FOR almost 40 years, it seemed as if Shirley Collins had gone to ground.

Hailed as England's greatest folk singer, she spearheaded the 1960s and 1970s folk revival, and toured America with folklorist Alan Lomax, collecting songs that would be pivotal to Rolling Stones riffs, Moby hits and the soundtrack for O Brother, Where Art Thou. She released several canonic albums, including 1964's Folk Roots, New Routes (with Davy Graham), and 1969's Anthems in Eden, in cahoots with her sister Dolly.

But in 1978, she withdrew from performance, so traumatised by a marriage break up that she suffered a debilitating vocal condition known as dysphonia, which meant that for decades she was unable sing.

During Collins' enforced absence, when she raised a family and ran an Oxfam shop in Brighton, her vital work as a folk conduit and pioneer carried on through her songs, mapping our collective past, shining a light on our lives and our land. Her voice – always bright and beautiful, yet never eclipsing the song – found avid fans including Billy Bragg, Blur's Graham Coxon and Current 93's apocalyptic folk diviner David Tibet.

Tibet slowly encouraged Collins to find a way back to her voice, and the stage. In February 2014, almost four decades since she'd last sung in public, she performed at London's Union Chapel. Now, she's set to play in Glasgow, armed with a wonderful new album, Lodestar, her first LP for 38 years. It's released on Domino, which makes Collins label-mates with the Arctic Monkeys, Buzzcocks and Franz Ferdinand. She was always quietly radical.

Shirley Collins was born in Hastings, East Sussex, in 1935. She and Dolly were discovered as teenagers by English folk chronicler Bob Copper, who became a life-long friend and champion. The first time they met him, however, these trailblazers of the English folk tradition regaled Copper not with a paean to Eden, but with a ballad from Scotland. Legend has it they even adopted Scottish accents for the occasion.

“Oh, that's absolutely true,” says Collins down the landline, through hearty laughter. “I wrote to the BBC when I was 15, to let them know I wanted to be a folk singer. Luckily, Bob Copper was working there at the time, on field recording trips, and they passed the letter to him. When you think about that, it was a miracle. One day, Bob turned up on our doorstep.

“Dolly and I thought we ought to impress him,” Collins continues. “So instead of singing some of the songs that Mum and Aunt Grace and Granddad used to sing to us, we'd learned a song from the McEwen brothers, off the radio – The Bonnie Earl O' Moray. We sang it as much like them as we could.” Her voice is full of kindness and mirth. “And yes, we tried to do the Scottish accents.”

What strikes most about this tale is that Collins was so clear-sighted at 15. Does she recall when she decided to be a folk singer? “Well, yes,” she nods. “It's a soppy teenage story. Dolly and I used to go down town in Hastings on Saturdays – we'd go to the pictures. And we saw this B-movie called Night Club Girl. It was the story of a Tennessee mountain girl, who was discovered by a talent scout, singing folk songs in the mountains. They whizzed her off to New York, and there she sang in night clubs in sweet frocks. She fell in love with the owner of the night club, and he was an actor I was rather crazy about. So I thought – 'Oh, that'll do for me. I shall be a folk singer.'”

An upcoming film, The Ballad of Shirley Collins, will celebrate how she did just that, and so much more. Collins became one of England's best-loved voices – a national treasure – and she also played a cardinal role in upholding American folk traditions. In 1959, she sailed to the US with ethnomusicologist Alan Lomax, collecting field recordings, as gloriously documented in her 2004 book, America Over The Water.

Their tape of Trouble So Hard, by Alabama washerwoman Vera Hall, would underpin Moby's hit Natural Blues. Their work with blues guitarist Mississippi Fred McDowell had a formative influence on the Rolling Stones. And James Carter and the Prisoners' Po' Lazarus featured on the Grammy Award-winning soundtrack to O Brother, Where Art Thou.

Lodestar includes two songs from that journey, including Pretty Polly, from Arkansas. “I recorded that myself, because Alan was in the next room with Ollie Gilbert's husband, who was a moonshine maker, and they were having a very pleasant afternoon to themselves,” she recalls. “I was sent off to join the womenfolk in another room, and recorded songs from Ollie all afternoon.”

There are also songs collected by Copper, and from Collins' childhood, on Lodestar. “They're songs I've always wanted to record,” she says.

“The Silver Swan goes back to my days as a teenager. We used to sing it at home – Mum and Dolly and me – trying to sing the five-part madrigal, never succeeding, and ending up with lots of laughter.”

Collins' work resonates with such celebrations of women's voices, women's lives. Her first Glasgow concert in what she says is “centuries” (it's certainly decades) at Celtic Connections will feature, among other thrills, a female Morris Dancing team. And she delights in recalling how she'd wind up patriarchal folk purists such as Ewan MacColl back in the day. “He disapproved of me wearing nail varnish,” she tuts. “I had no time for MacColl. He was pompous. He was pretentious.” She chuckles under her breath. “And I didn't like his singing. Or the rules he laid down for people.”

She defied the male gaze, too. Her frolicsome take on Hares on the Mountain, recorded with Davy Graham, sees her wryly objectify and lampoon the opposite sex. (“Young men are given to frisking and fooling / I'll leave them alone and attend to my schooling,” she sagely concludes). “It's sort of cheeky isn't it?” Collins muses.

“There's a control in there, and [the sense] that actually we're in charge, really. I sing several songs where women get the upper hand. That's to sort of counteract the many more where they unfortunately don't. . .”

The menfolk don't come off great either, as is often the way in traditional song. Lodestar's litany of woebegone fates was a source of amusement while making the record, as Collins attests. “We recorded everything in my cottage here, and one morning Ian Kearey, who's the album's major accompanist, producer and musical director, burst through the front door and said – 'Right, what's the body count today then?'” She bursts out laughing.

Recording in her Lewes home allowed Collins to rediscover her voice in her own space and time. “We took it as slowly as we needed to,” she says. “I hadn't sung properly for a while, and I wanted it to be as good as possible. But I had to accept that my voice has got much lower, and it's not as reliable. I had to learn to live with that.

“Except, I did get really worked up sometimes,” she adds. “I'd get cross with myself if I wasn't doing things well. And so I'd start to swear rather a lot.” More laughter. “Finally, I decided to get a swear box. I said to Ian and Ossian and Steve, who were recording the album, 'I've got a swear box on the table now. Every time I swear, you have to put in a pound.'”

Shirley Collins, turning the air blue.

There's a comet in the night-sky on the cover art of Lodestar. It's part of an 18th-century painting, and was brought to Collins' attention around the time her daughter sent her an idea that became the album title. “There's a sort of magic in that coincidence, isn't there?” Collins beams. “When my daughter texted me that word – lodestar – I looked at the dictionary, to make sure I knew what it really means.

“I read it was the guiding principle, the North Star, and I thought – 'That's absolutely right,'” she says. “Because music has been my lodestar for as long as I can remember. This music has meant that much to me, through all the years. Even though I wasn't able to sing.” She recalls her shock (and tears) when David Tibet first phoned her during that time, to tell her how very well-loved she was. “I just had no idea,” she quietens. “I thought I'd been forgotten.”

Under the comet, Collins is pictured cradling a sextant, as she once did a banjo. It's an archaic instrument, used for celestial navigation and reflecting on horizons. Collins, too, has long helped us find our place in the world. Almost 70 years since she first sang for Bob Copper, the voice she once lost is more precious than ever: old as time, warm as home and bold as starlight. She leads the way.

Shirley Collins plays Glasgow City Halls on February 4 as part of Celtic Connections. Lodestar is out now on Domino Records.