Revellers hold up a Union Jack flag during a screening of the official handover of the Beijing Olympic Games to London in front of Buckingham Palace in London August 24, 2008. [ Agencies]

LONDON--The Olympic handover flags were raised on Sunday in more than 400 venues across Britain to celebrate the moment London becomes the next host city.

"The Sing The Nation, The Sing London" event, taking place across Britain, featured songs connected to each region, including Manchester, Birmingham, Liverpool, Edinburgh, Belfast and Cardiff.

Each London borough held a flag-raising ceremony and there were street parties and festivals. The banners went up at about 2:06 p.m. local time as Boris Johnson, Mayor of London, was handed the Olympic flag at the closing ceremony of the Beijing 2008 Games.

As the flags were raised, 40,000 people gathered in the Mall in the front of the Buckingham Palace in London for the Visa London 2012 Party.