Wandsworth fire station has been without one of its two fire engines for almost seven months, due to the ongoing row over pensions.
Now union representatives at the station in West Hill, Putney, are calling for the appliance to be returned, as its absence is leaving the borough constantly short of fire cover.
The station's second pump was taken by the London Fire Brigade (LFB) in August, as part of a contingency measure to cover strike action by the Fire Brigades Union (FBU) over changes to pensions.
Firefighters last walked out before Christmas, although the FBU has not officially ruled out further industrial action.
But with no plans for future strikes currently in place, Linda Smith, Wandsworth fire station's FBU representative, said the appliance should be returned.
She said: "The people of Wandsworth pay for that engine, which has been deemed essential by the London Fire Brigade.
"We accept that there is live industrial action but it is unreasonable for London Fire Brigade to keep hold of our fire engine when there are currently no strike dates in place.
"Our cover has been halved for almost seven months and there have been occasions where we have thought if we had both our fire engines we may have got to an incident quicker.”
Ms Smith said the reduction of appliances across London now meant Wandsworth fire station was empty for large periods of time if the one remaining pump was elsewhere.
Usually, when a station is out on a job, it is common practice for a nearby station to “backfill” by supplying an extra pump in case of another emergency.
But that is not happening at Wandsworth, Ms Smith said.
She said: “If our fire engine is detained at an incident, they should send a fire engine to our station to cover. But for quite a long time there is no fire engine going to Wandsworth when we’re out.
“It’s so frustrating knowing, our fire engine has been sitting idle for months, doing nothing.”
For the past six months, Wandsworth has relied on fire engines from Tooting, Battersea, Fulham and Richmond to provide an obligatory second pump for fires in the borough, Ms Smith said.
And she cited a call on February 18 in Portinscale Road, Putney, when crews from Tooting and Fulham saved a woman and a three month old baby from a fire in a masionette.
The fire was just a few minutes from Wandsworth fire station, but the station's one remaining fire engine was elsewhere.
Ms Smith said: "If there had been a fire engine at Wandsworth, it could have got there in two minutes, instead of the eight that it took."
She added: "There's been no consultation on this, and residents have not been given a council tax reduction.
"Our leadership are still in the negotiations with the Government to try and get a resolution, but everything we're hearing is it's likely to be protracted.
"Our pension scheme is due to come in in 2015, and we will be in dispute with the Government until it is resolved.
"During this time, the people that are suffering most are the people of Wandsworth and Putney."
The LFB temporarily removed 27 fire engines from London fire stations as a contingency when the FBU first balloted members over strike action in July and August last year.
Some have since been returned to fire stations.
A LFB spokeswoman said the brigade was legally bound to hold on to some appliances until the FBU called off any potential strike action in the future.
She said: "Because the union has not called off its strike action we cannot return the pumps.
"They will be returned but only when the FBU say they are not going to strike again."