London Underground staff have announced dates for three 24-hour strikes in January and February.
The strikes will take place on January 26 as well as February 15 and 17, as disputes over pay and night tubes drag on.
The RMT union confirmed the news on Monday, with drivers from the Aslef union also promising to join the industrial action.
https://twitter.com/BBCTomEdwards/status/686569575836729348
Overnight tube services were due to begin operating during weekends back in September, but a series of strikes delayed the implementation of the new system.
London Underground staff will once more undertake industrial action over the a failure to agree how the service will work, as well as disputes over pay and work rosters.
RMT general secretary Mick Cash said the union supports the idea of a "properly worked out night Tube service" but added that an "abject failure to work through the detail has led to a comprehensive breakdown in the negotiations".
London Mayor Boris Johnson said: "If a strike goes ahead, it will hit many London Underground workers who do not necessarily support the action, and it will cost the strikers in lost pay."
But Sadiq Khan, Labour's candidate for London's upcoming mayoral election, placed the blame firmly at Johnson's door, saying: "It proves once and for all that the Tory strategy of refusing to negotiate or even meet with the unions makes strikes more likely not less."
