In the modern world, is it offering some small advantage to the likes of Nicole Kidman, Chris Evans and Charlie Dimmock.'Experts in genetics always describe their science as being about the way in which eye and hair colour is passed from parent to child,' said Professor Rees.'In reality we know little about the inheritance of these characteristics apart from the way red hair is inherited.

This helps to prevent rickets, a disease which progressively weakens bone structures, and the lung disease tuberculosis, which can be fatal.

Professor Jonathan Rees, of the University of Edinburgh, speaking at a series of seminars on hair in London yesterday, said the ginger gene may have had a significance throughout history.

Did their ginger hair, for instance, assist in the achievements of Napoleon, Cromwell and Columbus?

What effect did it have on the exploits of General Custer, Florence Nightingale, Cleopatra, Nell Gwynne and Rob Roy?

It is not the image classically associated with peak health and fitness.

But scientists have found that ginger hair and a pale skin offer an important advantage in the survival game.Redheads, it would seem, boast a secret genetic weapon which enables them to fight off certain debilitating and potentially deadly illnesses more efficiently than blondes or brunettes.A pale complexion permits more sunlight into the skin, where it encourages the productionof vitamin D.'Research suggests red hair and pale skin is an advantage in northern Europe because you make vitamin D in your skin, and therefore you are less likely to get rickets if you have pale skin. 'There's also good data that we need vitamin D to fight against infections like TB.This sort of thing could have a very big evolutionary impact.' The human 'ginger gene', the trait which dictates red hair, is known in scientific terms as the melanocortin-1 receptor.Even as recently as 50 years ago, before improvements in the nation's diet, many people developed rickets, a childhood disorder which causes abnormal bone formation and can lead to bowing of the bones.