It was a cold and rainy April night the first time the fires of Beltane burned.

It was 1988, Margaret Thatcher was in power, and Britain was reeling from one of the darkest points in the brutal killings and violence in Northern Ireland.

Over in Edinburgh, a small band of five dedicated individuals, followed by more than 50 curious locals, wound their way up an ancient hill in the middle of the city.

They had a meagre budget of £500, some conch shells, and wood provided by the council which amounted to one white vinyl three-piece sofa.

A desperate call to Dalmeny estate by the group's founder, who remembered childhood fireworks nights staged by Lord Roseberry - a "slightly eccentric pyromaniac" - won out.

He offered five tons of firewood, a truck and driver. The group were set.

As night fell, they dressed their May Queen in daffodils and lit their torches. A gale off the Forth and the driving rain meant it took a while for the bonfire to spark, but when it did it roared.

A piper played a slow air, the drumming began, and as the fire raged higher the music played faster.

A bottle of Grouse was cracked open and poems were read aloud, voices raised against the wind. Under thick dark skies they drummed and danced through to a watery dawn, hurling themselves through the Beltane Fire.

The season was changing and they intended to mark it, with an ancient Iron Age Celtic ritual of renewal, celebrating the end of darkness and the hope of summer to come.

Fire was seen as a purifier and healer and would have been walked around and jumped over by the members of the community in days of old.

Now entering its 30th year, the Beltane Fire Society, formed all those years ago, still burns brightly.

Set to take place on the night of April 30, there are now more than 300 voluntary collaborators who perform to a watching audience of thousands.

"It ties us back to the core nature of the seasons," explains Beltane Fire Society member Matt Richardson. "It reminds us that there is more to life."

Matt has been a part of the group for 18 years and has witnessed 19 Beltane nights, each one a dynamic reinterpretation of the age-old pagan ritual.

Atop Calton Hill, there are drummers with feathers entwined in dreadlock hair, naked figures smeared in red wielding flaming arcs and always the dancers, moving wildly before the crowds.

Once deemed controversial by churches in Edinburgh for its pagan origins, and displays of public nudity it is now a massively popular event in the cultural calendar.

In 2004, after the society was left no choice but to ticket the once free event, around 12,000 people came to watch them.

"I came to Edinburgh as a student and saw my first Beltane, and have been part of it ever since," says Matt.

"It was the otherwordliness and the sheer scale of it right in the heart of the city which drew me in.

"This magical thing happens on the hill right in front of you and it's very special."

To the Celtic people of Europe the changing pattern of the seasons was a matter of life and death.

After dark months spent indoors surviving bitter winters, Beltane - "bright fire" - was a way for communities in Scotland and Ireland to embrace the arrival of summer with the symbolic heat of fire.

In Scotland, the lighting of Beltane fires - round which cattle were driven, over which brave souls danced and leaped - would survive into modern times.

A process of slow decline, however, saw towns and villages slowly abandon the practice in the 19th century.

The last Beltane fire recorded in Helmsdale took place in 1820. In the middle years of the century the fires of Fife spluttered out, and by the 1870s they would go unlit in the Shetland Isles.

It had been close to a century since the last pagan beacons had been lit on the hilltop above Edinburgh before the original Beltane Five gathered to light them once again.

Among the original group was Angus Farquhar - then of industrial London band Test Dept, who is now part of the famous NVA arts organisation.

As he recounted to the media in recent years, that very first modern Beltane night was "wild".

"I used to drum myself into a kind of madness and then you'd look up in the morning at the watery sun rising and feel a sort of intensification of life," he told The Scotsman newspaper in 2012.

"I was more pagan then in my outlook but I still feel this incredible energy on the night and the sense performers are doing something greater than themselves."

The first May Queen was Liz Ranken, a remarkable ex-dancer with DV8 who performed the role for nine years.

On every Beltane night, it is the May Queen who leads a procession of dancers down to meet the Green Man, to signal the death of winter and birth of summer.

"Once the union has been made, the May Queen and Green Man light the bonfire," says this year's May Queen, Anna Chaney.

"For me, this is the ultimate symbol. I always like to think of it as the marriage between the earth and the sky.

"It starts from the first sparks of the neid fire and becomes the often towering inferno of the bonfire."

Descriptions of fire festivals in Edinburgh go back as far as the 16th century. It was the lower orders, the servants, who would go up Arthur's Seat.

There was whisky, drumming and dancing through to dawn, though it was frowned on by the authorities as licentious behaviour and banned.

Today, the event is viewed by most as an interactive arts performance, though for the society behind it, it remains so much more.

"We're a very strong community," says Matt. "It's changed a lot in some ways, and in others not at all. We are bigger now, a charity and more professional which we had to become, though we do still miss some of what we were in the beginning.

"But these days I think we feel more part of the festival scene in Edinburgh.

"I'd like to see it still going in another 30 years, growing within the city, always a little bit out there to keep Edinburgh on its toes."

As founder Angus Farquhar said in 2015: "I'm immensely proud of the continued flourishing of Beltane, it has always been bigger than any individual who takes part.

"We found on some small level, our common humanity and work together to release something intangibly beyond our separate lives."

For more information on the night or for tickets to attend please visit the Beltane Fire Society website.