Hundreds of firefighters took part in a 24-hour strike in a protest over pensions.
The mass walk-out is part of a disagreement with the Government over the increase in the pension age from 55 to 60.
The Fire Brigades Union (FBU) claim the move will put jobs at risk because older members will be unable to achieve the minimum fitness levels - and they will lose their pensions.
Members are also angry the Department for Communities and Local Government has failed to publish alternative plans that the union claims it has had since March.
Today, more than 100 Leicestershire firefighters gathered at the Clock Tower during the strike to publicise the issue.
Twins Terry and Anthony Wildgoose, both 33, were among the striking firefighters.
Terry, a crew manager at western station, said: "The main points are we will have to work for longer, pay more into our pensions and get less out of it at the end.
"And if we get dismissed before 60 on fitness grounds then we get nothing.
"We need to provide for our families and these proposals will prevent us from doing that."
There have been 12 walk-outs so far in the long-running dispute, but this is the first time firefighters will have gone on strike for 24-hours.
FBU Leicester secretary Graham Vaux said the impact of the strikes might have been lost, but their argument was just as valid.
He said: "The impact of so many strikes could have been lost a little bit, but we've still got a lot of public support.
"It's not practicable to expect firefighters to maintain the same level of fitness at 60 as they did when they were in their 20s or 30s.
"The Government's own figures show that two-thirds of firefighters won't be able to achieve this - which means they lose their pensions.
"It means that female firefighters - even more than two-thirds - won't be able to achieve pensionable age."
Nicola Gore, who works at central station, said: "I'm 29, and I keep myself fit, but I'm going to have the same level of fitness at 60 that I am now.
"I pay about £220 a month into my pension and it is worrying to think that I'll miss out because of impossible targets set by the Government."
A spokesman for the fire service said there was a reduced service of seven crews operating during today's strike.
He said: "This means that a limited number of fire engines will attend a limited range of incidents and that; in the first instance, the normal initial attendance to incidents will be just one fire engine."
He added that businesses and other organisations should put additional measures in place to prevent the likelihood of fire in times of industrial action.
