Olympics Correspondent Simon Harris is at a special briefing on the London 2012 Opening Ceremony.
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
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Temperatures are expected to get warmer throughout the day with highs of 21C expected to make today the hottest Halloween on record.
But Tower Hill Underground station just a few hundred yards away will be shut because of engineering work on the District Line.