General Sir Nick Parker, in charge of the military's Olympics role, said the security exercise would prepare for the possibility of "extreme threats".
– General Sir Nick Parker
What we need to do is make sure we practise against those high-end threats but they are not considered to be likely.
What I'm doing is testing my systems so I'm reassured that, should they become more likely, we can react.
One would want the world to know that we are taking security for the Olympics seriously.