By Sara Ledwith
LONDON (Reuters) - In the evening sun near Tower Bridge, people watch Olympians on a big screen and cheer. High above them, on the top floor of the bulbous glass building where he has his office, Mayor of London Boris Johnson is addressing technology entrepreneurs in a speech that underlines his ideology.
Why does Usain Bolt run fast, he asks. Competition - that's why.
The excitement of the crowd outside penetrates through the open windows. The blond mop-haired mayor, selling the British capital in a reception in the penthouse, warms to his theme. Another example comes from science.
The 17th-century scientist Robert Hooke, Johnson notes, was also competing fiercely with others in London when he worked out the law of elasticity.
Strain is equal to stress - "as I proved on that zip wire the other day".
The reference - to the minutes when the Mayor of London dangled helplessly from an aerial runway above the assembled crowd in a park - raises a laugh. "Ut tensio sic vis," booms Johnson, offering Hooke's Law in Latin. The audience roars.
Boris Johnson, or plain "Boris" as he is known to most people, seems to be everywhere at the London Olympics. From the 48-year-old's plummy tones encouraging Underground commuters to avoid congested stations to his imitation of Bolt's victory pose, or his prose likening female beach volleyball players to "glistening otters", he has turned 2012 into Boris's Games.
Some say he is an unashamed self-publicist seeking political advantage, some an eccentric, enthusiastic mayor promoting his city. But many pundits believe he ultimately wants the top job.
Britain's current prime minister, David Cameron, went to Eton, the elite fee-paying school, just like Johnson, and shared his Conservative beginnings at Oxford University. Cameron says Johnson "defies all forms of gravity".
In the real world, the economy is struggling and Johnson's critics are angry that his warnings on the Underground have put people off visiting London.
But inside the Games bubble, Johnson, a free-market defender of the banking classes, repeats a relentlessly upbeat story that is attracting the most incongruous support. "I'm incredibly left-wing and I absolutely love Boris Johnson," said Lucy Lapham, a 27-year-old event manager.
"He's come down to our level almost," agreed her friend, Victoria Stickland, 24.
For Alexander Boris de Pfeffel Johnson, who was born in New York General Hospital in June 1964, the London Games kicked off with a trim of the unruly blond hair that gets mussed up on camera, and a promise that the "Geiger-counter of Olympomania" was headed "Zoink!" off the scale.
Handing financial decision-making for London over to local council officers for the duration of the Games, he took to the stage in Hyde Park.
There he promised the crowd "more gold, silver, bronze medals than it takes to bail out Greece and Spain together".
By the opening ceremony, Georgina Wharton, a 30-year old from Melbourne, Australia, said the best thing about Boris was that he is immune to the political correctness she sees everywhere in Britain.
"He just doesn't care," she said admiringly.
On day one of the Games, Johnson was on camera with the Queen, complimenting her for her performance with James Bond in the "magnificent and bonkers" opening ceremony.
By day three, there were headlines about empty seats at Olympic venues. Businesses were blaming his warnings for a slump in their trade.
That evening, Johnson schmoozed representatives from the creative industries to encourage them to invest in London. He and his staff would, he vowed, "kick down the doors" for them.
Investment in the city's infrastructure, including transport, would deliver, he said. He conceded that the capital's economy was "patchy" during the Games but saw an "optimism and a confidence now that is fantastic".
Those who know Johnson say that, beneath the cultivated buffoonery, he is an intelligent, serious politician.
His slapstick moments - including a tumble into a river in east London in 2009 - combine with enthusiasm for the eccentric genius of Britain. A journalist as well as a politician, the twice-married Johnson relies on humour and charm to divert attention from a history of sexual affairs.
He has a deft touch with what he calls the "blessed sponge of amnesia", ensuring that he claims credit while others shoulder blame. When he was first elected mayor in 2008, he won more than a million votes - the largest personal mandate of any politician in British history.
The Conservative Party has not won an absolute parliamentary majority for 20 years, and now some of its members and even some polls suggest he could lead the country, although Johnson dismisses such suggestions as nonsense.
"I think people will look back on these Olympics as a time of great pride," said Tim Montgomerie, editor of a website for Conservative activists. "The whole thing has been magical, and he just seems to have captured the mood."
For Montgomerie, comparisons between Johnson and wartime leader Winston Churchill are not out of place. Like Churchill, he said, "Boris has all kinds of character question-marks about his suitability for the top job, but there is a precedent there, someone who worked out incredibly well".
Many of the London businesses that hoped for a boost from the Games would disagree. Johnson's transport warnings were stopped, but too late for them.
Paul Cunningham, owner of the Biscuit Ceramic Cafe, had expected thousands of Olympic visitors to stroll past every day on their way to the equestrian events in Greenwich, but said crowd management had diverted them. "The end of August is going to be a tricky time, it's scary."
A nearly one-metre-high barrier stretches along the main road. Games stewards wielding huge foam hands urge crowds to follow a direct route to the Olympic site.
Iona Tovey, operations manager at the Black Vanilla ice cream parlour next door to Greenwich's popular market, called the barrier "the Berlin Wall". Since the Games began, sales on some days have fallen more than 50 percent.
In the eaves of London's historic Covent Garden piazza, a year-round tourist hub in the theatre district, Benjamin Pollock's Toyshop is still waiting for the summer crowds who buy its eccentric stock of finger puppets, jumping jacks, antique toy theatres and other trinkets for children.
Shop worker Stephen Fowler, 40, drafted in for extra hours during the Games, said an Australian customer had mentioned that Sydney was equally deserted during its Olympics eight years ago. Why hadn't London planners anticipated that, he wondered.
"It's been a bit of a disaster," said part-owner Louise Heard, laughing. She wants the mayor to help.
"He's the face of London, isn't he? If Boris came out and said tomorrow, ‘You know, the Olympics is great, but hey everyone, go shopping' ... if he's seen falling off a zip wire, then he can come do a stunt in the centre of London perhaps."
To some extent, the mayor's high-wire act distracted the media from less positive stories, including the fact he had invited media baron Rupert Murdoch to an Olympic swimming event.
That day Johnson also gave an interview to Murdoch's Fox News. "It's all going horribly right - touch wood," he said.
The invitation to Murdoch, whose titles are under investigation for alleged phone-hacking by staff, angered Johnson's opponents on the council. Murdoch titles including the Sun have for years been able to make or break political careers in Britain, a fact underlined by the phone-hacking scandal.
As mayor, Johnson is in charge of the police who are conducting the probe into phone-hacking. His opponents were angry. "The mayor is acting in his own interests and not those of Londoners," said Liberal Democrat Stephen Knight.
Where in the old days Cameron would ask Murdoch to use the back door on his visits to Number 10 Downing Street, Johnson was photographed at the Olympic Aquatics Centre with Murdoch, and said the 81-year-old was one of 23 executives he had hosted.
Murdoch's Sunday Times followed the Sun this week with a positive opinion poll about the mayor. It found Johnson would be the preferred choice for 24 percent of voters to become Conservative leader if Cameron stepped down.
In the Olympic Park, orange-clad Dutchman Roger Andriessen, 44, who lives in Britain, said Johnson had been a better ambassador for the Games than even the organisers.
"The headlines have been full of rubbish," he said, referring to British media reports about security problems and slack business during the Games. The mayor, he said, "brushes it aside and says ‘Come on, let's get on with it and have a good time' - I think that's the right attitude."
(Additional reporting by Karolin Schaps and Sophie Kirby; Writing by Sara Ledwith; Editing by Kevin Liffey)