Commuters face severe disruption on the London Underground after two transport unions announced plans to take strike action next week over plans to close Tube ticket offices.
The TSSA union said its members voted to join two 48-hour strikes by the RMT union.
According to Get West London, the industrial action is over Mayor Boris Johnson's plans to close all 260 Tube ticket offices and making around 1,000 redundancies.
The strikes are set to take place between February 4 and 6, and again from 11 to 13 February.
TSSA union general secretary Manuel Cortes said: "It is now time for Boris to sit down with his staff representatives and negotiate a sensible deal which will protect the safety and security of the travelling public as well as the long term interests of our members."
Writing to commuters, customer experience and communications MD Vernon Everitt of TfL said: "RMT and TSSA unions have called two 48‑hour Tube strikes over changes we are proposing to make to our services.
"If the strikes go ahead, they will start from 21:00 Tuesday 4 February until 20:59 Thursday 6 February and from 21:00 Tuesday 11 February until 20:59 Thursday 13 February.
"The changes that we are proposing to make will mean more staff will be visible and available, with stations staffed and controlled at all times services are running. We will introduce a 24‑hour service on core parts of the Tube at weekends from 2015."