London commuters face disruption ahead of the Christmas rush as tube drivers on the Northern Line plan to stage a 24-hour strike in December.
The Rail, Maritime and Transport Workers (RMT) said that its members will walkout from 04:44 hours on Monday 1 December until 04:43 hours on Tuesday 2 December.
The union said that the action is in response to the "victimisation" of one of its members.
The worker is alleged to have been drinking on the job but the union argued the move is a "blatant and clear cut case of victimisation".
The strike ballot, which opened on 30 October, closed on 18 November.
"RMT has been pointing out for some time now that a new culture of harassment and misuse of procedures is rife on London Underground at the moment and the union will not stand back while individuals are fitted-up and picked off as has happened in this particular case on the Northern Line," said Mick Cash, the general secretary of the RMT.
"RMT members are well aware that the only defence that they have in these circumstances, when the internal machinery has been exhausted, is the unity and solidarity in the workplace.
"RMT remains available for talks as we seek justice in this blatant and clear cut case of victimisation."
London Underground hit back at the union earlier in the year and claimed that the strike ballot breached an agreement the two parties had made.
Nigel Holness, London Underground's operations director for the Jubilee, Northern and Piccadilly lines, said: "To ensure the safety of our customers we operate a zero tolerance policy towards alcohol at work.
"Anyone found to be in breach of this policy faces a disciplinary process and possible dismissal.
"Furthermore, our health and safety procedures are fully in line with medical standards and are representative of best practice in the rail industry.
"The RMT leadership has balloted its members whilst the appeal process is still in progress.
"This is in breach of its agreement with us to exhaust all processes, including ACAS, before balloting members in such cases.
"The result of the RMT leadership's ballot will not influence our decision and will achieve nothing. Any strike action by the RMT will simply lose its members pay."