The claim that blondes have more fun is to be put to the test by a team of scientists.

Based at the University of Edinburgh, the experts hope to discover why people have different colour hair and how it affects them.

Dermatology professor Jonathan Rees, who has already completed extensive research into red hair, said: "Curiously, for all the jokes about dumb blondes, we can hardly say anything sensible about blonde hair.

"We are very ignorant of its genetics and we don't understand why some people are blonde and others not."

Advantages

The scientists hope to discover why people's skin responds differently to sunshine depending on hair colour and what advantages there may be to having blonde hair.

Professor Rees said: "The strangest aspect of living in Northern Europe is that we get used to seeing people with different hair colours.

"We forget that for the majority of the world hair is almost uniformly black, whereas in Europe, red hair and blonde hair is quite commonplace."

Studied

Professor Rees is looking for people of all ages to help with the two-year project.

Their hair would be photographed and studied by the team who are particularly keen to find volunteers whose brothers and sisters or parents also have blonde hair.

"We are curious as to why blonde hair developed in Northern Europe and nowhere else in the world and also want to understand the way it is inherited in families," said Professor Rees.