Firefighters are to be balloted over the summer on possible strike action over proposed changes to pensions, the Fire Brigades Union said.
The FBU denounced the proposed changes as "unworkable" and warned that they could lead to thousands of firefighters facing the sack as they get older.
The union said that the decision to hold a strike vote after almost two years of negotiations was prompted when the Government set a deadline of July 12 for firefighters to accept proposals or face the imposition of the changes.
The ballot will take place between July 18 and August 29 and dates for any walkouts will be announced later if there is a vote backing industrial action.
The FBU has been locked in negotiations over pension changes which the union argues would impose a sharp increase in members' contributions and put firefighters at greater risk of dismissal without access to a proper pension if they cannot maintain fitness standards as they approach the retirement age of 60.
The union claims that the current proposals would see firefighters who retire or are forced out of work at 55 losing around 50% of their pensions.
FBU general secretary Matt Wrack said: "Expecting large numbers of 60-year-olds to fight fires and rescue families is dangerous to the public and to firefighters.
"The Government is simply ignoring the evidence about the physical demands of firefighting and has been unable to answer our concerns during two years of negotiations.
"None of us want a strike, but we cannot compromise on public and firefighter safety. We hope common sense prevails, and the Government returns to the negotiating table."