Unsurprisingly, everything you might have heard about Bert Jansch is true. He is the most modest of legendary guitarists, not one to talk about himself or his achievements in any great depth. He is quiet, shy and evidently not one to throw himself into interviews, and fully deserving of sometime-collaborator Bernard Butler’s description as “this quiet, unassuming, but hugely revered master”.

At the moment, however, Jansch’s discomfort in the limelight is alleviated by the fact he must share it with the four other members of Pentangle. After twelve months of sorting it all out, the five original members of this most seminal of bands will tour the UK this summer, including an appearance at the Mecca of new folk, the Green Man Festival.

As supergroups go, they take some beating. For the benefit of anyone unschooled in all things Pentangle, let’s examine the credentials of each member when the band formed in London in 1967. Jansch himself had released several solo albums of innovative folk guitar and had caught the ear of a young Jimmy Page, a distant Neil Young and a brooding Nick Drake – all of whom confessed to taking huge inspiration from him. The other guitarist, John Renbourn, was more from a jazz background and easily one of the finest practitioners on the London scene. Bass player Danny Thompson was part of blues master Alexis Korner’s band, played with Tim Buckley when he came over and of course went on to form an extraordinary partnership with John Martyn in the early 70s.

He is regarded as the finest stand-up bass player to grace the folk/jazz field. Drummer Terry Cox had also played with Korner and was a well-known talent, while singer Jacqui McShee, well, she was a stalwart of London’s folk clubs in the early to mid-60s by the time Pentangle formed. It was and is a line-up, as their name suggests, of five equally important components.

Jansch recalls the circumstances in which they got together.

“John and I used to live together,” he patiently recites, “it was more of a necessity than anything else, needing a place in London. Because of that we got to know each other very well, musically. We decided we wanted to start our own club, which we did, The Horseshoe, on Tottenham Court Road. We invited all sorts of musicians to come along and the band grew out of that. The first gig we did away from The Horseshoe was at the Festival Hall.”

Appropriately, it is on the South Bank where they will begin their tour on 29 June. The Horseshoe, inevitably, is long defunct. Pentangle themselves lasted until 1973 and released six albums… by this time they had more or less been on the road constantly, and to cut a long story short, as Jansch says, “it got so insular… it was like a marriage breaking up.”

Pentangle are one of those bands that have always been a bit of a bastard for critics to define. Not folk, not jazz, certainly not rock, they are a unique combination of all three. In Renbourn they had one of the great musical renaissance men, whose appreciation of hugely diverse genres rubbed off on the rest of the group. The key to them, however, seems to be the fact that the usual restrictions on individual talent, ambition and sensibilities were non-existent in Pentangle. Each member was free to explore what they wanted, and the others would fit in with that.

“That’s the thing about the band,” says Jansch when asked if he adapted his songwriting for Pentangle as distinct from his own solo career, “it fitted in with your own abilities, you didn’t have to alter anything. And that applied to each of us and why we ended up doing solos in a jazz sense. Danny would take a bass solo, Terry would take a drum solo. We had room for that kind of thing. That didn’t happen in the rock school.”

The specific dynamic between Jansch and Renbourn has always been fascinating – they had released the excellent Bert and John album in 1966 as a duo. Students of the 60s folk boom and Pentangle obsessives are able to pick apart their differing styles (“Renbourn’s time signatures are all strange”… “Bert was the more soulful”) and identify what each brought to the band, but the philosophy of Pentangle dictates that no such thought ever went into it.

“There were no designated slots,” says Jansch. “How numbers came together was that if it was a number that you played, everyone had to fit round what you were doing. If John was coming up with a number then John would take the main part and everyone would fit round him. It was very much an organic thing.”

More than once does Jansch mention how Pentangle were “way ahead of their time” and says “it’s remarkable how it holds up to stuff from today”. Indeed, compared to their late 60s contemporaries who fused folk with other styles like Fairport Convention (blues/rock) or Jethro Tull (heavy rock), Pentangle come across as, well, a bit more sophisticated. And though Dave Swarbrick might argue, the more adventurous musicians.

America responded back in the day, too. But, as with several European tours, Pentangle were placed on bills that were simply wrong.

“We were regarded quite favourably as far as I can remember,” says Jansch of their reception in America. “Some of the big shows we did though, how we got away with it I’ve no idea. At one point we did Fillmore East with Rhinoceros and Canned Heat, we were the bit in the middle, that was the bill! We did the Fillmore West with The Grateful Dead and it was enormous. It was strange to go on stage with just my AC30.”

Tiny amplifiers aside, Pentangle developed a large following in the States, and indeed perhaps this current revival might stretch that far… one thing at a time though, it was a long road to this tour alone.

“It was directly through the folk awards,” says Jansch, referring to the 2007 BBC-sponsored night, where Pentangle received the Lifetime Achievement gong. “They wanted to give us this award and wanted us to play on the show, and I think we were surprised that each member of the band actually said yes. And the rehearsals for that were absolutely fantastic, although the actual performance wasn’t that good. But it did bring us together.”

They have, of course, gotten together before – in the 80s they reconvened, but health problems and other musical commitments ensured no great fluency was achieved, though under the moniker of Jacqui McShee’s Pentangle, she has managed to keep an incarnation on and off the road since then.

This time feels different. Who knows, maybe even new songs might emerge.

“That will depend on how well this goes, it is going so well at the moment. It will be successful as long as we enjoy it, and that comes across on the stage.”