The myth

If you chuck a lit fag-end into a pool of petrol – as we all know from countless filmic explosions – it goes “boom”.

The “truth”

Researchers at the Maryland laboratory of the US Bureau of Alcohol, Tobacco and Firearms set out to test a common arsonists’ excuse: that the fire they’re accused of setting deliberately actually started accidentally when a burning cigarette came into contact with gasoline. Two thousand attempts to set fire to exposed petrol – which included spraying the stuff onto a burning snout – failed to produce a single flame. They tried different brands of ciggy and of petrol, they used a vacuum device to imitate a smoker drawing on a butt, they tried petrol both spread out and concentrated.