London Underground workers are to take five days of strike action over the Tube ticket office closures, the RMT Union has announced.
The dispute centres on the closure of all 260 Tube ticket offices and 960 job cuts.
Widespread disruption was caused in February when Tube workers took strike action for one day.
A second day of strike action was postponed at the last minute so that talks could take place.
At the time, the unions, RMT and TSSA, said London Underground had agreed to hold two months worth of talks, which would include a station-by-station review of the ticket office closures.
London Tube strike dates:
– Monday 28 April from 21:00 BST (48 hours)
– Monday 5 May from 21:00 BST (72 hours)