- 16 updates
David Cameron described travel disruption caused by the Underground strike in the capital as "unacceptable" on Twitter.
Passengers formed long queues in London Bridge underground station on the first morning of the Tube strike.
Commuters have been told to expect severe disruption, with TfL advising passengers to plan ahead.
A 48-hour Tube strike has created "total chaos" for Londoners just trying to get to work, one commuter has said.
Emily Toner told ITV London that she was forced to hire a Boris bike because of the crowds at Liverpool Street station:
Thousands of staff and volunteers are working hard to keep the capital working during the "pointless" Tube strike, London Underground said.
TfL said the Victoria line was now running fully with the Central line running to Holborn and the Jubilee line running through from Wembley Park to Stratford.
London Underground managing director Mike Brown said:
A Transport for London spokesman said the RMT could not "claim a shut down in any sense of the word."
Commuters have reported having to wait a long time for black cabs at Paddington station this morning.
Staff at the station warned passengers to expect lengthy queues yesterday.
London Overground services will be unaffected by strike action but trains and platforms are expected to be far busier than usual, TfL has said.
Transport for London said its ambassadors will help keep Tube stations open and passengers on the move during the 48-hour walkout by London Underground workers.
TfL said a record 7,961 buses were running in London after 266 were added to the service.