Liquids make explosive mix

While most conventional liquid explosives are too unstable or easily detected to be suitable, several fluids that are not explosive alone can be readily combined to trigger a blast.

A prime candidate for this would be triacetone triperoxide (TATP), the explosive used by the July 7 bombers. Its two raw ingredients are liquids that could be carried on board in containers such as bottles of soft drink. A small detonator could be hidden in an iPod or mobile phone, drawing power from its battery. …

One problem for the bombers is that the solid has to be dried before it becomes a reliable explosive, and it can be difficult to detonate, as attested by the failure of the attempted suicide attacks on July 21 last year. Some formulations, however, would be relatively easy to ignite with a simple detonator, or even a match or lighter.

Dr Andrea Sella [UCL Chemistry] said: "It would be difficult, but I could certainly conceive of these people taking individual compounds, and mixing them together in the loos.

"TATP is something I imagine might be possible to make on an aircraft. You need two lots of liquid, and though these are pretty runny and you'd have to disguise them, it could be possible - contact lens solution is runny. You then get a solid material that is explosive." …

The practical difficulty of assembling and detonating such a bomb on an aircraft means that many attempts would be likely to fail. Dr Sella said: "I do wonder how easy it would be to do in practice. How someone gets up and goes to the loos, with other passengers banging on the door, and does everything right." …

While it would be difficult to blow up an aircraft completely with a small, liquid-based bomb it could be done by concentrating on weak points, such as windows, or by combining several bombs on one aircraft. …

"You wouldn't get the spectacular effect of the plane falling apart in the sky, but if it becomes uncontrollable it is going to end up in the sea five minutes later," Dr Sella said. …

Mark Henderson, 'The Times'