Up to 250,000 people have lined the banks of the Thames in central London to see the New Year's Eve fireworks display and mark the start of 2011.
The 10-minute display had a musical soundtrack for the first time, showcasing some of the most famous songs by British artists.
Crowds gathered on Victoria Embankment and South Bank, but some Tube stations and bus stops faced restrictions.
Red, white and blue fireworks lit up the London Eye in the display.
BBC Radio 1 DJ Nihal oversaw the show, the soundtrack of which included Queen's We Will Rock You, The Beatles' Lucy In The Sky With Diamonds and Blur's Song 2.
After the fireworks display the crowds joined arms to sing Auld Lang Syne in unison.
Erin Wilkins, 26, who had travelled from Sydney, Australia, with Emad Tehrani, 30, to see in the new year in London said the display had been "awesome".
She said: "We've been queuing up here since midday and I think these are the best fireworks I have ever seen.
"I was really good how the fireworks came from three different places."
Peter and Harriet Hughes travelled from Cardiff to see the firework display along with their 18-month-old daughter Phoebe.
Mr Hughes, 28, said: "It's amazing.
"We see it on the TV quite a lot and my wife has never been so we decided to come down. Plus we couldn't find a babysitter."
Twenty-five-year-old Caroline Witossetk came with a group of friends from Germany especially to see the New Year's Eve celebrations on the Thames.
She said: "London is amazing and we are here for three nights, for new year and for the New Year's Parade.
"The people are so amazing, so friendly. It's our first time here in London and we like it."
More than 3,000 police officers were on duty in the capital for the celebrations.
A spokesman for the Metropolitan Police said officers had so far made 77 arrests, 24 of which were for public order offences.
Officers said there was a "huge demand" for public transport and warned that people could have to wait some time before getting on Tube trains or buses.
The spokesman said: "Those who live in London may want to walk a bit further to get to a Tube station - Charing Cross and Waterloo are extremely busy."
Supt Julia Pendry said earlier that the mild temperatures had encouraged many people to join the celebrations.
The organiser of London's celebrations James Donald said the show had taken five months to plan.
London Ambulance Service staff were preparing for one of their busiest nights of the year and said they expected to receive more than 500 calls an hour.
Deputy director of operations Jason Killens asked people to "use the ambulance service wisely and only call us in a genuine emergency".
"Don't call the ambulance service simply because you're drunk, when you're looking to go home."
Revellers were able to travel for free on Tube, bus, tram and train services run by Transport for London until 0430 GMT.
Later on Saturday more than 500,000 people are expected to watch London's new year parade, which is marking its 25th anniversary.