There are few living artists who can justify the title of "legend"; Joan Baez is undoubtedly one of them.

A pioneer of the 1960s folk scene and a leading light of the international human rights movement, her influence has been long, strong, and humble.

It's remarkable that such an icon will, at the grand age of 71, be treading the boards at Plymouth Pavilions next month as part of an extensive UK tour. But, as Joan says, while she can still sing and people want to listen, then she's delighted to be carrying on the troubadour tradition; accompanied by multi-instrumentalist Dirk Powell, she'll be sharing a repertoire that spans a career that's crept into five decades.

"When I call from tour, my friends tell me I'm the happiest I ever am," says Joan, who lives in California close by her 98-year-old mother, her son and her grandchildren.

"I've had some time here at home and now I'm ready to go. When I stop singing there will be plenty of other things that I would like to get engaged with. But at the moment I'm still doing this. Mind you, it used to be so easy to sing, but it's not any more," she confesses.

Her journey across the Atlantic coincides with the 50th anniversary of Amnesty International, and the release of a celebratory album called Chimes of Freedom – The Songs Of Bob Dylan a 75-track compilation of major artists covering Dylan songs. It's fitting that Joan is on there – alongside a diverse roll-call that includes Adele, Pete Townshend, Elvis Costello, Sting, Miley Cyrus, Johnny Cash and Dylan himself. Amnesty last year bestowed on her the inaugural Joan Baez Award for Outstanding Inspirational Service in the Global Fight for Human Rights.

On the four volume collection she's singing the haunting Seven Curses, Dylan's adaptation of a Child ballad from 1963 – the year Joan unselfconsciously introduced him to the world. She recorded his songs, the pair toured together, and their bond came to symbolise the contemporary folk scene.

"We come from the same perfect storm," she says, simply.

Joan as performer first entered public consciousness aged 17 with her debut at the 1959 Newport Folk Festival and a residency at Boston's famed Club 47. Her earliest recordings fed a host of traditional ballads into the rock vernacular. As well as Dylan she also focused awareness on a host of great songwriters ranging from Woody Guthrie, Phil Ochs, and Tim Hardin, to Kris Kristofferson, Mickey Newbury, Richard Shindell, and Steve Earle.

"I didn't plan to have a career – it just kind of happened – and I never dreamed it would go on for 50 years," she says. "Sometimes when I'm there in front of a crowd it all seems crazy. If I'd planned it, I might have looked more carefully."

In tandem with performing she marched on the frontline of the civil rights movement with Martin Luther King, sang on the first Amnesty International tour and stood alongside Nelson Mandela when the world celebrated his 90th birthday in London's Hyde Park.

"I was a political animal before I learned to sing," she says. "In the 1960s protest was seen as a bad thing. But courage is contagious as well as violence. By just doing it I helped other people to do it. I learned about courage from Dr King and people like that. And, of course, I had my own that I was born with. I came from a background of peace – my father worked for Unesco; I realised I could make changes and I was comfortable with that."

She says that in the last 40 years no really strong campaigners have emerged from the music world.

"There are probably a lot of musicians out there standing up for justice and peace, but they are probably not that good. And if you want to express yourself it takes more than good thoughts. Every kid wants to write an anthem, but it takes genius to do that," she observes.

Joan still harvests her songs from the cream of writers: "I beg, borrow and steal them.

"I choose and use songs carefully."

Day After Tomorrow, her most recent studio long player from 2008, named after the Tom Waits track covered, was her first in five years. Produced by Steve Earle who also plays guitar, its themes of hope and homecoming also explore the individual and collective anguish of life during wartime.

Some of these will find their way onto a setlist that's a work of art.

"It's important to make the set work rhythmically and at the right pitch to keep it going. It's my responsibility to put together something that is representative of me."