Joan Baez, Royal Festival Hall

The next revolution of civil disobedience is unlikely to be a ticketed event, with a sedentary congregation of grey-haired, nostalgic former hippies. And the Royal Festival Hall (even at full capacity) is a mere campfire compared to Joan Baez's public of 30,000 protesters of Washington DC in 1967. But politics, where the drum stick is eschewed for the brush, were still the unspoken substance of her first London performance of four.

“The tour before this was in Latin America,” she began in between songs while slowly changing guitars, “…and it was an honour to play in all those countries I was banned from in 1981,” she continued, to a wave of respectful applause and warm laughter of recognition. Masterful with a punchline, the art of her delivery is an understated soulfulness that, when coupled with the clarity and agility of her voice, allows poetic lyrics to resonate, leaving behind a gentle echo.

Under her treatment, lyrics from Bob Dylan’s "Farewell Angelina" - "the sky is embarrassed/And I must be gone/the machine guns are roaring/the puppets heave rocks" - left open questions about the modern world for discussion, rather than indulging in the otherwise debilitating sadness of those lines. “My trademark is songs of misery” she joked later, before singing the tragic Latin legend "The Weeping Woman", and indeed her unusual talent is founded upon that ability to interpret stories of suffering to create music of consciousness.

While some songs in this varied set showed their age, sung with the excusable complacency of such a long career, this only accentuated the vibrancy of her South American repertoire. Particularly on "La Llorona" and encore piece "Gracias a la Vida" Baez - daughter of a Mexican and an Englishwoman - embodied the fusion of her roots, integrating subtle elements of flamenco finesse in her guitar-playing and of a more flamboyant, richer vocal persona, which seemed to liberate her physically from her Anglo-Saxon reserve. At other times she stood, bathed in a simple spotlight, with a girlish vulnerability when some notes fell slightly flat or broke between the octaves she used to glide through with the nonchalance and grace of a bird in flight.

When not singing alone Baez relied upon a small ensemble to highlight the diversity of her song choices. In an adjacent puddle of light, flitting effortlessly through an arc of instruments from accordion to acoustic bass, the unobtrusive but beguilingly talented Dirk Powell provided delicate textures and characteristic solos, as well as his own American love song for piano and two voices.

This audience became a troupe of idealists, immersed in the warmth of Joan Baez’s love and profound humanity

Particularly memorable were his elaborate mandolin part on Nicaraguan song "Mi Venganza Personal" interwoven with Baez’s own intricate guitar-picking, a languid fiddle solo on "Long Black Veil" and his joyous energy on hillbilly tune "Cornbread". Having musically transported the ensemble to a mountaintop barn, he abandoned the banjo and took Baez’s arm for a lovely, if slightly unspontaneous, dance around the centre stage, while Baez’s son and percussionist Gabriel Harris took a cajon and djembe solo.

Sharing the bow with modest and tender guest vocalist Grace Stumberg as well as a girl introduced as Emma who continuously trotted on and off stage to tune and replace Baez’s guitar, there was a sense of the collective, on stage as much as off. And as Baez shared her first encore with the audience - a gentle singalong of John Lennon’s "Imagine" - pre-empting lyrics with little spoken cues, the true depth of her politics could be felt. Even such a popularised song was reborn and this seated audience became a troupe of idealists, immersed in the warmth of Joan Baez’s love and profound humanity.