Five years is an age in the world of popular music - entire careers will come and go - but for The Blue Nile it is merely the time that has passed between the release of their stunning 1984 debut album, A Walk Across The Rooftops, and the appearance of their second, Hats. For those who haven't heard it, The Blue Nile's music really is impossible to adequately describe or categorise. Comparisons are useless. For the record, I will just mention that they've been described as sounding like Tom Waits, The Yellow Magic Orchestra, Talking Heads, Pink Floyd, Peter Skellern... which, of course, tells you absolutely nothing. I can only say that their music is the purest distillation of emotion into a musical form that I know, and that its emotional power is all the greater for the lack of association with a familiar genre - which is a problem with even the finest soul or pop. A handful of adjectives can suggest something about the music - shimmering, evocative, atmospheric, intoxicating, mesmeric - but you have to experience it for yourself. The men behind the music are the Glaswegian trio of Paul Buchanan, Paul Joseph Moore and Robert Bell, and five years after I first fell under the spell of their music. I'm sitting in a flat in North London asking them why it took so long to get around to recording a second album.

"Get around to it is about the right phrase," says Paul Buchanan, who does most of the talking. "We always intended to do it, and were working towards it, but for one reason or another - many of them strictly practical - that amount of time passed. One year passed recovering from and coping with the attention, dealing with administrative details, and so on. Then we started working for a little bit, and of course we were already late by record company schedules, so we were under some pressure, and in some ways that made the music harder in coming. Then we couldn't get into the studio for a year because another band was in there, so it just added up."

After these delays, the band actually spent around two years in Glasgow's Castlesound working on Hats, an album every bit as good as A Walk Across The Rooftops. The sparse, shimmering arrangements and Paul Buchanan's voice evoke a mood more powerful than anything I can think of, and in the midst of this, images and moments are conjured up with crystal clarity and quiet intensity - falling in love, loneliness, moments of self-doubt and optimism. If the two albums sound fairly similar, then this is less because the band are repeating themselves than because they simply sound like no-one else; The Blue Nile have a direction of their own, as their astonishingly mature debut album made clear. Buchanan is modest in his assessment of The Blue Nile's skill at creating such evocative music.

"I don't think we try and invent that, but if you're aware that the music can be like that, then for us we'd like it to be like that. So if we don't get it we won't put a record out, and if we do get it we will put a record out. Achieving what you just described is what fulfills us, but you can't set out with that intention.

"We have snapshots in our heads and we don't particularly know where they come from, and our job is to make music that truly represents those snapshots, and not intervene by putting in our designs or making it a vehicle to show off or make money for us. Therefore, I think that we just do whatever pertains in our imagination to the visual image, or the emotions that you mention."

MUSICAL FREEDOM

The three band members profess to having "no set roles in the studio", and simply play whatever is necessary to achieve the effect they want at the time. As a rule, Paul Buchanan sings and plays guitar, Robert Bell plays bass and Paul Moore plays keyboards, although these are more guides to who probably played what than anything more definite.

Robert Bell: "...it doesn't mean that if you hear a bass on the record, that it's me playing bass or whatever. Everyone can do whatever they want."

This freedom is possible because The Blue Nile's music depends more on the careful assembly of simple elements than one or two virtuoso parts. Paul Buchanan puts it like this.

"What you have to appreciate is that a lot of the parts in our music aren't complicated. That's not an issue in itself, but that seems to help us in forming the picture. That's the way it comes out."

Additional musical contributions on both albums came from the string section of the Scottish National Orchestra, and Castlesound engineer Calum Malcolm, who played extra keyboards. Classical percussionist Nigel Thomas also worked on A Walk Across The Rooftops, but being unavailable for Hats, the band took over his role. The 'song' and the 'production' seem indivisible in The Blue Nile's music - it's very hard to imagine one without the other - so how did the songs on Hats get written?

"Well, there's two ideas in there. One is that we share things between the three of us - it's just sort of intention - and we try and live with that and achieve the best we can. The second is that we don't go in and start formlessly on tape and then build a song out of it. The song comes first. After that stage, I think it's when the three of us find something in the song and the way of playing it that sounds like it has value and meaning, and we think 'that's a good song', and carry on from there. It's hard to break things down beyond that, because it either happens or it doesn't happen."

Couldn't you be a little more specific; how did you record 'Downtown Lights' (the first single from Hats), for example?

"It wasn't complicated," says Paul Moore, "it was a song which I suppose basically existed. Paul [Buchanan] played it on guitar and we just joined in with each other."

"Sometimes you're so overcome by what happens to you in your life that a song comes out of it - and we share that." Paul Buchanan

It's a little hard to relate this simple explanation to the track in question - it sounds less like a guy playing a guitar with two friends joining in than almost anything.

"We recorded that quickly, as we were playing it. And we just add anything else that seems obvious to us in the arrangement."

The Blue Nile seem about as willing to submit to a detailed analysis of their recording and writing techniques as most people are to having a tooth pulled without anaesthetic.

"Actually, 'Downtown Lights' is quite a good example of how we work, because there was a point at which we'd been working on it, and it seemed probably to all of us as though the whole track and the whole sound of it was complete; in fact, it was probably only happening in isolated moments in the music, and we were just colouring the rest in with our imaginations. Our job thereafter was to make the music actually shape up to what it already seemed to us to be."

With a little more prompting, Buchanan suggests that part of their reluctance to divulge recording techniques is that, by their nature, they defy simple analysis.

"It's just difficult to describe for two reasons. The first is that it's like when you're driving a car, and you don't remember the last five minutes - there's an aspect of that. The second is that every time you try and make a rule of something, it doesn't work, because each of the songs is different."

Robert Bell concurs: "I think you should approach every song as if it's the first song you've ever heard, or worked on, or thought about, or whatever. Because otherwise it's going to be like other things."

The point about doing something almost without realising how you are doing it is an important one - creativity is more strongly associated with the subconscious than the conscious mind - and with just a moment's more thought, Buchanan takes it a little further.

"I think that because of the pressure after the first album, to some extent we analysed what we were doing, and it takes some time to regain your unself-consciousness. So in a way, trying to break it down, I feel less than ever that I should like to think of it like that. We want people to respond to the mental picture and not to the personalities or the mechanisms behind it. That would be like leaving a camera in shot in a movie."

THE APPLIANCE OF SCIENCE

The use of technology in The Blue Nile's music is not particularly obvious, in that the sounds of synths and samplers are blended with the music's other elements to form an organic whole. As a result, it's certainly not possible to guess what instruments have been used - there are no obvious DX or LA sounds - which is a sure sign that the technology is being used by someone who knows how to get what they want out of it. Paul Moore sums up the essence of the band's relationship with hi-tech thus: "It affects us only in as much as what's available to us changes. So it's possible to record sounds that we didn't have before. Something could occur to us now that would never have occurred to us to do five years ago."

In the period when they couldn't get into Castlesound, the band spent about a year working on songs with the aid of an ex-demo Akai 12-track tape recorder, which turned out to be "very, very handy." As for the equipment that was used on Hats, Paul Moore seems to be more responsible than the others for the technical side of the band's instrumentation, and offers this checklist:

"You should approach every song as if it's the first song you've ever heard, or worked on, or thought about, or whatever. Because otherwise it's going to be like other things." Robert Bell

"Various drum machines, mainly Roland. A Jupiter 8, and anything that was lying about, really..."

"We use whatever we can borrow - the studio's not heavily equipped, we just use whatever we can get our hands on. A lot of the time it's something that's been left in the studio by someone else, so I'll stay up all night working out how to use it."

So what piece of equipment was most useful in recording Hats?

"Er, the Jupiter 8 I suppose. We used a Super Jupiter as well, but it's just not the same."

What about sequencers?

"Well, we work on tape. I'm not crazy about sequencers," reveals Buchanan, and a wry smile crosses his face as he adds, "I'm the luddite in the band."

There are a lot of percussive samples on the album - sounds which, although industrial in their basic character, take on a totally different feel in the context of a track - so are these all played rather than sequenced?

Paul Moore: "Some are played. I think you always hope that the sounds become something else than just a reminder of where they came from. You don't want people to think about what guitar you played, or 'is it a sample'. That's a distraction, and there are better things in music than thinking about what instrument it's played on."

"We would utterly eschew anything that sounded like a good 'synthy' part," adds Paul Buchanan.

Ah, but what about that synth bass sound at the start of '7 am'. OK, it's the only one I could think of, the exception that proves the rule perhaps...

"I haven't quite worked out the logic of that yet, but I'm definitely not telling you what that sound came from ..."

You surprise me.

"... it's one of those things where there is a problem of philosophising or strategising. We looked at many sounds to use for that particular bassline, and that was just the bass, wasn't it?"

"I hope that the sounds become something else than just a reminder of where they came from. You don't want people to think about what guitar you played, or 'is it a sample'. There are better things in music than thinking about what instrument it's played on." Paul Moore

The others nod their assent.

"I haven't quite worked out how to argue about that one yet, but I must say that in the context of that song, I do get a picture from it."

I somehow imagined The Blue Nile to be very meticulous workers in the studio, obsessively slaving for weeks over tracks to bring them to completion. It's hard not to think that of a band whose output is an average of one album - that's seven songs - every five years, but it seems that this is not entirely the case.

"There's no typical time to record a track. The shortest is hours, or a day, and we'd never discuss which song or songs that happened on. But by and large, they all crossed the finishing line at the same time, although some of them may have been more ready just through practicalities.

"Maybe we're using a string orchestra, so when you have them you record whatever you're going to use them on, so that aspects of whatever songs the violins appeared on would be more advanced."

The length of time that elapsed between the two albums therefore has, as much as anything, to do with the band acquiring enough raw material for their work - living a little more of their lives in order that experience can be translated as art.

"It sort of happens to you. I don't mean in any big deal way - lying around being a rock 'n' roll star waiting for inspiration to strike. Sometimes you're so overcome by what happens to you in your life that a song comes out of it - and we share that."

FIVE YEAR PLAN?

The Blue Nile are, in most senses, an unconventional band - they're not a part of the pop machine, yet neither do they set themselves up in opposition to it. They just do what comes naturally, and if that means taking five years to make an album, so be it, and everyone else will just have to accept that. But what are their plans for the future?

"We're going to record the next album in a submarine," deadpans Paul Buchanan.

"Actually," elaborates Robert, "we plan to be less organised."

"We don't have a plan, and I don't think we can. We're in the business of translating emotions, so I don't think we can plan to have a career. It's such a personal thing for us, it's not a career. We want to do another record, but as to what shape it could take, that depends on how we feel on the day, and how our imaginations work, and I guess we don't have any control over that. It makes it hard to plan, but it makes it exciting."

Exciting it may be for The Blue Nile, but for the rest of us it can make waiting for another album a frustrating business - if you let it. I won't be waiting with baited breath; I might just turn blue and keel over, but I know that listening to a new album when it does appear will be a uniquely rewarding experience for anyone with half a heart, and ultimately that's because The Blue Nile allow themselves to be, in a sense, so ordinary.

"We try to use instruments that we can't play. We don't have a big record deal. We don't have any management or road crew. We're not a hi-tech band, we're not an underground band. We're not any of these things. Most 99% of our lives is just doing whatever it takes to lead up to... Hats or whatever."