It is 10.30am on a sunny Saturday morning and in a darkened vault below Glasgow Central station, out of view of the unsuspecting shoppers above, two men and three women in flowing cloaks and dresses of black, white, and green take to the stage carrying elaborately carved staffs and a huge animal horn.

After sipping mead from the horn and invoking the gods of the earth, moon, sun and the waves, an audience of several hundred people join them chanting: “Hail Clutha! Hail Clutha! Hail Clutha!” Holding it aloft, a former doctor — a hulking bearded man known as DC — implores the crowd to “enjoy your day and honour your gods as you do so”. You half expect a flash of lighting to strike the stage, but instead the motley group of druids, wiccans, heathens and pagans traipse quietly off and head for the River Clyde to cast away the mead. (In case you are wondering, Clutha is the goddess of the Clyde Valley, and the mead is a sacrifice. Obviously.) So begins Witchfest Scotland, the country’s biggest festival of witchcraft, sorcery, magic and all manner of new age mystery. In its fourth year, this extraordinary convocation has drawn together 600 fans of the occult from across the UK and beyond to gather in The Arches, on Argyle Street.

Over the course of the next few hours, I am told in a matter-of-fact way how some cast spells that change the weather, while others have seen ancient Norse gods walking into their rooms or made contact with the dead.

And amid the incantations and spell-making, it’s plain that these people really do believe in fairies. At one point on the main stage, Alicen and Neil Geddes-Ward are joined by a primary school-aged girl in a purple velvet dress and a little boy wearing a black cloak and starry-pointed wizard’s hat.

Alicen urges the audience to use their energy to “bring the fairies into the circle”. Soon the crowd are murmuring: “I believe in fairies, I do, I do.” Alicen seems pleased. “I hope you can feel the energy has changed, it has lifted,” she says. “We’ll symbolically go through the arch and enter fairyland.”

When the excitement has died down, I set out to meet some of the crowd who have come to share spells and gaze into crystal balls together. They turn out to be a disarmingly friendly bunch.

DC lives on the south side of Glasgow and is a well-known face to those who attend the half dozen “moots”, or informal groups of pagans, that meet across the city. The 46-year-old former doctor worked in hospitals in Birmingham and Glasgow, but no longer practises after contracting ME.

He tells me he believes in ancient Norse gods. His staff is carved with the words “Thor make this holy” and he wears an obscure symbol of three triangles called a Valknut, sacred to the god Odin, who, he says, once appeared to him.

“I saw him in his traditional dress — grey cloak, carrying a spear, with a blue hat and one eye,” he says. “I was writing an e-mail, wasn’t clear about something and said I needed answers. This person turned up and answered my questions.”

Elaine Hindle, a kindly looking middle-aged lady who works in a canteen in Paisley, was drawn to Druidism four years ago after falling ill. “Magic is something that is there,” says Hindle, who is dressed in a green crushed-velvet gown, and is holding a staff with a black feather attached.

“It’s a matter of using intent to change the energy for the benefit of someone else.”

Hindle, however, is reluctant to tell her work colleagues about her spiritual beliefs in case she gets ridiculed. Not so Martine McFarlane, 34, an IT specialist at Glasgow Caledonian University, who is open about her beliefs.

“I am definitely a witch,” she says. “Catholicism didn’t do it for me, but paganism did. I just fell into it a few years ago. My family joke about it, but they are quite accepting.” Giggling, she admits she likes the “girlie” part about dressing up.

Her friend Caroline Shearman, 20, a Glasgow University zoology graduate, comes from a Church of Scotland background, but declared herself an atheist when she was nine. The former president of Glasgow University Pagan Society says she has had contact from her oldest brother, who died several years ago. “It feels like electricity, a very strong emotional feeling,” she says. “The first time I found out it was my brother, you could almost make out a silhouette of him.”

Nobody knows how many witches there are in Scotland, but the 2001 census found 24,050 people have religions other than Christian, Buddhist, Hindu, Jewish, Muslim or Sikh. These included 1,930 pagans, made up of a variety of beliefs, such as Wiccan,Pantheist, Druidism, Animism, Shamanism, Pagan Spiritual and Celtic Pagan.

Pauline Reid, the Scottish organiser of Witchfest, says the success of the Harry Potter films have made witchcraft more acceptable. “People are looking for something the church doesn’t do for them,” she says. “It is stuck in the past, whereas Wiccanism is a growing religion that changes.”

Reid, 34, who runs a beauty and holistic therapy shop on the south side of Glasgow, describes herself as a Wiccan priestess. She runs a coven that meets in caves and the woods around Ayrshire. All she will reveal about the rituals is that they involve three degrees: initiation; learning how to cast a spell; and becoming a high priestess.

Reid, who also runs a monthly moot for 40 people in Samuel Dow’s pub in Pollokshields, insists there is no such thing as black and white magic. “You have the ability to curse or cure, and it is up to you how you use it,” she says. “I do quite a lot of fertility spells. A lot of people I’ve done spells for were on IVF treatment for years and now have children.”

“Spells are like prayers,” she adds. “It is the intent that causes the spell, causing change at will but using the elements and the planetary aspects as well.”

As I’m about to make my excuses, DC says with a hearty laugh: “All that black stuff about Harry Potter? We’re not like that at all — we’re all very cuddly.”

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