A TV audience of one billion people worldwide is anticipated for the London 2012 Olympics Opening Ceremony later.

We know cyclist Sir Chris Hoy will carry the British flag into the stadium, but iwho will light the Olympic flame at the venue is being kept a closely guarded secret.

Sir Roger Bannister - the first man to run a four minute mile - and rower Sir Steve Redgrave - are the favourites, with Prince William and even The Queen also mentioned by some.

Whoever it is - Prime Minister David Cameron and Labour leader Ed Miliband agree tonight's ceremony is the biggest
advert for Britian in decades: