Firefighters will strike on Monday in protest against plans for a new shift system, the Fire Brigades Union has said.
The eight-hour strike will go ahead after the collapse of 11th hour talks with the capital's brigade.
The brigade wants to change the current 15-hour night shift and nine-hour day shift to provide a longer day shift.
Fire Brigades Union (FBU) regional official Paul Embery said: "We are clearly extremely disappointed that the London Fire Brigade (LFB) representatives brought absolutely nothing new to the meeting today and all they did was reiterate their position held for several weeks.
"They point blank refused to lift the threat to sack 5,500 firefighters and consequently the strike action planned for tomorrow and November 5 and 6 remains on."
The eight hour strike will run from 10am to 6pm across London involving 5,500 firefighters and 111 fire stations.
Mr Embery said the FBU had called a further meeting for Tuesday but the LFB were yet to commit to that.
London Fire Brigade assistant commissioner David Brown said they were "extremely disappointed" at the breakdown of the talks.
"We think it's reckless and completely irresponsible. There is no need to strike, we've been talking all day today about a variety of options. We invited the FBU for independent arbitration on two separate dates and they refused."
Mr Brown said of the strike action: "It is clearly a challenge for us, but the service provided is an adequate service. It is there for normal business."