Daydream believers

Back in December 1991, when My Bloody Valentine embarked on a British tour to promote Loveless, their 'difficult' second album and sonic masterpiece, the four-piece group were augmented by a waif-like American girl called Anna Quimby. She had been enlisted by Kevin Shields to recreate the high frequencies that he had attained in the recording studio with the aid of several guitars and a sampler. Quimby was not a guitarist, though, but a classically trained flautist.

The flute is not an instrument one usually associates with extreme noise terror, but, when My Bloody Valentine unleashed the show's crescendo, a track called 'You Made Me Realise', the instrument added an almost unbearable shrillness to what was already a blizzard of sustained sonic overload. As the tour progressed, the song became a thing of ever more terrifying beauty due to an extended white noise section that could last up to 10 minutes and was built around the repetition of a single chord played by Shields and his then girlfriend, second guitarist, Bilinda Butcher. Both had already suffered for their art, Butcher with a perforated eardrum, and Shields with the onset of tinnitus. Now, it was the audience's turn.

Such was the disorienting effect of what came to be known as the 'holocaust' section of the song that often the crowd down the front of the stage seemed to move as one into what can only be described as an altered state of consciousness, part endurance ritual, part collective delirium.

At the time of writing, it is not known whether Anna Quimby will be shuffling on to the stage of the Roundhouse in north London on Friday 20 June, when My Bloody Valentine play their first show in 16 years. What is certain is that the noise emanating from the stage will still be extreme, dangerously beautiful and utterly singular, not least because nothing that has happened in pop music since has even come close in terms of texture, sonic invention or lyrical abstraction. None the less, the group's reputation does not rest not solely on their groundbreaking music but on the often strange and erratic behaviour of Kevin Shields and the myths that have grown up around the protracted gestation of Loveless, and the equally protracted, but unsuccessful, attempt to record its follow-up .

Listening now to tracks such as 'Sometimes' and 'Loomer' from the Loveless album, you can see why Shields once said that the music he made gave off 'an attitude of uncompromising strength yet, at the same time, a fragile sense of uncertainty'. You can see, too, why Brian Eno once enthused that their single 'Soon', which actually made it into the charts, 'set a new standard for pop', describing it as 'the vaguest music ever to have been a hit'.

On Loveless, Shields forged a sound that was indeed vague but also incredibly dense, just as it was also opaque and heavy, mesmerising and, at times, overwhelming. This odd conjunction of opposites took the group way beyond the horizons hinted at on their debut album, 1988's Isn't Anything, which had become the template for an entire Eighties indie-rock sub-genre known as 'shoegazing'. It was later defined by Creation Records supremo Alan McGee as 'glorious swirls of noise with faint vocals', and its exponents were groups such as Ride, Swervedriver and Slowdive, none of whom possessed the extremity of vision of the group whose sound they borrowed and diluted.

In retrospect, My Bloody Valentine were to shoegazing what Led Zeppelin were to folk rock. Sure, they stared at the floor as they played, lost in the noise they made, and, yes, their lyrics tended towards the narcotically dreamy, just as Zeppelin occasionally came over all hippy-trippy and evoked a world of elves and ancient battles over a rattling acoustic backdrop. The noise that My Bloody Valentine created as a kind of sonic signature, though, belonged to a different and altogether more radical tradition, one that deployed dissonance, noise and texture to disorientate, then mesmerise, the listener.

One of the best illustrations of that tradition, and their otherness even within it, is the inclusion of 'Loomer' on David Toop's 1996 Ocean of Sound compilation. Amid a sea of avant-garde jazz and formal experimentation by the likes of Sun Ra, Terry Riley and Holger Czukay, 'Loomer' still sounds utterly singular, a hissing, buzzing wall of distortion over which Butcher sings her dislocated, day-dreamy lyrics. Revealingly, it is one of only three tracks that could be said to belong to the rock canon. The other two are the Beach Boys' dreamy fragment 'Fall Breaks and Back to Winter' and the Velvet Underground's still unsettlingly discordant 'I Heard Her Call My Name'. This is exactly where My Bloody Valentine, and Kevin Shields in particular, (almost) belong.

Indeed, when they first appeared in an otherwise moribund mid-Eighties indie-rock landscape, a place where the term 'shambling' was deployed non-ironically, My Bloody Valentine were often hailed by the excitable music press as the true heirs to the Velvet Underground, perhaps the most influential noise-rock outfit in pop history. On the surface, the comparison seems almost justified. Like the Velvets, My Bloody Valentine deploy repetition, ear-splitting volume and abstract visuals to unnerve the audience. Like the Velvets, too, they used classical instruments to augment, and intensify, an already visceral sound; in the Velvets case, a screeching viola, in the Valentine's, that ear-piercing flute. Both, too, were mixed gender groups who coalesced around a quiet, but controlling, male presence.

No matter which way you look at it, though, Kevin Shields is no latter-day Lou Reed. Unlike the Velvets, whose music ranged from La Monte Young-influenced avant-garde experimentation to narcotic ballads and those still strange-sounding, doomy electric madrigals intoned by Nico, My Bloody Valentine always seemed to be chasing a single overwhelmingly transcendent noise. It was a noise that only Shields could hear; a noise that, as he later admitted, echoed more clearly in his head than it ever did on stage or on record.

When Shields was asked recently what he now thought of Loveless, an album that is now 15 years old, he said: 'In my head, it feels like a half-formed version of something that could've been a lot bigger. It's like if you did something when you were completely pissed and it was actually quite a good thing and so you kind of know how you did it because you half remember, but you're never going to be there again.'

This last sentence gives a pretty good indication of how Kevin Shields speaks, which is quietly, calmly, and in long sentences that meander towards moments of illumination. The problem for journalists is that he is notoriously hard to track down. When I approached Shields though a mutual friend to ask if he would consent to a new interview, the initial signs were promising. I received a definite 'yes' within mere days and, after about a week of waiting, a text message arrived bearing Shields's mobile phone number.

The following day, a representative from Sony (who now possess the band's back catalogue) emailed to ask if I would write the sleevenotes for a very imminent My Bloody Valentine box set featuring Shields's remastered versions of Isn't Anything and Loveless, as well as all the songs that appeared on their now hard-to-find EPs and several unreleased tracks. An interview was scheduled for the following week as soon as Shields had approved the CD artwork. I am still waiting. In the meantime, the release of the box set has been postponed indefinitely.

By now, of course, Shields is as well known for his procrastination and his obsessiveness as for his music. Like one of his heroes, Brian Wilson, he seems at times to have entered the realm of rock mythology by virtue of his absence. It seems oddly ironic, then, that the first time I met him was at a Brian Wilson concert at the Royal Festival Hall in January 2002, the first of those four shows in which the damaged Beach Boy finally returned to the stage to play Pet Sounds. In conversation, Shields told me he had tickets for all four shows.

I met him again soon afterwards, again at the Festival Hall, this time for a Bert Jansch concert. A group of us went out for a meal afterwards and I talked to him at some length. In person, he does not live up to his myth, being neither tortured nor oblique, but softly spoken, articulate and, indeed, charming. You could, in fact, imagine him getting away with murder, such is his well-bred Irish-American charm, and his oddly childlike demeanour. Which, in a way, is what he did with Loveless.

My Bloody Valentine were formed in Dublin in 1984 and spent some time as exiles in Berlin before arriving in London and signing to Creation in 1988. The label was then struggling to find a group who would have the same kind of impact as the Jesus & Mary Chain, whose feedback-drenched music and narcotically inclined songs seemed to have been a formative influence on the young Shields. Likewise, the hardcore punk of Hüsker Dü and Dinosaur Jr as well as the more cerebral noise made by Swans and Sonic Youth.

On stage, the group looked almost innocuous, with Shields and his willowy girlfriend Bilinda Butcher out front on twin guitars and vocals while bassist Debbie Googe and drummer Colm O'Ciosoig anchored what was already a thunderously loud live sound. By the time Isn't Anything was released in late 1988, Shields had become the architect of the group's sound, their main songwriter and sometimes producer as well as a guitarist who was now in thrall to the sound he heard in his head. His technique involved using open tunings and keeping the tremolo arm permanently bent. The copious use of something called reverse reverb helped formulate a signature that he called with typical understatement 'glide guitar'.

'It was all simple stuff,' he said recently. 'People assumed it was all effect and studio trickery but it was just guitar.'

In his book Blissed Out: The Raptures of Rock, the music writer Simon Reynolds was more effusive, describing the sound of Isn't Anything in quasi-sexual terms: 'The guitars are rampant, clamorous, craving, grazed, engorged, honeyed, horny, somehow extremely oral, somehow obscurely irritable.'

By the time My Bloody Valentine had entered a recording studio in Southwark in February 1989 to begin work on a follow-up album, their sound had evolved even beyond that description, and Shields was convinced he could reproduce the ever-evolving textures he heard in his head in a matter of weeks. It took him almost three years.

The making of Loveless is shrouded in myth, misinformation and conjecture. It was recorded in a reputed 18 different locations, and attended by at least that many engineers, Shields's bouts of creativity punctuated by ever-increasing periods of lethargy and disillusionment. At one point, his obsessiveness, and the increasingly long hours he toiled and fretted in the studio without sleep, seems to have precipitated a bout of mental illness and a long period of self-enforced seclusion. Interviews done with the group at that time suggest they were existing in various degrees of deprivation in London squat land. It was during this time that Alan McGee claims he went to visit Shields in his house-cum-studio in Streatham, and found a reclusive-to-the-point-of-paranoid figure whose abode was ringed with barbed wire and overrun with chinchillas. Shields has subsequently claimed that the barbed wire was there only to deter intruders from stealing his equipment, but admitted that for a while he 'totally lost it'.

So, too, did McGee and his fellow director, Dick Green, who are said to have funded Shields's quest for perfectionism to the tune of £250,000, thereby causing the slow drift of Creation Records into bankruptcy. In David Cavanagh's exhaustive history of the label, My Magpie Eyes Are Hungry for the Prize, Shields's talent for procrastination is also blamed for precipitating Green's nervous breakdown as well as McGee's now infamous mental and physical collapse when he was stretchered off a plane in Los Angeles by paramedics. A few days later, the paramedics were summoned to the Mondrian Hotel on Sunset and found McGee in such a hyper state that they feared he would not make it to the hospital. He was diagnosed with acute nervous exhaustion.

'There's a huge myth that's grown up around Loveless and around Kevin's so-called obsessiveness,' says Bobby Gillespie, the lead singer of Primal Scream, who were also signed to Creation, and making their acclaimed album, Screamadelica, around the same time. 'But the truth is that Creation were always short of money before Oasis came along. It was a case of them continually having to rob Peter to pay Paul. I doubt the label ever had three hundred grand to spend on Loveless. Even though it seemed to take forever, it probably cost the same as Screamadelica, which was about a hundred grand.'

Dick Green, who now runs the label Wichita, and who was caught in the battle of wills between Shields and McGee at Creation, begs to differ.

'Loveless costs a lot more than a hundred grand. A lot more! There were studios and tape and engineers and equipment, taxis and food (lots of food, I seem to recall) and the studios were not cheap by our standards. Also, Kevin always checked them out usually before he went in, and, in some cases, he actually suggested them. But then there was always something wrong that meant they had to move, and the move was always an upheaval, all that taking down and setting up again and trying to find space in studios at short notice. Most of the time, too, it seemed no progress was being made.'

The issues underlying the epic bouts of procrastination on Shields's part were almost certainly linked to Shields's slacker lifestyle at the time, his well documented tendency to sleep the days away and function at a snail's pace nocturnally. The weight of expectation that now surrounded this epic work-in-progress increased with every day that passed in inactivity. Having since worked with Shields, who became one of Primal Scream's occasional floating members for a while, playing on and mixing several tracks on both their XTRMNTR and Evil Heat albums, Gillespie describes him as both 'a true visionary' and a much misunderstood character.

'If you get to know Kevin,' he says, 'you realise that he's a guy who is intensely involved in whatever he is doing, but he moves to his own rhythm. He's also nocturnal by nature and you have to take that on board and work with it. I honestly think that what was driving him up the wall when he was trying to finish Loveless was the sheer frustration of the situation he was trapped in. Cheap studios, unsympathetic engineers, loads of time being wasted putting right things that had gone wrong. He also had some personal stuff going down,' Gillespie adds, mysteriously. 'He once told me the record was called Loveless because it was made during the most loveless time in his life.'

These, one suspects, are not opinions shared by McGee or, indeed, the ever-patient Green, whose hair went grey overnight during the final fraught few weeks before Loveless was finally delivered to Creation. And that was before the editing and mixing stage, when Shields, true to form, detected a glitch in the overall sound, and actually suggested that the entire album should be recorded all over again from scratch. By then, McGee had been forced to borrow £22,000 off his father in order to pay one of several recording studios who were threatening to withhold tapes until all outstanding debts were settled. 'My dad's a panel-beater; he's not a businessman or anything like that,' he told David Cavanagh. 'And I'll tell you what really got to me. It was the insurance money he had got from my mum's death. I borrowed it to finish a record.'

When Alan McGee was approached for his side of the Loveless story, he declined a new interview. Green was more forthcoming. 'The battle between Shields and McGee was a battle of two extremely strong wills and personalities, sometimes in tune and very often clashing. I certainly don't think Loveless was the only cause of the troubles at Creation. It was an ongoing struggle for survival financially, constantly pushing for what we could and couldn't achieve, waiting for that golden egg always just beyond reach at that point. I think My Bloody Valentine did become the focus of all the tension because the recording was just going on and on with no end in sight.'

For his part, Shields has been uncharacteristically bullish in one of his rare recent interviews. 'The two things we're really known for are spending Creation's money and making records with loads of overdubs on them,' he said. 'The exact truth is this: about a month before we started Loveless, Creation pulled away from Rough Trade distribution and said: "Our contract is up with you. We don't want to sign again." By the time we resumed recording in September of '89, Creation was already bankrupt. When we first started Loveless, no one signed to Creation. When we finished the damn record, they had hit records and bands on Top of the Pops. They were a very successful label. All that stuff about us nearly breaking Creation because we spent all their money is literally 100 per cent lies.'

He concluded the same interview by saying, 'I do sound like I'm being pretty negative about the whole Creation thing, but it's more that I just get bored when people ask me. I'm just going to tell the truth now. I always used to gloss over it, but I'm bored of glossing over the truth.'

The big question of course is whither My Bloody Valentine now? Shields has intimated that the forthcoming gigs may be a way of easing the group back into the recording studio to attempt another album. He said recently, 'We are 100 per cent going to make another My Bloody Valentine record unless we die or something.' No date was set for the recording sessions, though, and Island Records may have something to say about the project given that they reputedly sank £500,000 into the recording of a third My Bloody Valentine album, which was eventually aborted when, as Shields later put it, 'we lost the plot majorly'.

Dick Green still 'likes Kevin a lot', but says, 'There was always a touch of madness in his methods and I think the fact that he has not really finished any new music in so long means that there is an issue. But certainly in the last few years he has seemed happy.'

For all the uncertainty that surrounds their future, any activity by My Bloody Valentine is good news indeed for the group's legion of long-suffering fans who have had to make do in the last 16 years with glimpses of Kevin Shields's interrupted but still ongoing work-in-progress via remixes, side projects and soundtracks. The next record to bear his imprint will almost certainly be a recording of The Coral Sea, a collaboration with Patti Smith, which was unveiled in a live improvisation during the Meltdown festival that she curated at the South Bank in London in 2005.

'It's a long poem that I did in memory of Robert Mapplethorpe,' she says. 'I met Kevin when I was doing Meltdown and he agreed to do it. I didn't know anything about him - I didn't even know what he looked like - but when we met I knew that we would be friends... There was an immediate connection and trust, because in order to do what we did - improvise for over an hour without rehearsals - there has to be trust.'

Smith, who will be flying into London to attend the forthcoming My Bloody Valentine shows at the Roundhouse, describes Shields as 'highly intelligent, very abstract and utterly unique... he has a moral sense and a revolutionary sense. He's kind and he's fierce. I don't have anything negative to say about the man or the music.'

And that, for all the mystery that surrounds the quiet man of noise-rock, echoes what many of his fans and fellow musicians think. The worst thing you could say about Kevin Shields, in fact, is that he considers time to be an infinitely elastic concept. 'I suppose,' he mused recently, 'I've been more wrong than most people when it comes to time in the sense that I'm always late. But it kind of works. That's the weird part of it... everything works out in the end. I'm kind of happy.'

Had I spoken again to Kevin Shields, I was planning to read him a quote from another interview I did a few years back with the psychologist and author Adam Phillips. When I asked Phillips what would be the single thing that might make us more content in our ever-accelerating culture, he took his time before replying. Then, finally, he said: 'We need to find the time to daydream and be bored, and to see that, too, as a part of our creativity. We need, as it were, to find the time to waste time without worrying about the consequences.' Kevin Shields, you imagine, would have approved.

· My Bloody Valentine play the Roundhouse, London NW1, Fri 20 to Tue 24 June; Apollo, Manchester, Sat 28 & Sun 29 June; Barrowlands, Glasgow, Wed 2 & Thu 3 July; and Bestival, Isle of Wight, Friday 5 September. For European tour dates, see mybloodyvalentine.co.uk

My Bloody Valentine: The essential cuts

You Made Me Realise  (1988)

MBV's four-track debut for Creation may have introduced shoegazing to the world, but its unearthly fusion of innocence and venom was far removed from the meanderings of its toothless copyists.

Isn't Anything (1988)

While its successor, Loveless, crops up in more greatest album polls, Isn't Anything is, arguably, the superior set, not least because it is less inclined to hide its gorgeous tunes ('You Never Should', 'Nothing Much to Lose') beneath disorienting layers of feedback.

Loveless (1991)

Recorded over a two-year period, Loveless is rumoured to have cost £250,000 to make and as such to have all but bankrupted Creation, destroying Shields's relationship with label boss Alan McGee. However, thanks to its spirit of adventure and sonic otherness, Loveless was, and remains, one of the most influential albums of its age.

Lost In Translation (2003)

At a time when practically everyone had given up on Shields, he was brought back to centre stage by Sofia Coppola, for whom he made his first new tracks in a decade. All were good, but 'City Girl' and 'Goodbye' were especially fine, if markedly less spiky than Shields's work with MBV.

Paul Mardles

After Loveless: Those other 'lost' albums

The Beach Boys Smile (1966)

The intended follow-up to Pet Sounds, and a work dubbed by Brian Wilson as 'a teenage symphony to God', Smile is one of the most talked about non-releases of all time. Featuring complex wordplay and revolutionary production techniques, a version was finally released in 2004, but after all that happened even Wilson couldn't recall how it was first meant to sound.

Neil Young Homegrown (1975)

This largely acoustic album, on which Young documented the fallout from his relationship with the actress Carrie Snodgress, came so close to being granted a release date that a cover was prepared featuring him with a pipe. Famously, however, Young chose to release Tonight's the Night instead after listening to both albums on the same reel.

David Bowie Toy (2001)

Prompted by his 1999 and 2000 tours on which he performed songs from his early days, Bowie made noises about fashioning an album of some of these tracks. However Virgin pooh-poohed the notion and Toy never saw the light of day.

Prince Various

No one, surely, has recorded more unreleased albums than the Purple One. In 1986 alone he made Dream Factory and Camille, on which Prince's voice was tampered with to make it sound like a woman's. Among the others that got away are The Dawn (1997), High (2000), and Madrid 2 Chicago (2001).

Guns N' Roses Chinese Democracy

'It's a very complex record,' Axl Rose said in 2000. 'I'm trying to do something different.' It will have to be very, very different in order to justify the 14 years the band have spent in the studio, not to mention the $13m bill. If, as rumoured, Chinese Democracy is released this year (and OMM confidently predicted it would come out in 2007), it will be partly thanks to Dr Pepper, which vowed to give a drink to every American if the album makes it to the shops.

Paul Mardles/Peter Kimpton

· What would you say is the greatest unreleased album? Let us know at http://blogs.guardian.co.uk/music