The party in Edinburgh - the self-styled Hogmanay capital - has been under way for a number of days already, to build up to the bringing in of the new year.
Events will include fireworks around Edinburgh Castle, live bands and a huge singalong of Auld Lang Syne, which organisers hope will break a world record.
In Cardiff revellers will be able to sleep off their partying in an inflatable tent staffed by medics at the Millennium Stadium.
The sleepover centre has been converted from an emergency chemical decontamination tent.
And in London police are gearing up for one of the busiest nights of the year.
There will be 10 minutes of fireworks at the London Eye, on the banks of the River Thames, and on the nearby Shell building a huge projection will show music, a countdown to midnight and a speech from Mayor Boris Johnson.
The Met's Supt Brian Pearce urged people to plan their night in advance and to take extra care after consuming alcohol.
He added: "Hundreds of thousands of people used to travel to central London when there was nothing for them to see or do.
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