According to 'sources' more ambulances were stolen during the Olympics than usual. The security services were apparently concerned this might indicate an al Qaeda attack was imminent. Why al Qaeda would want to draw attention to themselves by stealing lots of ambulances and why they would leave it to the last moment to execute these thefts is not explained. But then that was the Olympics and the authorities might also have thought it a good idea to put missiles on top of some blocks of flats and shoot down civilian jets over the city!