London 2012: Olympians and Paralympians cheered by crowds

Hundreds of thousands of people have lined the route of a victory parade through London to cheer Britain's Olympic and Paralympic athletes.

Competitors were also honoured with a flypast over Buckingham Palace, the day after the end of the 2012 Paralympics.

Some 800 competitors travelled on 21 floats which made their way through the city over two hours.

Rower Kath Grainger said "we could never have expected this" and swimmer Ellie Simmonds said it was "amazing".

The event near the Queen Victoria Memorial, which followed the parade, kicked off with a flypast, led by the British Airways plane that initially brought the Olympic flame to the UK.

The celebratory show also featured the Red Arrows, performances from Amy MacDonald, the Pet Shop Boys, and speeches from athletes and the prime minister.

It was watched by 14,000 ticket-holders who had made "an invaluable contribution to the Games", including Games Maker volunteers, members of the emergency services, military personnel, competitors' coaches, and support staff.

But the rest of the parade route, starting from Mansion House, was open to all - and many of the athletes on the slow-moving floats expressed surprise at how many people came out to greet them.

A statement from the Mayor's Office said that while no exact figure for the number of spectators was known, hundreds of thousands had turned up for what it described as one of the largest events London had seen.

Six-time gold medal-winning cyclist Sir Chris Hoy said: "I just didn't think it was possible to see so many people out on the streets supporting us... I want to say thank you.

"It's been emotional... If you have to end an Olympic career anywhere this is the place to do it."

Speaking from the rowing team's float, Olympic gold medallist in double sculls rowing Kath Grainger said: "We never really knew how many people would turn up, maybe we thought people would have gone back to work or been fatigued by the last month. But my word, we could never have expected this.

"It is an amazing time to have a celebration with the Paralympic athletes too and a chance to say thank you to all the fans."

London 2012 double bronze medallist Rebecca Adlington - on the swimming float - said: "It's very noisy and crazy down here. We're not far in yet - we're on number 17 so we're quite far at the back. It is incredible. It is so loud."

From the equestrian float, Zara Phillips said: "This is unbelievable. To think everyone has come out for all of us is just amazing. We are so grateful to them."

Paralympic swimmer Ellie Simmonds said: "It's amazing... to celebrate with the public, who are the ones that helped us have that home advantage during the Games."

After the parade, Prime Minister David Cameron expressed his thanks to the athletes - who he called "the heroes".

He told them: "You have given us moments that we will never forget. The whole country salutes your brilliance."

Mr Cameron also thanked "all those who made this possible", including volunteers, the police, and the servicemen and women, who "proved again that you are the greatest in the world".

"Let that spirit that delivered these Games... live on for generations to come."

The prime minister then introduced Princess Anne, president of the British Olympic Association who told the crowd: "What a pleasure it has been to be president of BOA for a home Olympic Games.

"To see so many faces out there of the people who have been critical to producing the stages, platforms and support for these athletes is fantastic. This has been a really remarkable period of time."

Cyclist Sarah Storey said: "The athletes want to thank all the UK as without them we couldn't have done what we did to bring home all this bling."

More than 90% of Britain's medallists, including Mo Farah, Jessica Ennis, and Jonnie Peacock, paraded on 21 open-top floats through the city.

They were grouped by their sports - and travelled in alphabetical order with archers and athletes on the first floats, and weightlifters and the water polo team at the rear.

Olympic diving bronze medallist Tom Daley said: "Today really for me is about, and for the whole team, about going round and giving something back to all the sporting fans, all the people that supported us at the Olympic Games, at the Paralympic Games.

"Hopefully, if we get lots of people out here today, it just really does give you a last kick of the Olympic buzz before it all finishes."

The parade marked the end of eight weeks of Olympic and Paralympic events, which have put London at the centre of the sporting world.

In both the Olympics and Paralympics, the British teams finished third in the medals table. Team GB's Olympians notched up 29 golds, 17 silvers and 19 bronzes. Their Paralympian counterparts collected 34 golds, 43 silvers and 43 bronzes.

The final word of the event was reserved for London Mayor Boris Johnson who said: "We should thank the people without whom the last six weeks would not have made sense and not have been possible: the most successful team of athletes this country has ever assembled.

"My God there's a lot of you," he added, turning to the gathered competitors.

"Every single one of you - this was your achievement, you brought this country together in a way we never expected."

Mr Johnson drew huge cheers and laughter from the crowd during the speech, saying: "You routed the doubters and you scattered the gloomsters and for the first time in living memory you caused Tube train passengers to break into spontaneous conversation with their neighbours about subjects other than their trod-on toes.

"And, speaking as a spectator, you produced such paroxysms of tears and joy on the sofas of Britain that you probably not only inspired a generation, but helped to create one as well."