Forensic scientists have developed a technique which should allow police and immigration officials to find out where a person has been living for the last few months or years – by analysing residues in their hair.

Recent research has revealed that hair, as well as urine and saliva, contains information about what food and drink a person has consumed – and where that food came from.

This should allow police to devise a simple, inexpensive test to find out which region of which country a person has been living in.

The technique, which involves scanning microscopic residues from food and drink, could also be used for checking alibis of people in Britain suspected of serious crimes such as murder, rape and child abuse.

Dr Stuart Black, a forensic specialist at Reading University, said yesterday: “If someone says I want to claim political asylum and claims to be from Kosovo, but in fact is from somewhere else, we will be able to find out by looking at their hair and tracing their movements.

“We should also be able to find out where someone like a murderer has lived for most of their life.”

The key to the technology is analysis of the “atomic signature” of water residues in hair, urine, saliva or other tissue.

In any particular region in Britain, Europe and elsewhere, the precise arrangement of hydrogen and oxygen atoms, or isotopes, in water is unique.

More here.