London's mayor has come under fire for not standing up to Tube strikers as the capital's underground network grinds to a halt.

Ken Livingstone, like millions of other London commuters, walked to work on Thursday morning.

But unlike many long suffering passengers he does not blame the militant Rail Maritime and Transport union for the disruption.

The strike is set to cost business £60 million.

The mayor - who appointed the hard left RMT chief Bob Crowe to the board of Transport for London - blames government privatisation plans for the strike.

Tube staff are striking over claims that unions were not consulted on privatisation safety.

Last week, the Health and Safety Executive ruled that the PPP would be safe.

Many believe the dispute is cover for an unlawful political strike in opposition to the government's controversial PPP for London Underground - action that the former left-wing GLC chief, then dubbed "Red Ken", appears to back.

"The PPP repeats on the Underground the same fragmentation that contributed to the tragedies on the national rail network and at potentially very large cost to the London. This is why it is being imposed on the city against the wishes of the great majority of Londoners," said Livingstone.

"Its malign consequences are worsening all fields of the transport system in London including leading to industrial action.

"The best way to prevent conflicts like the present is for the government to withdraw the PPP."

The mayor's stance will not endear him to Millbank fixers ahead of a key national executive vote on his future Labour membership next Tuesday.

And the Labour chairman of the Greater London Assembly's transport committee has attacked Livingstone for letting down Londoners.

"The mayor has a responsibility to stand up for Londoners. He should be challenging and trying to stop the action rather than blaming the PPP," said John Biggs.

Livingstone's stance is also at odds with that of his transport commissioner, Bob Kiley.

"While it's no secret that I have serious concerns about Tube safety under the PPP, strike action is unlikely to help keep the support of London's travelling public," he said.

"I urge the parties to return to the negotiating table and the government to drop their discredited Tube PPP plans."