Hundreds of thousands of people lined the streets of the capital today to watch the New Year's Day Parade celebrating the start of the Olympic year.
More than 8,000 performers, including US marching bands, cheerleaders and dancers took part in the 26th annual event.
It began at noon at the Ritz Hotel and followed a 2.2-mile (3.5km) route through Piccadilly Circus, Trafalgar Square and Whitehall before ending at Parliament Square in front of Big Ben.
The Jacksonville State University Marching Southerners, from Alabama, kicked the procession off, followed swiftly by All The Queen's Horses.
Dan Kirkby, communications director of London's New Year's Day Parade, said: "The 26th New Year's Day Parade here in London is a wonderful platform for a fantastic city.
"The first day of 2012, a legendary year for London, and we have got 8,500 performers from all over the world, 19 London boroughs represented, half a million people out on the streets. It's a fantastic day.
"The atmosphere is amazing, it's a great family feast of entertainment and it's all free.
"We have got people from Afghanistan, France, Italy, China, USA and UK performing here today. We've got a huge eclectic kaleidoscope of culture.
"Without doubt this has been the best parade we've done yet, it's a turn of year tradition now and the whole world is watching."
The Queen, who will become only the second British sovereign to reign for 60 years when she celebrates her Diamond Jubilee later this year, had a New Year's message printed in the free guide given to spectators.
She said: "Please convey my sincere thanks to everyone who is involved in the London New Year's Parade this year, for their kind message of loyal greetings.
"I was pleased to learn that the theme chosen for this year's parade will be the Diamond Jubilee and I send my warm good wishes to the instrumentalists, choirs and indeed to all the performers who will be taking part in the occasion. I am sure that it will be a wonderful event."
The crowd was also treated to performances from Strictly Come Dancing contestant Russell Grant and a kite runner from Afghanistan.
Nasser Volant, who fled his native country as a child and now lives near Dijon in France, has been commissioned to make and fly dozens of kites along the route
He is the cousin of Khaled Hosseini, who wrote the novel The Kite Runner which was adapted to become a global film sensation.
His colourful display incorporates more than 20 giant birds of prey and 60 kites carrying the official logo of the Queen's Diamond Jubilee.
Rebecca Brigden, 38, a civil servant from Sutton in London, said: "We are having a fantastic time. It's the first time we have ever been and the children really like the cheerleading so they wanted to see it done properly. We all really liked the donkeys and the little horses too.
"We were here fairly early but we've got a really great spot, being able to see it on the big screen and see them all as they come past."
Rita Haddad, 49, a mother from Boston in America, said: "This is our first time in London and we are enjoying it very much. We did not expect to see such a beautiful city like this.
"It's exciting today but it's not like New York. We like the marching bands and the cheerleaders. The horses are beautiful too, especially the little pony. We loved it.
"Everyone is so friendly, we feel like we are at home."
Tom Tremayne, 46, unemployed from Camden in north London, said: "This is the first time I've been to the New Year's Day parade and it's the first time I've seen American marching bands. We deliberately didn't get too drunk last night so that we could come this morning.
"The marching bands have definitely lived up to our expectations. It's been a really great morning.
"The atmosphere is really good, everyone is enjoying it. It's not too packed which is nice, and you can see everything."