Unite members working for outsourcer Mitie at London City airport have voted for strike action.
The workers, who are employed as security guards and assistance providers to workers with mobility issues, are taking action in a dispute over pay, conditions, recognition and welfare facilities.
The workforce is seeking a significant pay increase, enhanced rates of pay for overtime and improved sick pay.
They are also demanding that Mitie recognises Unite and that adequate rest break facilities are provided.
Currently workers have a 45 minute break, but their restroom is a 15 minutes walk away from their workplace, Unite says.
Workers voted 100% in favour of industrial action on a 69% turnout.
Unite regional officer Michelle Cook accused Mitie of treating workers with contempt.
She said: "Mitie is drinking in the last chance saloon and if it wants to avoid industrial action then they need to immediately enter into meaningful negotiations and properly address the workers concerns."
