The English soprano, Sheila Armstrong, was educated at the Royal Academy of Music in London, winning the 1965 Kathleen Ferrier Memorial Scholarship.
Sheila Armstrong made her operatic debut as Despina at the Sadler's Wells Theatre in London in 1965. Then sang at the Glyndebourne Festival from 1966 and at the Royal Opera House, Covent Garden in London from 1973. She primarily made her name in her own country, but mainly with work by Italians. Her specialties were Rossini and Donizetti, as well as Mozart. She was more versatile than that, though, within a particular stylistic range. She found success in Purcell's Dido and Aeneas (in which she made her Glyndebourne Festival debut in 1966) and L.v. Beethoven's Fidelio (her Covent Garden debut in 1973), and recorded English music, especially that of Ralph Vaughan Williams and Benjamin Britten.
Sheila Armstrong was also active as an oratorio singer, and toured Europe, North America, and Asia as a concert singer.
Sheila Armstrong retired from performances in 1993 at the fairly early age of 51. Unfortunately, technical concerns sabotaged her farewell. At a televised concert marking the 900th anniversary of the founding of Durham Cathedral, the TV crew prohibited the use of microphones for amplification in the cathedral, claiming that they would block the cameras' sight lines. As a result, many members of the audience couldn't hear Armstrong clearly, and walked out in frustration.