The voice of the soprano Sarah Leonard, who has died aged 71 from a brain tumour, was familiar to aficionados of contemporary music for its ability to negotiate the stratospheric territory of the most taxing scores. It became known to a much wider audience through two particular recordings.

The first was Michael Nyman’s Memorial, premiered in 1985 to commemorate the deaths of 39 football fans at that year’s European Cup final between Liverpool and Juventus at the Heysel Stadium, Brussels. Above the Nyman Band’s pounding, funereal beat, Leonard was required to voice a long series of notes, many of them an octave above the stave. The bizarre, gut-wrenching result acquired cult status when it became part of the soundtrack of Peter Greenaway’s film The Cook, the Thief, His Wife & Her Lover (1989). The second recording was of part of John Harle’s Silencium (2011), used as the theme tune for the BBC crime drama series Silent Witness, in which the voice repeatedly intones an ethereal chant-like melody rising to a top A.

Leonard’s remarkable high register, combined with a reliable technique honed in a five-year stint with the BBC Singers (1976–81), ensured that she was much in demand with contemporary composers wishing to exploit the upper reaches of the vocal compass. Pascal Dusapin, Jonathan Harvey, Harrison Birtwistle and Joe Cutler were among leading composers of whose work she gave the premiere.

Helmut Lachenmann’s Got Lost, subtitled “Sarah’s Song”, premiered at the Munich Biennale for New Music Theatre in 2008, was written at her request, following her participation in his opera The Little Match Girl. Got Lost, for soprano and piano, incorporates – according to the score – “plosives, palatal clicks, cheek-patting slaps”, not to mention exaggerated exhalations, sighs, groans and whispers. Leonard took this kind of thing in her stride, as she did the absurdist theatricality of György Ligeti’s Aventures and Nouvelle Aventures, with their erotic grunts and eerie silences – the composer described these works as adopting five basic emotional registers “ranging from aggressive desire to terror”. She gave more than 30 performances of one score or the other.

She made her debut at La Scala, Milan, in the world premiere of Giacomo Manzoni’s opera Dr Faustus, in a staging by Robert Wilson (1989), and also appeared in Luigi Nono’s Al Gran Sole Carico d’Amore at the Hamburg State Opera (1999). She toured regularly with the Hilliard Ensemble, singing and recording the music of Arvo Pärt, among others, and also sang with the Michael Nyman Band for more than 15 years.

She made more than 35 CD recordings, including a recital series of English song with Malcolm Martineau, a song cycle also for voice and piano by Cutler, In Praise of Dreams, with her regular collaborator Stephen Gutman, and works by Edgard Varèse with Riccardo Chailly and the Concertgebouw Orchestra.

Born in Winchester, she was the daughter of Marjorie (nee Lait) and Kingsley Leonard. Her musical education began with lessons on the violin and piano, from the ages of eight and nine respectively, but her interest in contemporary music was largely inspired by her teacher Gillian Butterworth at the Winchester School of Art (1969–71). She went on to take a diploma at the Guildhall School of Music and Drama (1971-76), studying with Benjamin Luxon and Noelle Barker. In addition to her work with the BBC Singers, she sang with London Sinfonietta Voices and made broadcasts with the Endymion Ensemble and the London Sinfonietta. She sang Queen Elizabeth in the premiere of John Harle’s Angel Magick, on the subject of the Elizabethan occultist Dr Dee, at the BBC Proms in 1998, under the composer’s baton, in a production by David Pountney.

In the latter part of her career she taught on the BA acting (musical theatre) course at Royal Central School of Speech and Drama, and hosted popular residential courses at Benslow Music in Hertfordshire and Jackdaws in Somerset, appearing also at the annual summer festival at Benslow with Gutman. She additionally ran courses for choral singers at Morley College, London, and workshops for CoMA (Contemporary Music for All).

In 2013 she was awarded an honorary doctorate by Hull University for her services to music and in 2015 was elected chair of the Association of English Singers and Speakers.

She was married first, in 1975, to Michael Parkinson, a BBC colleague (though not the talkshow host), with whom she had a son, Edward, and a daughter, Helen; the marriage ended in divorce. In 2011 she married Peter Kelly, an IT consultant, who survives her, along with her children.

• Sarah Jane Leonard, soprano, born 10 April 1953; died 31 October 2024