London Underground workers started a 48-hour strike tonight in a row over ticket office closures, threatening travel chaos in the capital - despite a flurry of last-ditch efforts to head off the action.
Members of the Rail, Maritime and Transport union and the Transport Salaried Staffs Association walked out at 9pm, and will strike from the same time next week, leading to disruption to Tube services until Friday morning.
Train passengers were also warned of problems tomorrow because of a return to the wet and windy weather which has devastated travel across the UK.
Southeastern trains said the forecast weather, after the wettest January for a century, presented a risk of further flooding, landslips and falling trees.
As a result, Network Rail has put in place a 40mph speed restriction across parts of the Southeastern network from 11pm tonight until tomorrow evening.
Tube union leaders continued to attack London mayor Boris Johnson today, saying he was refusing to meet them to discuss plans to close all Tube ticket offices, with the loss of several hundred jobs.
Bob Crow and Manuel Cortes, leaders of the two unions, went to City Hall to try to confront the mayor - who was broadcasting his weekly phone-in show on LBC.
Mr Crow, speaking on his mobile phone on-air from outside City Hall, told the mayor: "We are not here to score points - all we want is an opportunity to negotiate about the Tube. We are asking you to listen to our point of view. We would love to call the strike off."
Mr Crow accused the mayor of refusing to suspend the ticket office closures.
Mr Johnson replied: "That is complete nonsense. We are more than happy to engage on these issues.
"Of course there are job losses involved but there are no compulsory redundancies. We have already had more than 1,000 people showing an interest in voluntary redundancy.
"Call off this pointless strike which will do nothing other than cost your members their wages."
Mr Crow said a form had been sent to staff outlining the job cuts, and if it was suspended the industrial action would not go ahead.
TfL said its recent polling showed that when it is explained properly, 82% of Londoners backed the ticket office changes.
Speaking before the announcement that strike action was going ahead, Labour leader Ed Miliband said he hoped it could be averted.
"I think that both sides need to do proper negotiations about these issues," he said.
"I think its deeply regrettable that there doesn't seem to have been any negotiations or any meetings with the mayor of London and Transport for London about these issues.
"They need to get round the table and stop the inconvenience that will be caused to commuters across London."
Simon Thomas, chief executive of Hippodrome Casino in Leicester Square, said it was "frankly embarrassing" that the ICE gaming industry exhibition at the ExCeL Centre would be disrupted by the industrial action.
"Gaming industry executives from across the world are in London this week and it is outrageous that this strike is being held."
The mayor's official spokesman said: "Mr Crow and Mr Cortes are now grandstanding. If they were really serious about meeting the mayor they wouldn't have called a strike in the middle of a consultation, a strike that 70% of members haven't voted for.
"Instead they could have engaged constructively with TfL (Transport for London) before we ever reached Acas, where only yesterday they refused a fresh offer of dialogue which would involve extending the consultation period. The mayor's door is open if they call off this pointless strike."
LU said it will run as many services as possible during the strikes, but warned there will be disruption until Friday morning.
Special notices were displayed at Tube stations giving details of the likely impact of the industrial action.
Some services are likely to operate between 7am and 11pm tomorrow and Thursday, with no services outside those times.
LU said it will keep as many stations open and run as many trains as possible, but urged passengers to check before they travel.
Among the likely impact will be Bakerloo Line trains not stopping at stations such as Embankment, Piccadilly Circus and Regent's Park; no Central Line or Piccadilly Line trains through the central areas; no District Line trains stopping at stations such as Sloane Square, Temple and Blackfriars; no Hammersmith and City Line trains stopping at Barbican, Euston Square and Great Portland Street; no Jubilee Line trains stopping at Bermondsey and Southwark; no Metropolitan Line trains stopping at Euston Square and other stations; Victoria Line trains only running between Seven Sisters and Victoria; and Northern Line trains not stopping at several stations including Leicester Square, Oval and Clapham North and South.
Around 100 extra buses will be laid on, while normal services will run on London Overground and Tramlink.
TfL said it will delay roadworks, but the capital's congestion charge will remain in force.
Tube services were disrupted for the rest of the evening after the strike started, with some lines suffering severe delays.
TfL said the Circle, Hammersmith and City and Metropolitan lines were among those worst affected.
The biggest impact will be felt tomorrow.