Olympics Correspondent Simon Harris is at a special briefing on the London 2012 Opening Ceremony.
Boyle: Ambition is to keep the show as close to three hours as possible. @londontonight
Show features one hour of culture, athletes' parade, cauldron lighting and fireworks. @londontonight
Boyle on the Olympics: "The biggest thing any country does apart from mobilise for war." @londontonight