'I miss the sea sometimes," says Peggy Seeger wistfully, "but if you listen closely enough the A4142 sounds like the sea …" Transforming the Oxford ring road into an ocean is quite a leap of the imagination, but nothing seems beyond bounds where Seeger is concerned. Back in the 1950s, this American interloper changed the face of British music – and broadcasting, too. Her partnership with Ewan MacColl created the most famous and controversial folk club in the land, the Singers Club, and helped both to revive folk and align it more closely with leftwing politics. Meanwhile, the Radio Ballads, the groundbreaking documentaries the pair made with Charles Parker, made regional accents acceptable in a broadcasting industry dominated by clipped home counties. More than half a century on, their work still provokes ferocious debate.
She's 79 now, and as she pours coffee in the rambling garden of the house she shares with her partner, Irene Pyper-Scott, the setting is so idyllic you expect Miss Marple to pop up any minute. Yet Seeger remains as passionate and uncompromising as ever.
She's been in the wars in the last couple of years – two back operations (one following an attempted dive that turned into a bellyflop), a mastectomy and, most recently, stomach surgery that nearly proved fatal. Yet there's nothing remotely self-pitying about her, and her poetic, lilting, phrases bely her claims that "every time I have an operation it takes away half my brain".
She has a tender and disquieting new album out next week, and it will surprise anyone expecting traditional song, banjo arrangements or overtly political material. Largely written by Seeger herself, it shows a brooding preoccupation with death, whether involving heroin, dementia, car crashes or the Titanic. She decribes the album as "dark – not black, but deep chocolate with burgundy wine".
The decorative, piano-accompanied title track is an autobiographical reflection on childhood, inspired by memories of her mother, the pianist and composer Ruth Crawford.
"I lost my mother when I was 18 at a time we weren't getting along," Seeger explains. "I was sent to boarding school at 15 because I was so horrible to my mother. I put no fault on her – she just didn't know how to cope with a rude, sulking teenager … She'd started her creative life again; it's a tragedy she died so young. If she'd lived another 25 years she'd have flown, but she didn't get the chance. Cancer runs in our family."
So does the American folk tradition. Her father, Charles Seeger, did pioneering musical research, brother Mike was a fine singer and musician in his own right, and half-brother Pete – who died earlier this year – was one of American folk's defining figures. Her son Calum MacColl has produced the new album. "When I first asked to hire Calum he said, 'You can't afford me!' I told him I'd pay the going rate, and he said, 'OK, but when we're working I'm not your son – I'm your producer and musical director, and if I say you're out of tune, then you're out of tune."
Almost casually, Seeger recalls the folk and blues legends who would routinely drop into the house in Washington DC, where she grew up.
"My mother didn't take to Woody Guthrie visiting – he was a bit too rough for her. He'd put his guitar on the floor, pull it around by the strap and pretend it was a dog. And I remember going to the door aged five or six, and there was this huge black man there, and I thought, 'Wow!' That was Leadbelly. Later, I sang with Big Bill Broonzy at the Gate of Horn in Chicago for three or four weeks. We'd start at 11 at night and finish at three in the morning. It was a little dive, but it had the best burgers you ever tasted. And Bill would sit there drinking brandy straight. He didn't say much. He had a pink Cadillac and took Blind Lemon Jefferson around in it. I met Mississippi John Hurt, too. My sister's rotten husband wouldn't shake hands because he was black. John didn't say anything – he just left."
Hitchhiking around Europe in the mid-1950s, Peggy received a phone call from the US folk song collector Alan Lomax, who was in London and needed a banjo player for a TV show.
"I was in a youth hostel in Copenhagen. I'd just been saved from a Catholic priest in Belgium who was trying to talk me into taking charge of a nearby nunnery – long story. I was then going to Finland with a logger who told me my eyes were the colour of time when Alan asked me to come to London."
It led to her fateful meeting with Ewan MacColl, who was twice her age, but became her musical partner, collaborator, fellow political activist, soulmate and eventually her husband and father of her three children.
"He gave me a ticket to see him in The Threepenny Opera where he was the ballad singer. He was 41 and had a bit of a paunch by then. He had braces and dirty trousers and makeup that made him look twice his age. But I was entranced by his voice. Two days later, he told me he was in love with me and was going to make love to me. I didn't even know what lovemaking was. In America, you either screw or you fuck. So that was romantic. Then I found out he was married with a child. But he was fascinating. For 30 years he was fascinating and I was never bored. He said I was free to leave him. And, of course, when you're free to leave, you stay."
That free and easy attitude did not always extend to the folk scene, however. MacColl and Seeger's doctrine that singers must only perform material from their own background, (a policy proposed by Peggy after a particularly misjudged attempt at a blues by a young Long John Baldry) and the self-analytical masterclasses of their Critics Group, are the stuff of legend.
Seeger groans. "We were snobs. We made a study of other cultures and the way they sang. We were trying to work out a way of singing that was true to the music because it's different from other sorts of music and has a class allegiance. It's not about showing how well you can sing; it's about representing a way of life. We tried to work out a way of doing it, but we went about it the wrong way."
In 1957, MacColl wrote The First Time Ever I Saw Your Face for Peggy. Fifteen years later, it was a global smash hit for Roberta Flack, but the not-insignificant royalties accrued from this and numerous other versions – Elvis included – don't temper her distaste for Flack's version. "We hated it. It milked the song, especially the ending. Ewan wrote it as an hors d'oeuvre and it got turned into an entrée."
Seeger couldn't sing it for 15 years after MacColl's death in 1989 – it was just too painful – but it's now back in her repertoire, and in 2012 she herself even added to the bizarre trail of alternative versions, growling her way through the dance beats on Broadcaster's Folksploitation.
Among her own great songwriting achievements is one of the ultimate feminist anthems, I'm Gonna Be an Engineer. "I wrote it for one of our Festival of Fools shows, at which, ironically, there were eight of us women on stage in very short miniskirts. Oh dear. When it was taken up I didn't know anything about the feminist movement, but I was suddenly being invited to all these radical meetings and when I sang it they said, 'Sing another one,' but I didn't have any more. I just had folk songs – which, let's face it, are hardly feminist. That's why I started writing women's songs."
She first met Irene Pyper-Scott in 1964 and sang with her at demonstrations. "After Ewan's death she picked me up, dusted me off and we became more than friends," Seeger has said. "I'm not bisexual; I just happen to love a woman. I loved a man."
One of the most telling tracks on the new album is the gently poignant When Fairy Stories End, which betrays a surprising interest in Princess Diana. "I was fascinated by her in the same way I was by Marilyn Monroe. They both loved being in the public eye and they both died from it."
She laughs when I ask if she's mellowed – "Oh, I don't know about that, but I've certainly slowed down" – and in the next breath is vigorously voicing her concerns about the future of the planet. "It's the assumption that the only way to solve anything is with wars and violence. Sometimes it does seem there's just a whole stack of rampaging men who just love getting out there and battling. How do you deal with that? I'm frightened a lot of the time. The world is in danger."
For all that, her eyes are firmly fixed on the road ahead. Once she's recovered from another operation, scheduled for the autumn, she's planning a major tour next spring. "I've got another 15 years ahead of me, I think," she says, smiling.
• Everything Changes is released on 1 September on Signet/Red Grape.
