MILLIONS of commuters and other passengers were facing travel misery as a strike by rail workers caused major disruption to London Underground services.

The Rail, Maritime and Transport union said every Tube line in the capital was suspended or running only a skeleton service after "rock solid" support for a series of walkouts.

Thousands of members of the RMT and the Transport Salaried Staffs Association walked out on Monday night for 24 hours in protest against plans to axe 800 jobs.

London Mayor Boris Johnson cycled to the Stock Exchange in the City to speak at the opening session of the Capital Markets Climate Initiative, and 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: "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."

RMT general secretary Bob Crow, who joined a picket line at Euston station, said: "Our members have shown in their rock-solid support for this action that they will not sit idly by while staffing levels are hacked to the bone and the management open the door to a major disaster."

LU said later that nearly 40% of Tube trains were operating, despite the strike.

"Some 194 out of a total of 500 Tube trains are in operation, providing a service on all but one of London's Tube lines," said a spokesman.

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."