I am convinced that the laptop obsession derives from movies. (It won't be the first time that US defence policy has come from the suggestion of a movie.)

There has never, ever been a case of commandeering an aircraft, exploding an aircraft, or anything else involving a laptop computer.

The only electronics involved in air sabotage have been a Toshiba radio (Pan Am 103) and a Casio wristwatch (Philippine Airlines.). Both items worked if they were turned on. The wristwatch contained no explosives.

But computers seem somehow scarier and more powerful. They are the kind of equipment unfamiliar to ageing former cops who write TSA policies.

Although the shoe obsession is absurd, at least it was based on an actual incident. The danger of laptops is entirely within the imagination of myopic bureaucrats at the TSA.

Perhaps the TSA will tell us that they have "credible" information that is "highly classified" about the dangers of laptops. It's about as credible as the warnings regarding Al Qaeda scuba attacks, poisoned ink pens, unmanned aircraft, poisoned prescription drugs, the list goes on and on.