An interesting point in the Letters page of yesterday's Torygraph :
Your average terrorist fanatic wanting to punish the British infidels has only to check into a flight as a passenger from a BAA airport (a form of martyrdom in itself). Chances are his explosive-packed bag will be lost like thousands of others, and will not travel on his aircraft. It will blow up somewhere in the middle of LHR, or possibly on one of the cargo aircraft flying all the lost baggage around the world, causing confusion and alarm for the forseeable future ......