Mary Hampton could not be accused of underthinking her current mini-tour. The Secret Gardens and Enchanted Follies odyssey, in support of her second album, Folly, takes in a slew of exotic venues including a tower in Lancashire and the yew garden of a Tudor house in Warwickshire. Tonight's show, the inaugural concert in the roof garden of the Queen Elizabeth Hall, is billed as taking place beneath a lunar eclipse.

The British summer intervenes, however, with a leaden, cloud-filled sky obscuring any hint of the spectacle, but it is clear nevertheless that Hampton is a rare talent. Backed by her string-heavy four-piece band Cotillion, the Brighton singer works firmly inside the folk tradition, but operates with an inventiveness that makes her mostly self-penned material sound refreshingly original.

Her most potent weapon is a keening, haunting vocal that burns like a laser through her sparse songs. Neither the chatter wafting up from the South Bank nor the clanking trains pulling into Charing Cross can distract from the eerie intensity of The Man Behind the Rhododendron, with its surrealist lyric of merry lords of England who "slept in caves, ate chandeliers", while the delicate, June Tabor-like Lullaby for the Beleaguered resonates with a rare and tender beauty.

Hampton is capable of incisive interpretations of traditional airs, as she proves when pulled back for an a cappella second encore of the ancient standard Three Maidens A-Milking Did Go. On this evidence, it would be foolish to bet against her reaching beyond niche audiences to more mainstream acclaim.