A strike by London Underground workers in a row over safety closed Tube stations today and is set to escalate, threatening further travel disruption for tens of thousands of commuters.
London Underground insisted that the walkout by station staff had little impact on services, closing 24 stations by 9am.
But the Rail Maritime and Transport Union accused LU of underplaying the effect of the industrial action and said there had been widespread travel chaos this morning.
LU said 11 out of the 12 Tube lines were running a good service, with only the Northern line facing delays because of a separate dispute over the sacking of a driver.
An LU spokesman said: "The RMT strike has had a minimal impact on services.
"At the height of the morning peak less than 10% of stations were closed due to industrial action.
"The vast majority of our staff our working normally."
The company said 90 per cent of its station staff had signed up to a deal giving them a 35-hour week and 52 days' holiday which was at the centre of today's strike.
The RMT said the 24-hour walkout, which began at 6.30pm last night, had been solidly supported by thousands of its members and warned that the dispute was set to escalate.
The union accused LU of ignoring safety rules and of using untrained staff and managers to keep stations open.
"It is clear that LU's attempts to run a network without adequate station staff is putting the public at risk," said regional officer Bobby Law.
The union said it will be balloting its entire Tube membership for industrial action over alleged health and safety breaches since the strike started and because of similar alleged incidents during a previous walk out over New Year's Eve.
The RMT claimed there were delays on most lines and said that at one point this morning around half of the 108 deep stations covered by fire regulations were closed.
London Underground strongly denied it was compromising safety and hit back at the union, claiming it was making untrue statements to justify the strike.
Delays on the Northern line were caused by an unofficial strike by drivers demanding the reinstatement of a sacked colleague.Reuse content