Of course it won’t happen that way; almost certainly it won’t happen at all. Defence officials say that every Olympics since Atlanta in 1996 has had some form of aerial defence component. In truth, media coverage of the missile installations was deliberately confected to reassure Londoners that everything is being done to protect us, and to remind al-Qaeda not even to contemplate trying a re-run of 9/11 over the Thames. And the other point, sources make clear, is that any aerial defence of London cannot rely on a general being instantaneously able to get through on the telephone to the Prime Minister, who might be locked in summit negotiations trying to save the euro, or volleying balls on a tennis court. Shortly before the Games begin, the military will be ‘pre-authorised’ to take the momentous decision to shoot down a civilian airliner, because in the real world, as opposed to a Hollywood film, the decision has to be taken in a handful of seconds. In reality, the fateful, final decision would be taken by a man staring at a radar screen. One really wouldn’t want to be him.