The opening ceremony of the London Games has begun with iconic images of London and Britain being beamed to the world.Tour de France winner Bradley Wiggins, wearing his yellow jersey, rang the largest harmonically tuned bell in the world to start the show.All four countries of the UK were represented in song, as the show capturing the best of Britain began.The three-hour spectacle was viewed by a TV audience of one billion people. Scores of high-profile personalities from around the world attended the opening ceremony at the Olympic Stadium.Rwandan President Paul Kagame was among the world leaders in attendance.A video of James Bond – actor Daniel Craig – meeting the Queen at Buckingham Palace was broadcast to the audience. A helicopter then flew over the stadium to the sound of the Bond theme tune, as two figures parachuted out of the helicopter, one dressed as the monarch.As if by magic, the Queen appeared in the stands at the stadium – part of a crowd of about 80,000 – amid cheers.A Red Arrows fly-past marked the start of the pre-show at the symbolic time of 20:12 BST (19:12 GMT).As the show began, its artistic director Danny Boyle pledged a ceremony with a theme of "this is for everyone".The Oscar-winning film director added that it contains "a celebration of the creativity, exuberance and, above all, the generosity of the British people". He said there were to be "no spectators - everyone in the stadium will be part of the magic".The chairman of London 2012, Lord Coe, earlier told the BBC he was "as excited as hell".Crowds of people, many of them dressed up in their nation's colours, are at the Olympic Park for the show.The BBC's Claire Heald, at the Olympic Park, says transport to the stadium appears to have run smoothly and the crowds moved quickly through security.Rain has started to fall over the stadium, despite forecasters predicting dry weather ahead of the ceremony.The day of celebration began at 08:12 BST (07:12 GMT) with a mass bell ringing. Big Ben rang for three minutes for the first time since King George VI's funeral in 1952.Prime Minister David Cameron said: "It's a great opportunity to show the world the best of Britain, a country that's got an incredibly rich past but also a very exciting future."'Wave of excitement'Mayor of London Boris Johnson told BBC Radio 5 live: "What's so amazing is just the wave of excitement seems to pass from person to person like some benign form of contagion. Everybody is getting it."Tony Blair, who was prime minister when London won the Games in 2005, told the BBC: "It's a party atmosphere but also an immense sense of national pride - of what we are and what we can show the world."The Olympic flame arrived at City Hall on the Queen's rowbarge Gloriana after first weaving through the maze at Hampton Court Palace then being transported down the Thames.The flame's trip around the UK ends with the lighting of the cauldron during this evening's opening ceremony, but the identity of the person who will take on the honour remains a mystery.Europe's largest bell rang inside the Olympic Stadium at 21:00 BST (20:00 GMT) at the start of the opening ceremony, said to be a quirky take on British life.Some 15,000 sq m of staging and 12,956 props are being used, and the event boasts a million-watt PA system using more than 500 speakers.Thousands of fans are also gathered at other outdoor locations across the capital to watch the show on big screens.But the BBC's John Maguire says thousands are likely to be turned away at east London's Victoria Park because of "huge" queues for the London Live event.The Queen and Prince Philip earlier hosted a Buckingham Palace reception for foreign dignitaries, where she wished guests a "successful, enjoyable and memorable Games".