The country's biggest public sector union yesterday decided to coordinate pay campaigns in the NHS and local government, raising the prospect of a strike by millions of workers in the autumn.
Unison said its members working in the health service and for councils were growing increasingly angry at separate, deadlocked pay disputes.
Both sets of workers should have received a pay rise in April but no agreement has been reached.
Unison's annual conference in Brighton decided yesterday to coordinate any strike action between the NHS and local government, as well as linking up with other trade unions who are also in dispute over pay.
Unison said it wanted to team up with other unions to create "maximum impact" in the event of an industrial action campaign.
Moving an emergency motion at the conference yesterday, Jane Carolan, a member of Unison's executive said: "I'm sure Cherie Blair doesn't have to wait for the Co-op divvy cheque to come in before buying the kids' school clothes, or decide whether to pay the electricity or the gas bill.
"Many of our members do. We are trying to provide 21st century public services, and we deserve 21st century pay."
Unison's general secretary Dave Prentis said he wanted to give a strong message to Gordon Brown, who takes over as Prime Minister next week, that the union was prepared to take strike action.
"Public sector workers in the police, councils and health services are sick of being treated like second-class citizens."
Mr Prentis said a 2% pay offer made to council workers was a "pittance" and was well below rising living costs.
"It is effectively a pay cut and kicks them in the teeth."
Health workers were recommended a 2.5% pay rise by an independent body, but the Government decided it should be paid in two stages, reducing the award to 1.9%.
Unison represents 465,000 health workers and 850,000 local council workers.