When guitarist Peter Green departed Fleetwood Mac in May 1970, it was a sad relief for both Fleetwood and Mac. By that stage, Green had completely lost the plot. He was wearing robes and crucifixes, he was seeing angels and he had given away most of his money. He was also anxious that Mick Fleetwood and John McVie should be equally charitable, but they declined. They were on the way up and Peter Green was certainly on the way down.
And so began a long spiral into troubled times. "Far too much acid," people said as they searched for clues in songs like Green Manalishi, Man of the World and Albatross. The clues were there, too, as to what exactly was bothering Green - fame and money - and as he vanished into a world of institutions, medication and work as a gravedigger, he was soon only mentioned in terms of doubtful Presleyan sightings.
In the early 1980s, there was something of a reappearance, but those who saw him play were shocked by what had become of the slimline guitar hero - both the physical transformation and the fact that he now barely touched the guitar. Soon he stopped playing completely. His fingernails grew and that, it seemed, was that.
However, while the Peter Green myth is imposing, the reality is equally daunting. Interviewing him is far from easy. Yes, he is talkative, good-humoured and open, but it's as if he never quite understands the question (and the interviewer never quite understands the answer). This can make for a confusing but good-natured ramble.
We begin in 1960s London, when Peter Allen Greenbaum first went along to see "God".
"I was taken to see The Yardbirds by some chap - I think he was someone famous himself," he says. "He was in another real great group, but I didn't know it at the time. He took me to see The Yardbirds and we were told they were good - better than The Rolling Stones. So we went along and there was Eric Clapton. What he used to do was pretty skilled stuff. A craftsman, a skilled craftsman, I always thought. But it was still music. You wouldn't forget it was music."
Green himself was soon up on the same pedestal as Clapton, replacing him in John Mayall's Bluesbreakers in 1966. Fleetwood and McVie were also in the band, and a year later they all left to form Fleetwood Mac. Their first number one came with Green's instrumental, Albatross - a perfect choice of sea bird as it turned out. Green, now known as "the Green god", simply couldn't cope with his success. He questioned everything, took a lot of drugs, became a recluse - and so on and on.
Back in London's East End, however, it had once been all about music - everything from Hank Marvin to the religious sounds of the synagogue.
"And then there was Les Paul and Mary Ford - my brother had a record of theirs," Green says. "So when I was a kid I knew the name Les Paul. I remember Jimmy Rogers. I had a blues record with Jimmy Rogers on it and I remember his name specifically because there's two of them. There's the famous one - the country and western one - and this one who hadn't got the 'd' in his name. Dr Ross I liked, but I couldn't really catch on to any of the other stuff. It was a bit too whatever for me because of where I was with rock 'n' roll brainwashing - or pedigree - whichever you want."
Green first got involved in the 1960s music scene when he joined Shotgun Express, a band which featured Rod Stewart on vocals. After that, it was the stellar network which centred around John Mayall and ultimately spread out around the world. Between them, English acts such as The Rolling Stones, Clapton and Green popularised US blues and rhythm and blues not only in Europe, but also back in the US, where it was far from appreciated. They represented the music to its home and guitarists/enthusiasts such as Clapton and Green began to feed back into the source.
"We were just trying to learn all this stuff, this blues," Green says. "You've been playing such a long time with Buddy Holly music and Everly Brothers, you're so familiar with these songs, so then you can see what damage you can do to playing blues. But when you got out there, they were glad to get you off the stage. You're still learning. Innocence - you can't turn your nose up at it."
But Green, despite his protestations, was particularly well-regarded in the US. In 1998 he was inducted into the Rock 'n' Roll Hall of Fame, Carlos Santana taking to the stage to perform Black Magic Woman with the man who wrote it. Gary Moore, who proudly owns Green's 1959 Les Paul, put together a tribute album called Blues For Greeny and there were many others who kept him constantly in mind. "He Gary Moore was probably someone who was concerned, someone who had a thought for me," says Green. "A thought to Peter in case he's critically ill . . . or some joker is making him feel like he is."
But Green really was ill and although he denies that, at one point, he actually had to re-learn the guitar, he did find himself thinking carefully about how to approach his instrument afresh.
"What I did was I 'basic-ed', I 'rudiment-ed' - made it rude and bare and stripped it down. Style is dangerous because if you're stylised you're an accomplished musician after a fashion. You could throw it away and play in another style. Does style mean that it's not music? This style or that style. Does it mean that people stylise rather than orchestrate? Every day I learn to be a little more style-less."
These days Green records and performs with The Splinter Group. Here he has the comfort of working with his old pal, Nigel Watson, and certainly there were times when real friendship was needed. Those early Splinter Group gigs were nervous affairs as Green was re-emerging, searching for confidence as much as for the right note. In fact, it was while Green was living in Watson's house for nine months in 1995 that guitars finally began to reappear. It is tempting to conclude that, despite the difficulties, he simply couldn't live without the music. Green, however, makes sure that temptation is resisted.
"Music is not important at all," he says, "although it keeps you whistling in your head rather than moving around the streets looking at other people. It keeps you at home.
"I was an indoors child and so music was always there. So if you don't want to wander the street and mug other people or you feel a bit sick, you can stay home as long as you like. You could have music there, but you don't need it. I like to meet other people who prefer the peace of the countryside - or not really the countryside but the forest - the peace of the forest. I'd be quite happy to join a reservation of Native Americans. I'd have to give up music and I'd be fairly happy to."
Maybe so, but in the past five years the once invisible Peter Green has performed over 400 gigs and recorded two live and three studio albums (the third, Time Traders, is just out on Eagle Records). As for the old stuff, will any of that be scribbled on the set-list for Monday night?
"I'm happy to play very old stuff like Autumn Leaves," he laughs. "It should be quite nice. Old Fleetwood Mac songs I don't want to do. I did it so many times. If they want me to do it then we'll have fun at it, but I'd rather not do it. The preference is that I don't go backwards. But it's getting better all the time. Every performance I play better than the one before."
Peter Green and The Splinter Group play Dublin's HQ on Monday