Firefighters are set to strike tonight and on New Year's Eve in the second period of strike action in two weeks.
Members of the Fire Brigades Union campaigning against government changes to their pensions will strike from 7pm to midnight tonight, 6.30pm on New Year's Eve to 12.30am on January 1 and from 6.30-8.30am on January 3.
The union fears firefighters will lose their jobs if the retirement age is raised from 55 to 60 because they may not be as fit to carry out the rigorous workload.
It has argued firefighters are likely to experience a decline in fitness in their 50s, meaning they would be unlikely to meet the fitness standard required by the service and could face dismissal.
All FBU members will stop work except those working in control centres. A ban has also been placed on voluntary overtime after a second ballot of FBU members voted nine to one for additional industrial action on top of strikes.
Matt Wrack, FBU general secretary, said: "The government must stop claiming they are negotiating when they have refused to talk for two months and insist on forcing through proposals that are unaffordable, unworkable and unfair.
"By simply conceding common sense and allowing firefighters a fair deal, the government could end this strike action today."