Ambulance crews in the West Midlands said they had their busiest new year yet, receiving 1,269 emergency calls in the first three hours of Friday.
A spokesman said the busiest time was from midnight to 0300 GMT, with a call on average every nine seconds.
South East Coast Ambulance Service said it received 1,080 calls during the last two hours of 2009 and the first four hours of 2010.
The service, which handles 999 calls across Surrey, Sussex and Kent, said most of the call-outs were for falls, breathing difficulties or injuries in fights and assaults.
In Edinburgh, partygoers watched a firework show above the castle, followed by a laser and light display in Princes Street.
Earlier, those attending the Concert in the Gardens were entertained by 80s band Madness and pop act Noisettes.
Three stages along Princes Street provided entertainment by bands including Indie rockers We Were Promised Jetpacks and rock band The Enemy.
People had travelled to the city from around the world.
Jenna Tolley, 20, from Wollongong in New South Wales, Australia, said: "The atmosphere is great and all the people really friendly."
Across Scotland, ambulance staff had their busiest night of the year as the country welcomed in the new decade.
The Scottish Ambulance Service said it dealt with 2,247 calls in the first seven hours of the new year - up 5% on last year.
A large number of the call-outs were for alcohol-related incidents.
Pete Irvine, creative director of the Edinburgh event, said it had been an "extraordinary night" in the city, "with brilliant music, a magical fireworks display against a full moon sky and the dramatic castle slopes dotted with snow, and a friendly and euphoric atmosphere that you won't find anywhere else in the world."
The street party is the highlight of a five-day Hogmanay Festival in Edinburgh, featuring a torchlight procession and dance and music events, which ends on Saturday.
In Glasgow revellers packed into George Square for the city's sell-out Hogmanay party, headlined by Deacon Blue.
Celebrations are held at the London Eye every New Year's Eve
In Aberdeen a fireworks display was held over His Majesty's Theatre at midnight, while the streets of Stonehaven, in Aberdeenshire, were lit up by the 150-year-old fireball festival.
The event in Inverness was cancelled as road and pavement conditions were considered too treacherous.
Ch Insp Andrew MacLean, of the Northern Constabulary, said: "For reasons of public safety, we made a recommendation to the organisers and they have decided to cancel the Hogmanay party."
Meanwhile, the closure of Inverness airport meant several hundred passengers had to find overnight accommodation in the city.
However, 16 opted to stay in the terminal to see in the new year with champagne and pizza.
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