London Underground workers are to stage five days of strike action in the coming weeks in the long-running row over Tube ticket office closures.
Members of the Rail, Maritime and Transport (RMT) union will walk out from 9pm on Monday April 28 for two days and again from 9pm on Monday May 5 for three days.
The first two days of action will take place ahead of a May Day event in London in memory of former RMT leader Bob Crow, and politician and campaigner Tony Benn, who died within days of each other last month.
The union claimed that long-running talks hosted by the conciliation service Acas, aimed at settling the dispute over the closure of ticket offices and subsequent job losses were "wrecked by a combination of management intransigence and the introduction of additional measures" the union said worsened the original plans.
A statement said: "It has also been made crystal clear to the union that this is just a first tranche of cuts with even harder attacks being lined up for the near future."
RMT acting general secretary Mick Cash said: "The talks aimed at resolving the dispute on London Underground over the savage cuts to jobs, services and safety have been cynically wrecked by a Tube management who not only refused to budge an inch but who have chosen to up the ante by injecting further poisonous measures into a package that was already toxic to the core.
"Staff are furious that while senior management pay and staffing levels are being allowed to roar ahead the jobs and pay of the core, station based staff who are the interface with the travelling public are being torn to ribbons.
"The assurances that were given at the time RMT suspended the original action for a proper evaluation of the cuts plans have been ripped up and thrown back in our faces.
"An opportunity to resolve this dispute through eight weeks of talks hosted by Acas has not only been missed, it has been sabotaged.
"As a result, RMT has no option but to put on further strike action in the expectation that the management will now halt these dangerous cuts plans and engage in meaningful and serious talks on the future of a tube network running at full tilt, with further demands in the pipeline, which needs more staff and not less to operate safely."
Workers went on strike earlier this month but action was put on hold while talks were held.