Agree with 'sunny-dave', it's all done for the American TV schedules . We're told to get behind the London Olympics, then the organisers do this to us. It really isn't fair on us Brits!
Also, I read that to get everyone away from the stadium and on to the last trains, they've had to cut great chunks out of the opening schedule so that it doesn't overrun. I pity the people, who at the last minute, after weeks of rehearsals, have now been told to get on their bikes.