"We are moving into a new time," says the leader, brandishing a huge set of antlers. "We are becoming more accepted. Paganism is reasserting itself." Paganism is casting its spell over more people now than ever before in the modern age. There are said to be a quarter of a million practising pagans in this country, double the number of a decade ago.

That would make them more numerous than Buddhists (of which there are 144,500, according to the 2001 census) and almost as numerous as Jews (259,000) - and it doesn't even allow for the growing tribe of unofficial, instinctive pagans such as my friend Cath, who planned to celebrate the summer solstice in the early hours yesterday by "going out into the garden at dawn and just tuning in". At Stonehenge at least 30,000 people were expected to watch the sun rise in the company of the druids who see themselves as practising the ancient faith of pre-Christian Britain. For them, the sun is symbolic of one aspect of the "universal force which flows through the world and which can be encouraged to flow through us", according to Philip Carr-Gomm, founder of the Order of Bards, Ovates and Druids and author of the new Book of English Magic. The druids are only a small part of modern paganism, which encompasses a bewildering number of traditions or "paths", but central to them all is this idea of a divine force inherent in nature. It is an individualistic faith that encourages each person to respond in their own way, so you don't have to be a druid, or belong to any kind of order at all.

"Everyone's a pagan now." Not quite, maybe, but the rise has been dramatic. The census in 2001 recorded 40,000 pagans, but the true figure may be higher. "Pagans don't like telling the government what they're up to," says Ellis.

The Pagan Federation's membership list includes druids as well as wiccans, practising modern witchcraft; shamans, engaging with the spirits of the land; and heathens, worshipping the gods of the north European tribes (including Thor). But then there are the neopagans such as Bantu, always visible at environmental protests, who wouldn't think of belonging to any kind of federation and who pursue a rainbow of revived, recreated or invented beliefs with nature at their heart.

All you have to believe to be a pagan, according to the federation, is that each of us has the right to follow our own path (as long as it harms no-one else); that the higher power (or powers) exists; and that nature is to be venerated. If you asked everyone in Britain if they agreed with those three statements, millions would put their hands up. At its loosest, paganism is beginning to look like our new national faith.