Union leaders clashed with London Underground tonight over the impact of strikes which caused travel misery in the capital.
The Rail Maritime and Transport union said 24-hour walkouts over job losses set to end at 9pm were "solidly" supported and had crippled Tubes, leading to a "skeleton" service, or none at all on some lines.
And they are threatening more disruption in the coming months.
But Transport for London (TfL) maintained that well over a third of Tube trains ran despite the strike.
Commuters walked, cycled, shared a taxi or joined long queues for a bus to beat the action by members of the RMT and the Transport Salaried Staffs Association, who are protesting over plans to axe 800 jobs, claiming the cuts would affect safety.
Three further 24-hour strikes are planned to start from the evenings of October 3, November 2 and November 28, although it is likely that fresh talks will be held in a bid to avert more disruption.
Business leaders said the strike cost the economy almost £50 million, with firms paying for staff to stay in hotels, laying on alternative forms of transport, or allowing people to work from home.
RMT general secretary Bob Crow, who joined a picket line at Euston, said TfL's figures on the level of services were a "complete fabrication", adding: "They have claimed to be running a full service on lines where large numbers of stations have remained closed all day.
"It is time the Mayor instructed his transport officials to take this safety issue seriously, drop his cuts and open up meaningful negotiations with the unions over the future of a safe and secure Tube network."
London Mayor Boris Johnson cycled to the Stock Exchange in the City to speak at the opening session of the Capital Markets Climate Initiative as the effect of the strike took hold during the morning rush hour.
He said the staffing proposals were "moderate and sensible" and accused the unions of "cynically deciding to try the patience" of commuters.
Mike Brown, LU's managing director, said everything was done to keep as many Tube services operating as possible, adding that the city was not paralysed.
"The RMT and TSSA leaderships have chosen to disrupt Londoners for no good reason. The safety argument they now deploy - which has never been raised in any formal forum - is completely without foundation. It is simple scaremongering designed to mask their wish to strike.
"Londoners will doubtless find it incredible that the two union leaderships are pursing this action when they have been given cast-iron assurances that the staffing changes we are making come with no compulsory redundancies, that every station that currently has a ticket office will retain one, and that every station will remain staffed at all times."
Transport Secretary Philip Hammond said: "These Tube strikes will be bad for passengers, bad for business and bad for London.
"At a time when public finances are under pressure, any strike by Tube workers will be seriously damaging - undermining the case we are making within the spending review for continued investment in the Tube."
:: Commuters suffered more misery when rail services into London Waterloo were disrupted this morning after a lorry struck a railway bridge at Haslemere in Surrey, leading to delays, cancellations and over-crowding on South West Trains services.