Members of the Rail Maritime and Transport union (RMT) have announced four strike dates, which will cause chaos for London Underground commuters at the end of the month.
Train drivers will walk out on 19, 27 and 29 June and 1 July, as a protest against the dismissal of their colleague Arwyn Thomas.
Mr Thomas is currently waiting to hear the outcome of an employment tribunal for "unfair dismissal" after he claimed that London Underground (LU) dismissed him for his union activities.
LU denies these charges and claims that it was Mr Thomas's "abusive behaviour" that resulted in his dismissal.
The RMT state that LU's treatment of Mr Thomas is "victimisation", since they have "dragged their heels and failed to reach an agreement" about his returning to work, despite Mr Thomas being granted interim relief at the employment tribunal.
Interim relief effectively converts a dismissal into a suspension with full pay until the final outcome of the employment tribunal.
RMT General Secretary Bob Crow said: "This is a clear cut case of victimisation and RMT calls on London Underground once again to stop the delaying tactics, and the continuing waste of hundreds of thousands of pounds that they have thrown at this case, and get Arwyn Thomas back to work."
LU argues that RMT should not be striking before they have learned the outcome of the tribunal.
A spokesman for Transport for London said: "It is completely mystifying that, having agreed with London Underground that the tribunal process should take its course, the RMT leadership is now threatening strike action again."
Since LU and RMT have failed to come to an agreement, London commuters will suffer. The strikes will take place between 2101 hours on 19 June and 0300 on 20 June, 2101 hours on 27 June and 1159 hours on 28 June, 1200 hours on 29 June and 1159 hours on 30 June, and 1200 to 2100 hours on 1 July.
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