Terror plot scenario "untenable"

"The idea that these people could sit in the plane toilet and simply mix together these normal household fluids to create a high explosive capable of blowing up the entire aircraft is untenable," said Lt. Col. Wylde, who was trained as an ammunition technical officer responsible for terrorist bomb disposal at the Royal Army Ordnance Corps in Sandhurst.

After working as a bomb defuser in Northern Ireland, Lt. Col. Wylde became a senior officer in British Army Intelligence in 1977. During the Cold War, he collected intelligence as part of an undercover East German "liaison unit," then went on to work in the Ministry of Defense to review its communications systems.

"So who came up with the idea that a bomb could be made on board? Not Al Qaeda for sure. It would not work. Bin Laden is interested in success not deterrence by failure," Wylde stated.

"This story has been blown out of all proportion. The liquids would need to be carefully distilled at freezing temperatures to extract the required chemicals, which are very difficult to obtain in the purities needed."

Once the fluids have been extracted, the process of mixing them produces significant amounts of heat and vile fumes. "The resulting liquid then needs some hours at room temperature for the white crystals that are the explosive to develop." The whole process, which can take between 12 and 36 hours, is "very dangerous, even in a lab, and can lead to premature detonation," said Lt. Col. Wylde.

If there was a conspiracy, he added, "it did not involve manufacturing the explosives in the loo," as this simply "could not have worked." The process would be quickly and easily detected. The fumes of the chemicals in the toilet "would be smelt by anybody in the area." They would also inevitably "cause the alarms in the toilet and in the air change system in the aircraft to be triggered. The pilot has the ability to dump all the air from an aircraft as a fire-fighting measure, leaving people to use oxygen masks. All this means the planned attack would be detected long before the queues outside the loo had grown to enormous lengths."

Government silent on detonators

Even if it was possible for the explosive to have been made on the aircraft, a detonator, probably made from TATP, would be needed to set it off. "It is very dangerous and risky to the individual," Wylde said. "As the quantity involved would be small this would injure the would-be suicide bomber but not endanger the aircraft, thus defeating the object of bringing down an aircraft."