Revellers are being urged to plan their journeys home
London is gearing up for the busiest night of its social calendar - the New Year festivities.
Police said a dedicated operation would be in place to cover the fireworks display along the banks of the River Thames near the London Eye.
Revellers were warned to carefully plan their route home and to dress warmly.
There will be extensive road closures and access to some Tube stations would be limited. Tube trains will run until 0430 GMT and travel home is free.
But Transport for London has warned that due to crowd control measures, several stations will be exit-only close to midnight, including Charing Cross, Covent Garden, Leicester Square and Westminster.
Travel on all of London's public transport will be free from 2345 GMT until 0430 GMT in an effort to get people home safely.
Road closures across central London will take effect from 1800 GMT and police warn against driving into the city.
Extra police will be deployed in popular gathering spots, including Leicester Square and Trafalgar Square, where police will be on raised viewing platforms to oversee festivities.
"Keep an eye on friends and family you're out with and remember that drinking too much can make you vulnerable to becoming a victim of crime," said Supt Brian Pearce.
He warned party-goers to be aware of criminals and pickpockets working the crowds.
About 180,000 people are expected to descend on the river bank to watch the fireworks display organised by the mayor's office.
Police estimate that city streets will fill with an additional 200,000 people heading to clubs, bars and house parties.
The 10-minute fireworks display will kick off after midnight is sounded by the chimes of Big Ben.
Ahead of midnight, there will also be new year wishes projected on the side of the Shell Building on the South Bank, led by Mayor Boris Johnson.
Mr Johnson's message will be one of "enthusiasm and hope" despite the economic gloom hanging over the city.
He said: "I can think of no better city to spend New Year's Eve and these fireworks will remind Britain and the world of the joys and charms of this city all year round."
British Transport Police Ch Supt Dave Wildbore said: "While Tube services will be running all night they will be extremely busy and it's likely you'll have to queue for a long time outside the station, so dress warmly for waiting in the cold weather and please be patient."
London Ambulance Service will set up a field hospital in Waterloo station to help the service cope with people who have over-indulged and need medical attention.