decide what action to recommend to the national strike committee on Friday.
The joint trade unions' pay claim was for 6% or 50p an hour, whichever was greater.
Nearly 600,000 Unison members were balloted on industrial action including social workers, refuse workers, teaching assistants, cooks and cleaners. Almost 250,000 of these currently earn less than £6.50 an hour.
Dave Prentis, general secretary of Unison, said: "This is a solid vote for action and a clear message to the local government employers that our members are willing to fight for a decent pay rise. Most of them are low-paid workers, who are hit hardest by food and fuel price hikes and they see the unfairness of boardroom bonanzas and big city bonuses."
However, David Frost, director general of the British Chambers of Commerce, said strike action would be detrimental. "Striking in the current economic climate will only lead to worsening inflationary pressures. Furthermore, the public finances are not strong enough to dish out any extra pay without further taxation to fund it. Far too many days are lost to strikes already, which is having a damaging effect on both business and the image of UK plc. The government needs to stand firm and resist the pressure unions are trying to impose."