Transport for London (TfL) chiefs are in defiant mood today, labelling a Tube strike which has caused chaos an gridlock in the Capital's streets as "pointless".

London Underground is operating train services on nine lines on day one of the 48 hour strike called by the RMT union in protest at planned ticket office closures.

Some 266 additional buses have been laid on - bringing the total on the streets to 7,961, the highest number of buses ever operated in London - and staff and volunteer 'travel ambassadors' drawn from TfL’s support functions have been deployed to the frontlines.

The strike began at 9.30pm on Monday night and will last until Wednesday night. A further three days of industrial action is scheduled to begin next Monday evening (May 5).

Mike Brown, managing director of London Underground, said: " Thousands of staff and volunteers are working hard this morning to keep London working and our customers informed in the face of this pointless strike. More London Underground staff have come to work this morning than during the strike back in February, and a record number of London buses are operating.

"Only the RMT leadership know the real motivations behind their action, but it is infuriating that London's commuters and businesses are the ones who are being forced to pay the price with five days of disruption."

TfL say its 'modernisation' plans which would see ticket offices closed, will save £50million a year which will be 'reinvested in more frequent and reliable train services and help keep fares down'. A t the busiest stations there will be nearly a third more staff visible and available to provide, on a permanent basis, the face-to-face customer service offered during the London 2012 Games, TfL claim.

Mr Brown added: " My message to the leadership of the RMT is that we will not be diverted from doing the right thing by our customers and staff. They should call the strike off and instead work with us to help shape the future of the Tube."

The RMT described support for the strike as "solid".  Its a cting general secretary Mick Cash said: "RMT could have recommended the suspension of this strike action if LU had responded positively to our proposal to halt the ticket office closures and job cuts, stopping the dire impact they would have the length and breadth of London Underground.

"As a consequence of the management stance, and the broken promises of Boris Johnson, the action has gone ahead and is solidly supported. RMT remains available for serious and meaningful talks around our alternative proposals."