Air is something that has proved to be infinitely useful in terms of breathing. Aside from food, warmth and alcohol, it is one of life's essential pre-requisites.

Some people, however, take this too far. The members of a world-wide cult based in California, for example, that believe they can live on air alone, along with sunshine. Their anti-food policy was subject to ridicule early in its life when the leader was caught nipping into a hotel for a chicken pie. Breatharians, as they are known, are now experiencing new popularity and credibility with the appearance of a woman who claims to live off two cups of blackcurrant and vanilla tea a day, as well as the occasional pre-menstrual chocolate biscuit.

Breatharians have droppings like those of rabbits and have a 5000-strong membership.