Once upon a time the world was a jolly, happy place. Then the internet came along and spoiled it. That at least is the sub-text of many media reports, especially in the wake of recent so-called “liquid bomb” threat.

The bomb recipes, we're told breathlessly, were found on the internet, conveniently forgetting that most of this stuff - and the chemistry behind it -  has been known about for decades. TNT, napalm, the atomic bomb and C4 are all pre-internet inventions, yet the absence of an internet did little to slow their dissemination - or use.

In a recent piece for The Register entitled Mass Murder In The Skies: Was The Plot Feasible? Thomas C Greene examined the science behind the subject;

We're told that the suspects were planning to use TATP, or triacetone triperoxide, a high explosive that supposedly can be made from common household chemicals unlikely to be caught by airport screeners. A little hair dye, drain cleaner, and paint thinner - all easily concealed in drinks bottles - and the forces of evil have effectively smuggled a deadly bomb onboard your plane.

Or at least that's what we're hearing, and loudly, through the mainstream media and its legions of so-called "terrorism experts." But what do these experts know about chemistry? Less than they know about lobbying for Homeland Security pork, which is what most of them do for a living.

In fact in-flight TATP manufacture is anything but easy. Apart from the raw materials you'll also need to smuggle aboard “several frozen gel-packs..., a thermometer, a large beaker, a stirring rod, and a medicine dropper.” And you'll need to commandeer the loo for most of the flight in order to prepare your concoction.

After a few hours - assuming, by some miracle, that the fumes haven't overcome you or alerted passengers or the flight crew to your activities - you'll have a quantity of TATP with which to carry out your mission. Now all you need to do is dry it for an hour or two...

Greene's analysis is more chilling than any bomb recipe;

...the Hollywood myth of binary liquid explosives now moves governments and drives public policy. We have reacted to a movie plot. Liquids are now banned in aircraft cabins (while crystalline white powders would be banned instead, if anyone in charge were serious about security). Nearly everything must now go into the hold, where adequate amounts of explosives can easily be detonated from the cabin with cell phones, which are generally not banned.

And, of course, you're still allowed to carry on your laptop.