People planning to mark New Year's Eve in London have been urged to plan their journey as a Tube strike from noon threatens to hit most of the network.
New Year's Eve revellers may have to seek alternative transport
Transport for London said it expected "some service on all lines" despite a 24-hour walkout by 4,000 staff.
A spokesman said London's large 24-hour bus network would be expanded further as 40 routes, which usually run during the day, would run through the night.
But people were advised not to drive as roads would be closed for celebrations.
A TfL spokesman said: "In the event of the RMT strike going ahead, we expect there to be some disruption to Tube services, but London Underground intends to run as full a service as it can, throughout the night if possible.
"We expect to be able to provide some service on all lines."
Travellers were urged to plan their journeys carefully, to account for disruption and cold weather.
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Meanwhile paramedics are bracing themselves for what could be their busiest New Year's Eve, as revellers face being left stranded in cold and wet weather.
Russell Smith, deputy director of operations for London Ambulance Service, said: "The service always experiences a huge influx in emergency 999 calls as Big Ben strikes midnight, but this year it fears an even more dramatic surge in demand.
"With such a high volume of people on the streets, the potential for injuries will be even greater."
On Saturday at noon, 4,000 Tube staff are expected to begin a 24-hour walkout.
Union officials refused to attend talks on Thursday to try to resolve the dispute, which centres around new rotas introduced as part of a 35-hour week.
RMT general secretary Bob Crow said the dispute could still be called off, but "time is running out". LU has also said it remains willing to talk to the RMT until the "11th hour".
Mr Crow said his members had voted overwhelmingly to "defend Tube safety, not just for themselves, but for everyone who uses the network".
LU chief operating officer Mike Brown said they would address any specific safety concerns before imposing new rotas and said they would never impose a system that was less safe.
Meanwhile, crowds due to gather in Trafalgar, Parliament and Leicester squares and the Victoria embankment to hear the chimes of Big Ben and see the fireworks, will have to rely on other forms of transport.
Police warned people not to drive into central London as many roads will close at 2000 GMT, when the first "lighting displays" begin, and some parking bays will be suspended.
Those behind the New Year's Day parade, which last year attracted 480,000 people to central London and involves 10,000 performers, have also called on the mayor to lay on extra buses.