For more than a thousand years, they have allowed only men to enter their ancient stone monasteries.

But the monks of Mt Athos in Greece now fear that the peace and quiet of their all-male sanctuary is at risk from a new law that allows people to change their gender.

The law, which was passed last week by the parliament in Athens, allows Greeks over the age of 15 to change the gender listed on their identity cards through a simplified court ruling, without proving they have undergone sex-change surgery.

The Orthodox monks fear that the law will enable women to simply declare themselves men in order to earn the right to access the jealously-guarded peninsula in northern Greece.

The rugged peninsula is home to 20 monasteries and more than 2,000 monks, some of whom shun the relative comfort of dormitories and refectories to seek even greater isolation in tiny shacks bolted to vertical cliffs.