The most visible British genetic marker is red hair, he added. The writer Tacitus noted the Romans' surprise at how common it was when they arrived 2,000 years ago.

"It's something that foreign observers have often commented on," Miles said. "Recent studies have shown that there is more red hair in Scotland and Wales than anywhere else in the world. It's a mutation that probably occurred between 8,000 and 10,000 years ago."

Hooray for being a mutant!