The National Review of Live Art is 30 years young and celebrating by inviting back over 100 of its top alumni

It was in the 1980s and the festival crowd – performance artists covered in piercings, audience members fed on an intensive diet of the most avant-garde live art in the world – were holed up in the Glasgow Central Hotel. As were, it turned out, the members of a Star Trek convention.

"It's an image that stays with me vividly," Etchells recalls with a laugh. "The hotel seemed to be occupied entirely by artists in black with tattoos or Klingons with phasers at their hips. It certainly made for an interesting mix at the bar."

Late at night in the hotel corridors, as dancers sauntered past delegates dressed as Spock, the rumble of trains providing a soundtrack to this unexpected collision of art and life, Etchells understood the importance of the NRLA. It was a breeding ground, a place for bringing together theatre, art, dance, and visual art that no longer fitted into those categories, and a home for artists like him. Decades on, it's still all those things.

"It was the blurring between art and life that struck you immediately," he continues. "Suddenly you realised that what you were doing made sense alongside a bunch of stuff that other people in the world were doing. It was a feeling of community and of being pushed into encounters with work you might not have considered."

Or, as another returning artist to the NRLA puts it: "Welcome to Bedlam".

The NRLA is 30 years young this week, and it's showing no signs of maturing or settling down. In the past three decades it has hosted work from some of the most adventurous artists around, people from all over the world working, as one of them puts it to me, "at the coalface of the cutting edge".

The NRLA has travelled to Nottingham and London, but has always returned to roost in Glasgow. It has featured performances that have lasted moments and others that have gone on for 97 hours. Audiences have watched paper launched into the Glasgow night sky on helium balloons, been soaked by upturned hoses, and had their hands washed with soap made from the fat of an artist's stomach. The NRLA has hosted artists who have screamed, wept, writhed, slept, and drawn blood. To celebrate its long and, you might say, colourful history more than a hundred of them have been invited back, Etchells among them, to present new work. The line-up is nothing short of extraordinary, including work from such live art luminaries as Ron Athey, Neil Bartlett, Julia Bardsley, Alastair MacLennan, La Ribot, Lee Wen and Kira O'Reilly. That it's called the National Review of Live Art is laughable. There aren't many festivals this international.

Ian Smith, best known for his Glasgow street theatre company Mischief La-Bas, has the job of taming the beast, or rather unleashing it. This will be his 14th year as master of ceremonies.

He recalls perching on top of a wardrobe some 20 years ago with Nikki Millican, who runs the NRLA, Neil Butler, now director of Glasgow based UZ events, and the late and hugely influential experimental artist Paul Burwell. "None of us can remember what we were doing on top of that wardrobe but we all think of it as a moment, indicative of the kind of behaviour that always goes on at the NRLA," he says. "I've seen people dressed as fish, bleeding, dancing, singing, over the last 30 years. It's a total immersion in their interior minds. You won't get that anywhere else." For NRLA virgins he recommends buying a day pass, diving in with your mouth open, and "not worrying about not liking the taste of it all".

What is he most looking forward to in this year's vast programme? "There is a guy called Zoran Todorovic who is doing something on liposuction and will be turning it into jelly snacks for audiences," he says. "I'm very keen to see Ian Hinchliffe who resembles Worzel Gummidge and is one of the most exciting loose cannons I've encountered. He was the first performance artist I saw when I was 20 and I just couldn't believe there were grown men out there who had got that far in life being mad poets."

Alastair MacLennan, who studied fine art at Dundee's Duncan of Jordanstone college in the 1960s, could be dubbed one such mad poet. Now 67, he is renowned for his marathon-like durational performances, lasting up to 100 hours. For Etchells, whose company made its first durational work for the NRLA in the 1980s, MacLennan was a huge influence. "I first saw him at the NRLA in the Third Eye Centre," he recalls of the venue that has since become the CCA. "It was a 72-hour performance and the depth and slowness of that work was hugely important to me. Sometimes he would be in silence, in some weird mode with a shopping trolley full of sheep's heads, or chatting to people about what he was doing. It was astonishing." This year Forced Entertainment will be presenting Void Story at the Tramway, which takes the form of a slideshow accompanied by performers who dub the images live, using mics and laptops.

Over in the newly refurbished Arches, MacLennan will be presenting a shorter work called Ink Ash, just five hours long this time. "It will be rhythmic, ritualistic, and the intensity will build over hours," he explains. "What Nikki (Millican] started at the NRLA was something sensual and radical and it has continued in that way. It was possible to do long performances at the NRLA, which was awkward elsewhere. You could live in the spaces.

"At that time I was younger and interested in exploring the body as a piece of elastic, seeing how far it could go. I wanted to break all my normal daily patterns of eating and sleeping. The NRLA has been so important for my work. It's about people going to the limits of their disciplines, and then going beyond them. I think it's the longest running continuous festival of live art in the world and I have a great respect for Nikki's dogged perseverance."

All the artists I speak to describe the significance of the NRLA as a home, sometimes the only one, for their work. Julia Bardsley, who left behind a hugely successful career as a theatre director to pursue more experimental work as an artist, will show Aftermaths, the final part of her trilogy on the Book of Revelations at Tramway this year. Both of the other parts have also been at the NRLA in past years. She describes Aftermaths, tongue only partially in cheek, as an optimistic take on the apocalypse and is inviting audiences to wear black and bring something (also black) they don't mind parting with to the show.

"This work is difficult because it doesn't really fit in anywhere," she explains. "It's not straight theatre but it's not hardcore live art. It's sit somewhere in the middle and that means there are very few contexts for it. The NRLA is one of them. The festival has presented all three pieces, invested commissioning money, and if we hadn't shown there, we wouldn't have got other gigs afterwards."

For Smith, who claims the piece that most sticks in his mind was watching a woman stitched into a sheath dress of stinking Scottish salmon fish scales, the NRLA is not about a bunch of live art luvvies congratulating – or indeed out-shocking – one another.

"We're all hardcore strangelings," he says. "Let's get that straight. But the stuff people see here will be filtering into the mainstream in five years. Any car advert with gold-painted bodies has come from some body artist opening their veins or covering themselves in feathers. Lady Gaga comes straight out of Warhol's Factory. The NRLA is one of the few moments in the year when we feel we're right and everyone else is wrong."

He laughs. "We do contribute to society, you know… eventually."

The 30th National Review of Live Art runs from today until Sunday at the Arches, Tramway and CCA in Glasgow. For a full programme, visit www.newmoves.co.uk/national-review-of-live-art