The ancient stones were unearthed under a gateway leading from a ruined medieval church to the adjoining manse in the village of Temple, Midlothian. One, believed to be of 10th-century origin, is marked with a simple early Christian cross. The second appears to be from a later era and is decorated in a much more puzzling style.
Possibly carved for a knight, it features a braided cross, a sword and a shield, which is marked with strange shapes in the style of “Pac-Man”. Wary locals note that the markings bear a striking resemblance to the characters in the 1970s arcade game and fear that they may lead to UFO enthusiasts arriving in the village en masse.
The location of the stones lends the discovery a further piquancy. Seven miles (11 kilometres) away lies Rosslyn Chapel, the astonishingly ornate church made famous in Mr Brown’s thriller The Da Vinci Code. Legend has it that the Holy Grail is hidden in its secret vaults.