It took four days, but four days in, the fears about the fragility of London's public transport network came true.
One of the key tube lines to reach the Olympic Park here was suspended for hours this morning, the delays hitting spectators and commuters alike.
It was the first real test for Londoners still working in the city while the Games go on. It comes as more and more businesses are complaining that the Olympics has actually caused a big fall in trade. Our Olympics Correspondent Simon Harris on the faliure on the Central Line.