A strike over planned job cuts by rail workers is causing major disruption to commuters on London's Underground services.
The walk-out is over plans to cut 800 jobs from the workforce of 19,000.
The Rail Maritime and Transport union has said every London Underground line is running a skeleton service.
On a normal weekday, passengers make about 3.5m journeys on the Underground.
Commuters were forced to join long queues for crowded bus and boat services, as all of the network's 11 lines were either suspended or badly disrupted.
Thousands of members of the RMT and the Transport Salaried Staffs Association walked out last night for 24 hours, threatening travel chaos until tomorrow morning, in protest at plans to axe 800 jobs.
Contingency plans were put in place for dealing with the strikes, with 100 extra buses, escorted bike rides, marshalled taxi ranks, and capacity for 10,000 more journeys on the River Thames today.
Transport for London maintained that services were running on a number of lines and said people were able to travel around the capital because of its contingency plans for dealing with the industrial action.
Volunteers were positioned at Tube, bus and rail stations to help people with their journeys and provide maps and other information.
London Mayor Boris Johnson cycled to the Stock Exchange in the City to speak at the opening session of the Capital Markets Climate Initiative.
Mr Johnson said new staffing proposals were 'moderate and sensible' and accused the unions of 'cynically deciding to try the patience' of commuters.
Mike Brown, London Underground's managing director, said: 'We are doing everything possible to keep as many Tube services operating today, and to keep Londoners moving by providing extra buses, river services, and other alternatives.'
The Tubes Union: RMT has said that 'the message to the Mayor and his transport officials is clear - stop playing fast and loose with safety, stop the drive towards unstaffed stations, drop the threat of these lethal cuts and start meaningful talks on a safe and secure future for the London Tube system.'
A Transport for London spokesman said a 'stuttering' service was expected to follow the end of the strike at 9pm tonight.
