With six hours before the BBC Radio 2 Folk Awards get under way, the chatter of greying musicians injects some conviviality into the lobby of the Barbican Thistle. Amid the throng, it isn’t difficult to spot John Renbourn. At some point between Pentangle’s dissolution 34 years ago and the lifetime-achievement gong handed to them on Monday by Sir David Attenborough, the group’s 62-year-old guitarist morphed into a blinking, beaming folk Santa — seemingly unsure of how he came to be here, but no less delighted for it.

Terry Cox, the group’s 69-year-old drummer, feels much the same. “Prior to this year, I hadn’t touched my kit for a decade,” says Cox, who now runs a restaurant in Menorca. “People have been trying to reassure me that it’s like riding a bike. But that's no good really. I’ve never ridden a bike in my life.”

At the end of the table is Bert Jansch. In his considered Caledonian mutter, the guitarist is explaining to the group’s singer, Jacqui McShee, what it was like to play last year’s Green Man Festival — a festival whose progressive folk philosophy could have been forged from molten Pentangle records.

If the four musicians gathered here (the bassist, Danny Thompson, doesn’t like interviews) seem to be taking the sudden reappraisal in their stride, it’s probably because it was a little like this the first time round. Cox remembers the furrow-browed concentration with which aspiring guitarists — among them the young Jimmy Page and Nick Drake — would stand before the stage and attempt to absorb what the two were playing. “The joke was that, most of the time, we had no idea what we were playing,” smiles Jansch. Both had recorded solo albums for the new Transatlantic label when Jansch moved into Renbourn’s flat in St John’s Wood, North London.

Jansch says most days there were the same. Sleep till the afternoon, “then get stoned and play for hours”. It was on one such evening in 1966 that the producer Bill Leader arrived with a Revox tape recorder and came away with the short but stunning Bert & John album. “I find it hilarious,” Renbourn says, “that the record has since been revered as a folk-baroque milestone. So much of it was made up on the spot.”

One such improvisation was Bells , the instrumental that eventually graced the Pentangle’s eponymous 1968 debut. Thanks to a passing Danish camera crew, there even exists footage of the two finessing their new composition. What unfolds in those two grainy monochrome minutes is the germination of the seeds that became Pentangle. As far as folk purists of the time were concerned, Pentangle formally set out the point of no return. In an age when Sandie Shaw’s sulky demeanour was still an issue, the sight of the newly installed Jacqui McShee imparting Let No Man Steal Your Time with an air of volcanic portent more commonly found on the face of Grace Slick must have seemed outrageous.

Learnt from Peggy Seeger some years previously, her impassive detonation of the Appalachian song House Carpenter now came with a sitar wig-out, courtesy of Renbourn — an act of folk treachery! McShee now con-fesses that the sombre face was unintentional. “I was terrified,” she says. “That’s why I used to sit on a stool. I tried standing up, but I looked down at my legs and saw them shaking — which, of course, made it worse.”

Asked when they knew that the groupwas finally taking off, Cox tells a story about the time that he saw a cleaner at Wa-terloo Station singing Light Flight while sweeping the floor in time to it. “It stopped me in my tracks,” he remembers, “because I thought, ‘How can he do that?’ The time signature veers between 5/8, 7/8 and 6/4.” Days later, Top of the Pops came calling.So in 1969 Pentangle actually became proper pop stars. In the book that accompanies The Time Has Come , a forthcoming box set spanning the group’s six years together, a collage of Pentangular ephemera contains a centre spread of the group in Jackie magazine. Over in America though, Miles Davis personally welcomed them when they visited the Club Baron in Har-lem. Renbourn’s eyes light up at the memory. “Sometimes I wonder if our manager didn’t give him ten bucks to pretend he’d heard of us.”

Over on the West Coast another well-known Pentangle fan needed no such incentive. At the Los Angeles Troubadour Cox remembers receiving an offer from Charles Manson and his “family”. Did the band want to come and hang out at his ranch in Death Valley? “I didn’t,” says Cox. “I grew up near West Wycombe, near the Hellfire Caves [the 18th-century site of Sir Francis Dashwood’s infamous Satanic ‘revels’] so . . .” Renbourn weighs in: “So you said, ‘It all sounds a bit dull. Let’s give it a miss.’ Priceless!”

A convert of some ten years, the Smiths’ Johnny Marr articulates the reason why so many disparate music fans wanted a piece of Pentangle. “You only had to see pictures of them back in the day to know why people like Led Zeppelin thought they were so cool,” he says. “I remember asking Bert, ‘When you were doing it, did you know that you were, like, heavy? Heavier than all those bands that were heavy?’ He nodded this thoroughly appropriate nod and passed me a biscuit — as if to say, ‘Yes, and I’m too heavy to even talk about it!’ ” By 1972’s swansong album, Solomon’s Seal, though, the rigours of the road had impaired intra-band communications — not least between Jansch, a quiet soul at the best of times, and the other four. It took Cox years to summon the courage to ask Jansch if he had offended him in some way. Jansch explained that he struggled to say anything to anyone before 2pm. Nonetheless, it was Jansch who picked up the phone on New Year’s Day in 1973 to say he was splitting the band.

Thompson became a session musician. Cox opened his restaurant in Menorca. McShee and Renbourntoured for a while in the John Renbourn Group. Jansch released solo albums and confronted his alcoholism. Ru-mours of an irreconcilable rift between Jansch and Renbourn are played down. “There were myths about the band that even we got caught up in,” explains Jansch. “But nothing that couldn’t be sorted out with a phone call.”

For the new “outsider-folk” wave — Joanna Newsom, Dev-endra Banhart, Tunng, Adem, Espers and Vetiver — mentioning Pentangle is something akin to uttering a secret password. They’re not the only musicians who have been reevaluating the most undercelebrated body of work of its era. The process of choosing tracks for The Time Has Come forced the people who made it to do the same. “It was a blast,” says Renbourn. “Just listening to it made me feel drunk and stoned.”

At the Folk Awards, some 40 years after they first performed the song, a similar effect takes hold when the band rough up Bruton Town in a manner that would have Charles Mingus and Ewan MacColl rotating in theirgraves for entirely different reasons. With delicious inevitability, Light Flight also gets an airing. True to form, McShee smiles only once it’s over.

At last year’s Green Man Jansch and Renbourn played on separate stages and separate days. Would it be too fanciful to imagine all five members headlining on the same stage this year? Hours previously, they didn’t seem so sure. And now? McShee, Jansch and Cox say they’re open to a short series of dates. Thompson, apparently, is also “fired up” by the reunion. And Renbourn? “I was finally going to retire this year. This damn Pentangle stuff is an annoyance.” An annoyance he feels compelled to go along with? “Well, kind of,” he says, softening. “Kind of.”

The Time Has Come is released by Sanctuary on Feb 26. John Renbourn plays Hitchin Folk Club, Herts, on Sun (01462 812391)

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