The dispute could bring a large chunk of the network to a halt as tube drivers say they will refuse to work if safety-critical maintenance staff are not available.
The 24-hour stoppage will begin at 6am on March 12, covering workers on the District, Circle, Metropolitan, Hammersmith & City and East London lines.
Some 480 members of the Rail, Maritime and Transport union backed industrial action by a five-to-one margin in protest at the dismissal of five staff by Metronet, the private engineering company responsible for maintaining two-thirds of the network.
The employees were sacked following the discovery of 111 beer and cider cans, plus an empty bottle of brandy, in a cabin at Farringdon station.
Metronet claims the workers had breached its zero-tolerance policy over alcohol at work. It said they used the cabin regularly and must have been aware of the presence of the stash.
But the RMT has accused Metronet of victimisation, insisting there was nothing to link the individuals to the alcohol. It says the staff were picked out because they were pursuing a grievance against a manager.
Bobby Law, the RMT's regional organiser, said that in 20 years of union experience, he had "never witnessed an injustice on this scale".
"They did use the cabin, but so did everybody else," said Mr Law.
· Safety inspectors have voted for industrial action in a pay dispute with the Health and Safety Executive. The row includes staff who monitor the railways, nuclear power stations and construction sites. Prospect, their union, has objected to a pay offer of 3.7% but has agreed to talks at the conciliation service Acas.
