By Alessandra Rizzo and Kate Holton
LONDON, Sept 10 (Reuters) - Hundreds of thousands of Britons took to the streets of London on Monday to cheer Olympic and Paralympic athletes, celebrating a summer of spectacular sport that surprised even the most optimistic by lifting the host nation's mood.
In scenes reminiscent of the Royal Jubilee and the 2011 wedding of Prince William and Kate Middleton, flag-waving fans crammed into the centre of the city to cheer the likes of Mo Farah, Jessica Ennis and David Weir a day after the 45-day event came to an end.
The 800 athletes who rode atop 21 floats were treated to a fly past by the jets of the Royal Air Force's Red Arrows stunt team after winding their way past many of the landmarks that made up the backdrop to the London Games.
"It's been fantastic," said 39-year-old Sophie Edwards, alongside her four-year-old daughter Hannah. "It's been very inspiring - such a good message for the younger generation."
The sense of national pride generated by the successful running of the world's biggest sporting event contrasts with the sense of foreboding that built up before the Games, with the media questioning whether a country still in recession should be paying $14 billion to host a sports event.
A last-minute failure by a private company to provide enough security guards also raised fears about the Games taking place under a heavy military presence as organisers called up extra armed forces personnel to police the event.
Instead the Games were deemed to have given Britain a much-needed lift, although, with years of government austerity ahead, questions remain over how long the feel-good factor will last.
Serving for the last time in his role as London's biggest cheerleader for the Games, the city's eccentric mayor Boris Johnson received the loudest roar from the athletes and crowds as he described the day as the "final tear-sodden juddering climax".
"You routed the doubters and you scattered the gloomsters," he said to cheers. "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."
Many of those who gathered in the streets praised the athletes and the organisers for lifting their spirits.
"Britain has been a rather dull place recently," said Maureen East as her daughter took photos of the passing open-top floats.
"We've had a lot of things going badly, the economy, the weather. This is a ray of sunshine in your life. Coming here seemed the right thing to do to finish it off nicely."
"SEASON OF WONDER"
Some of the loudest cheers were for the thousands of unpaid volunteers who presented a welcoming face to visitors in a city not renown for its public displays of emotion.
"Sunday night marked the end of a season of wonder that seemed to surprise the hosts as much as the guests, a period where we looked in the mirror and were met by an unexpected reflection - one we rather liked," the Guardian newspaper said.
Prime Minister David Cameron, surrounded by volunteers on the doorstep to his Number 10 Downing Street residence, said the success of the athletes and the praise from visitors around the world had given the country a huge boost.
"It's brought the country together. I think 2012 will be like 1966 ... something that will continue to delight us long after this time has passed," he said, referring to England's sole victory at the soccer World Cup.
The host nation finished third in the Olympic medal table - behind the United States and China but ahead of Russia, Korea and Germany - and third in the Paralympic medal table, behind China and Russia.