As a child in Bombay, she was highly impressed by the music on her father's Western classical music records, particularly, she recalls, those of Maria Callas and Victoria de los Angeles. She learned light classical and popular songs and performed them socially and as a hobby. However, there was also a competitive music and drama festival in which she participated. Every year she and her brothers worked up a new pop or classical song, and often won. Her parents allowed her to go to England for her education and study music before returning to India to settle down, a plan she accepted. However, she says, from the moment she arrived "it was like an adventure unfolding."
She attended the Guildhall School of Music and Drama where her teacher was Walter Grüner. Recognizing her talent, and realizing she had not had a large or systematic exposure to the classical literature, he allowed her to sit in on senior level classes. She began to win prizes in student competitions, earning her another year's scholarship at the Guildhall. By the time she graduated, she had won the Guildhall School's Gold Medal and the Maggie Teyte Prize. Grüner assured her parents that she had true potential as a professional singer, and convinced them to give her time to develop a career.
She began singing professionally in England. In addition to singing the standard recital repertory, she sang frequently in early music productions and took a strong interest in contemporary works. An early appearance was in Monteverdi's Il combattimento di Tancredi e Clorida at the English National Opera, and also appeared at the Aix-en-Provence and Wexford Festivals, and with Opera North and the Glyndebourne Touring Opera.
In 1991, she auditioned for a part in John Tavener's new opera Maria Egiziaca (Mary of Egypt). He recognized in her voice "a unique spiritual and primordial quality that I have never been able to find in another singer." The drawback was that she lacked (she thought) the bottom notes in the part, down to G under middle C, which Tavener required to be sung strongly. She found that working on the opera opened this range to her naturally and comfortably.
After that project, she worked regularly with Tavener. She performed his Eternity's Sunrise, Apocalypse, and We shall see Him as He is at the BBC Proms, the world premiere of his Vlepondas at Queen Elizabeth Hall, and Agraphon at London's Barbican Centre. She starred in his massive work Fall and Resurrection, recording it for Chandos, and her recording of Eternity's Sunrise and other works of Tavener's on Hyperion had pop-hit sales figures. She premiered in Opera North's production of Simon Holt's The Nightingale's to Blame, and Arvo Pärt composed Como Anhela le Cierva for her.
She has recorded many of the works already mentioned, in addition to Haydn's Stabat Mater, Canteloube's Songs of the Auvergne, Britten's The Rape of Lucretia, songs of Severac, Tavener's Svyati, several CDs in Graham Johnson's great complete Schubert song series on Hyperion, Handel's Almira, and the Gramophone Award-winning recording of John Casken's opera Golem. In 2001, she was honored with an OBE, and in 2011 she and her husband began Giving Voice to India, teaching western classical vocal music to Indian students. The organization produced Purcell's Dido and Aeneas with an all-Indian cast in 2014.