After the ceremony, Mr Johnson addressed Team GB athletes and told them he did not want to hand the Olympic flag back.
"I want you to know it was very, very hard just now to hand over that Olympic flag to Jacques Rogge," the mayor of London said.
He asked the athletes whether they thought he should have tried to keep it and then joked: "Did you see I yanked it back and he kind of flinched."
He told the British sportsmen and women they were part of the "greatest team of athletes this country had ever assembled".
"Team GB of 2012, you have achieved fantastically," he said.
Boris Johnson has dismissed talk of him becoming the next Prime Minister: "How could anybody elect a prat who gets stuck in a zip wire?"Read the full story ›
The Mayor of London has been photographed doing a 'Bolt'.
Here is Boris in the signature pose of the 100 metre champion Usain Bolt.
The Mayor visited fire crews today at the Olympic park - and posed for the photo. It was tweeted by the Commissioner of the London fire brigade.
Boris Johnson joined army officers at Tobacco Dock earlier showing his support for our Olympic rowers. He watched Londoner George Nash and his rowing partner Will Snatch clinch a bronze medal in the men's pair.
The Mayor of London, Boris Johnson will be in Tottenham visiting offices that were burned down during last summer's riots. He'll be joined by Spurs player Ledley King and MP David Lammy to see how a 41 million pound regeneration programme is helping to restore the area.
Transport for London has today issued contingency travel advice for tomorrow's strike.Read the full story ›
A senior BBC political journalist has been appointed as London Mayor Boris Johnson's communications chief.Read the full story ›
London mayor Boris Johnson will see fighting skills put to the test today as he meets young people involved in a police scheme to learn martial arts.
The Team TKO scheme in Merton, south London, is designed to steer young people away from crime and anti-social behaviour.
The seven-week course for 11 to 18-year-olds offers an introduction to several martial art disciplines including karate, boxing, muay thai, taekwondo, judo, jiu jitsu and mixed martial arts.
Good news for older Londoners who want to get round their home city:
Mayor Boris Johnson says "the plan is" to reduce the age of the Freedom Pass (free travel) back to 60 by September this year.
"It will make London even more different to other cities in the UK".
At the start of his first Mayor's Question Time, Boris Johnson addressed the 25 members of the London Assembly - some of them there for the first time. He said "We're very lucky to be here in 2012... because this is going to be, and already is, one of the greatest years in the memory of this city".
Before going on make a plea for GLA business to be conducted, let's say, on a 'higher' plane. Or as he put it "with the minimum possible recrimination, rancour and bickering".
Seconds later, Jenny Green, the Green Party's candidate for Mayor, accused him of "pedalling pseudo facts" and "sticking his head in the sand" over the issue over air-quality".
Hardly surprising then that another Assembly member was soon heard muttering "same old, same old"...