Age has not withered Peggy Seeger. Now 81 and sharp as a tack, she recalls her first meeting with the folk legend Ewan MacColl without a trace of sentimentality. "He was married. He was 20 years older than me. He was old enough to be my dad. And he had a child. It wasn't my idea of what I wanted to get into."

In 1956 Seeger was a bright young American, barely out of her teens and hitch-hiking her way around Europe. MacColl was on his second marriage and well on his way to a paunch. The relationship ought to have perished before it began – but he was persistent. “I kept trying to stop it, but he wouldn’t allow it,” Seeger says. “And from the moment we decided to get together in 1959, it really worked.”

What was it that drew Seeger so strongly to MacColl? “Oh, the music,” she says. “And we agreed so much on political matters – though he had more political nous than I did. I’m hopeless. I can’t list the feminist heroines or the political heroes. I don’t have the ability to co-relate this with that with the other. Ewan did have that.

“For him,” she adds, “what I had was youth. I had instruments that I could play – and he couldn’t play any instruments. I was American. I was female. He was passionate and I was more relaxed about things. It was a good mixture. He died 27 years ago and I think about him every day. He comes to my mind every day. I mean, he’s in there.”

Her friend Irene Pyper Scott is now her partner. She has commented: “I’m not bisexual; I just happen to love a woman. I loved a man.”

They say music is a family business, but the partnership of Seeger and MacColl – they finally married in 1977 – gave rise to something more akin to a musical dynasty. Seeger’s half-brother Pete was another legendary figure on the folk scene – still is, despite his death in 2014. Kirsty MacColl, daughter of that aforementioned second marriage, who died in a hideous boating incident in 2000, was an extraordinarily gifted interpreter of songs across a range of genres.

Meanwhile, the two sons from their own marriage are accomplished musicians who have played with everyone from David Gray to Elbow. They'll join their mother onstage at the National Concert Hall for Blood and Roses: the Songs of Ewan MacColl, and not for the first time.

“Well, Neill came out in concert with us when he was 12,” says Seeger, “and Calum came when he was 10. He wasn’t quite ready, but he was ready by the time he was 11, believe me. He learned a lot from that tour. And they are my favourite musicians to play with, because they understand where the music came from, how it was made, and also they understand how Ewan wants the songs sung.”

Playing by the rules

Seeger’s use of the present tense is interesting. A central figure in the revival of English folk music in the 20th century, MacColl senior was famously prescriptive in his approach, drawing up controversial rules about which songs should be sung, how and where they should be sung, even how musicians should dress.

These days, Seeger is more sanguine. “Once you sing a song, it’s out there,” she says. “It’s no longer yours – either in style or, sometimes, even in content. People change it. They do what they want with it. That’s the way things are.”

No mean songwriter herself, Seeger penned a number of feminist anthems such as Come Fill Up Your Glasses and I’m Gonna Be An Engineer. Her most recent album, 2014’s Everything Changes, was praised for its creative energy and willingness to experiment. Which of MacColl’s 300-plus songs does Seeger most enjoy singing now?

“I hardly sing any of his songs,” she says. “So many of them are man-orientated – or they’re orientated towards industries that I think are destructive. Fishing and coal and things like that. Boxing. I haven’t sung any of the gypsy songs because I feel they’re English, and I’m not English. I mean, I can’t sing ‘I’m a free-born man . . .’

“He wrote very few songs that really were for women to sing. Mind you, I am singing some on the Dublin concert. Ballad of Accounting, with Chaim Tannenbaum. Nobody Knew She was There. And one other I can’t remember right now,” She laughs. “But I shall have to rehearse it.”

Short and sweet

One song Seeger won’t have to rehearse is The First Time Ever I Saw Your Face, which MacColl wrote for her. The first time ever she heard it was when MacColl sang it to her down a transatlantic phone line. “I was in Santa Barbara and I had a radio programme in Los Angeles and they wanted a modern love song that was short,” she says. “I didn’t have one. I said that to Ewan, and over the phone he sang me that song. I took it down and made an accompaniment to it – and I never heard him sing it again.

“Somebody has told me that they’ve heard a recording of it – and it’s just possible, because he sang it to me in the January or February of 1957. I didn’t see him until July. So it’s possible that he was singing it in a club somewhere; and if anybody has a recording of him singing it, I would love to have it.”

The song became a huge international hit for Roberta Flack in 1972. MacColl, however, was not impressed by the American singer’s interpretation. “I like it now,” Seeger says, “but when we first heard it, Ewan thought she milked it. Of course, all it was was a different style of singing. And now it has been recorded in every different style that you could imagine. There’s even a rap version somewhere. There’s country and western with banjo playing, there’s gospel, there’s barbershop quartet four-part harmony.

“It’s a warhorse that really should have died from so much tinkering with it. I love most of what I hear, but I still sing it the way Ewan wanted it. He said he created it as an hors d’oeuvre – a starter. Most people have made a main meal out of it. He said they drag it out. He meant it to be like the heartbeat on a cardiograph. The squares and the lines on the cardiograph paper are what I do with the accompaniment, and I sing the heartbeat.”

Is there an irony in the fact that the song for which MacColl is most remembered is not a folk song?

“You can’t write a folk song,” Seeger says. “A folk song makes itself. But you can write a song that sounds like a folk song, and Ewan wrote this with one of the folk song features where the first five words repeat. That’s a folk song motif – incremental repetition. That song has it in all three verses. It’s totally economic. I love singing it. I absolutely love singing it. I’ve sung it for 60 years.”

Blood and Roses: the Songs of Ewan MacColl is at the National Concert Hall on October 11th. Peggy Seeger, Neill MacColl and Calum MacColl will be joined by Martin Carthy, Eliza Carthy, Chaim Tannenbaum and Declan O'Rourke.