Both the Central Line and Waterloo & City Line are not running today due to strike action.
The strikes started at midnight after the RMT and Aslef unions voted for action to address industrial relations between drivers and Transport for London (TfL) that it claimed was at “breaking point”.
The action will go on until midnight tonight.
Separate action on the Piccadilly Line was averted in last-minute talks between TfL and RMT.
That strike would have started at 1.30pm today, lasting until 3pm Thursday.
Commenting on the Central Line strike, RMT general secretary Mick Cash said: “A conscious decision to up the ante by attempting to single out and pick off individual members of staff, has tipped the situation over the edge and has led to the announcement of strike action.”
TfL has said that both RMT and Aslef industrial action was a result of it refusing to reinstate two drivers sacked following alleged safety breaches.
Nigel Holness, director of network operations for London Underground, said: “The strike action called by Aslef on 7 November is totally unjustifiable. The union is demanding the reinstatement of a Central Line driver sacked over a serious safety breach after deliberately opening the doors of a train in a tunnel.
“We always strive to run a reliable service for our customers but our commitment to the safety of both customers and staff is absolute and something we will never compromise on.”
Commuters also face trouble on TfL Rail this morning, which is running with severe delays between Paddington and Heathrow Airport due to a faulty section of track.