More than 3,600 police will be on duty in central London when up to 400,000 revellers celebrate New Year's Eve.
Some 350,000 people greeted 2007 in central London
Supt Andy Tarrant, who is in charge of policing the festivities, warned opportunistic thieves they would be caught.
He said plain-clothed police, CCTV and detectives would monitor the event, in addition to the more visible presence of uniformed officers.
Much of central London will be shut to traffic from 1800 GMT on 31 December.
Supt Tarrant said: "If people do turn up intent on committing a crime, our message to them is that they will be arrested and dealt with appropriately."
'Wrap up well'
He warned that partygoers hoping to take their usual bus, taxi or tube home might be disappointed and should be prepared for their journey to take longer than normal.
"People should wrap up well, especially if the weather remains as it is now, because there is a significant chance they may end up in the cold for longer than they expect," he said.
The number of people choosing to celebrate New Year in central London has doubled over the past three years.
In 2006 the main gathering points - along the Embankment, in Trafalgar Square, Leicester Square and the Strand - were filled with people by 2300 GMT, with police restricting access to prevent overcrowding.
As 2006 turned into 2007, some 350,000 revellers watched a midnight fireworks display at the London Eye, despite bad weather.
There were 3,200 police on duty and some 50 arrests for a variety of offences, mainly involving alcohol.