Does dancing in a circle, decked out in ancient garb, in the dead of night, while banging a tambourine, constitute a crime? This is the question many of the big-beards in the Greek Orthodox Church have been forced to ask as the realisation has dawned that Apollo-loving pagans are among us again.

If the black-shrouded paragons of resolutely Christian Greece thought they could keep the believers of ancient polytheism at bay, they have had to think again. Last week, like a thunderbolt from Zeus himself, an unexpectedly large horde of pre-Christian devotees descended on Mount Olympus for the annual Prometheus festival. Many wore white robes although a minority, it is true, came wearing little more than their love for the 12 ancient gods. But a bit of near-nudity notwithstanding, their arrival might have gone unnoticed had it not been for the fact that there were 4,000 of them dancing in the wood-encircled meadow halfway up the mountainside.

Even worse, for Greeks who take their church and nationalism very seriously, a large number came from distinctly foreign fields. And as the pagans from Canada, the UK and Europe heartily sang ancient Orphic hymns, dedicated to the glorification of the summer solstice, the sound rippled all the way to pagan-hating Athens.

Greek identity is very much part and parcel of Greek Orthodoxy, and few things get under the pillar hat of a Greek Orthodox priest more than these sort of heretics. They take threats to their religion very seriously. Since the Byzantine empire, priests have reserved especial scorn for those who want to resuscitate the idols of a degenerate dead religion. Apollo, Zeus, Hermes and Athena might add to Greece's allure for tourists but, so the logic goes, when taken more seriously than their plaster models they are positively dangerous.

'What their worshippers symbolise, and clearly want, is a return to the monstrous dark delusions of the past,' hissed Father Eustathios Kollas who presides over the community of Greek priests. 'They should be stopped.' But that may be easier said than done. There could be as many as 60,000 practising pagans in a country that still imprisons those who proselytise.

This year, despite fierce protests from the Orthodox Church, pagans were allowed to set up a cultural association. Now they want to take their battle to the ancient temples of Greece in the hopes of one day having the religion officially recognised.

'We want to conduct our rituals there,' says James O'Dell who flew in from Croydon, south London, for the Olympian festival. 'Our religion may sound strange but we're actually quite boring and normal, apart from this.'