"When we launched Throbbing Gristle at the ICA in 1976,” explains the multi-instrumentalist Cosey Fanni Tutti, “it was about breaking down all preconceived notions of what popular music should be and how sound could communicate things to people in an enjoyable way. We were taking music and painting with it.”

This is probably the first time that a live show by Throbbing Gristle – one of the most forbidding musical experiences of the 1970s – has been described as “enjoyable”. “Character building” would be a more appropriate description of the group’s churning, punitive noise and sociopathic songs. Barely technically competent, they played on instruments modified, and in some cases custom-built, by the electronics whizz Chris Carter. They were provocateurs whose aim was to strip away all layers of artifice and get to the true self – by any means necessary. Since the group split in 1981, its “mission complete”, Cosey, Carter, Genesis POrridge, and Peter Christopherson have all remained active in music in a myriad of projects, including Psychic TV and Coil. Back together since 2003, Throbbing Gristle have just released their first new album in 26 years, Part Two – The Endless Not. Although dark and characteristically intense, their music is much more sophisticated now – enjoyable, even.

In April the group broke new ground when they played at the Donau Festival, near Vienna, with a 20-strong choir. Their next performance is in the Turbine Hall of Tate Modern, where they will accompany early Super 8 films by Derek Jarman ( see feature, page 14) in the Long Weekend festival.

“It seems to us now,” says Christopherson on their reasons for reforming, “that the record business is in as bad a situation as it was in the 1970s, if not worse. It’s not really able to make a statement unless it’s directly related to putting cute boys and cute girls onstage. We felt it was important that our message could be heard again, and people could realise that music can mean something.”

Cosey is surprised at how easily the group slipped back into working together. “It was no problem at all, because we still have a shared view of what sound we want to create together. All gloves are off and anything goes, so you don’t have to think about it, because there are no rules.”

Throbbing Gristle (Yorkshire slang for an erection) formed out of COUM Transmissions, a notorious performance group started by POrridge and Cosey. Their last show, Prostitution, included a display of photographs from Cosey’s stints as a model for top-shelf magazines and a display case of used tampons. Tory MPs were predictably enraged – Sir Nicholas Fairbairn called them “wreckers of civilisation”.

The group’s label, Industrial Records, may have given the name to a whole musical genre in the 1970s but the band’s concept of “industrial music for industrial people” was far from the “leather clothes, metal bashing and distorted sounds” that Christopherson feels typify today’s industrial music. It was more a symptom of the mid1970s, when Britain’s traditional industries were slipping into decline against a background of trade union unrest. At this time the group rehearsed and recorded in a disused industrial building in Hackney, where the noise of the city and the sounds of manufacturing processes all subliminally fed into their music.

Though they kept apart from their peers, they operated within the rock world – not renowned as a medium for disseminating views of subtlety or ambiguity. With hindsight, the group’s use of images of Auschwitz in their artwork, and POrridge whining his way through lyrics that referred to gas chambers and the Moors Murderers, seem like a sick joke dressed up as journalism.

“Back then, and even today, the only thing that really matters is if we are interested in it,” Christopherson counters. “Our intention was never to shock. It was quite the reverse. What was important was that we were examining difficult subjects, because they were interesting to us, in this weird activity of playing live with TG.”

If not totally convincing, these justifications certainly appear sincere, and in conversation the group are articulate and disarmingly affable. They aren’t the sort of people you would pick out in a crowd, with the notable exception of Genesis Breyer POrridge – as he is now known – who is engaged in the utterly extraordinary process of “pan-drogyny” with his partner Lady Jaye. In what they see as a blow against divisive notions of self, they are trying to become one entity. They have undergone extensive cosmetic surgery in order to resemble each other more closely. In his case that means cheek and breast implants, and a trout pout.

Christopherson became a high-profile music video director in the 1980s, working with The The and Barry Gibb. He is particularly enthusiastic about providing a Jarman soundtrack. He explains how Jarman would project two Super 8 films on to the wall of his flat and film the resultant superimposition. “I think people forget how much influence he had on the culture of the 1970s and 1980s.”

Is there a fear that the new Gristle is merely a diluted version of the old band? Their early work does cast a long shadow. “I didn’t stand in that shadow myself,” muses Christopherson. “I wasn’t particularly impressed. I thought they were good records, but the next project is always the most exciting one for me.”

Throbbing Gristle/Derek Jarman, Tate Modern, London SE1 (www.tate.org.uk 020-7887 8008), May 26, 9pm (returns only)

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