"The explosive was made by mixing two easily obtainable chemicals that can be carried through security in the permitted 100 millilitre containers.

To a security guard, the chemicals - which the Standard is not identifying and cost only a few pounds - are colourless and odourless and seem like water. They can be easily disguised, if necessary, as toiletries.

Dr Sidney Alford, the leading explosives expert who made the bomb for us, said: "Terrorists could easily make this device. They could obtain access to the chemicals without too much difficulty. They're not particularly tightly-controlled liquids."

I'm still waiting for the identity of these magic chemicals, but as I've said all along, my money is on ETD/ETP catching them (the precursors) and that the x-ray is nearly useless for explosives detection purposes.