London faces travel disruption as tube workers plan to strike for 24 hours over a colleague who was sacked after allegedly failing an alcohol breath test.
The Rail, Maritime and Transport Workers (RMT) union said 57% of the 521 members who took part in the ballot voted for the action and 42% were against the move.
The walkout, which has been called across all London Underground lines, could take part as early as 17 February.
"Our members have voted for industrial action and the union will now consult extensively with our representatives before deciding on our next moves in this dispute," said Mike Cash, the union's general secretary.
"The union remains available for talks, at Acas if necessary, and as we have already stated we are ready to abide by any decision made at an Employment Tribunal and cannot understand London Underground's reluctance to agree to that course of action."
London commuters recently endured travel chaos from recent bus strikes over pay.
Another walkout from members of Unite is planned for 13 February and Transport for London (TfL) has advised people to seek alternative methods of transport.
"I am very sorry that the leadership of Unite again seems intent on disrupting the journeys of bus passengers and losing bus drivers even more pay," said Mike Weston, TfL's director of buses.
"We urge Unite to call off the strikes and instead meet with the bus companies individually to resolve their differences."
TfL had not responded to a request for comment on the tube strike announcement at the time of publication.