In 1952, he made his London debut at Wigmore Hall in London, conducted his own Leppard Ensemble.[2] He became closely associated with the Goldsbrough Orchestra, which became the English Chamber Orchestra in 1960.[2] Also, he gave recitals as harpsichordist, and was a fellow of Trinity College and a lecturer in music from 1958 to 1968. He retired from his post as Director of Music at Trinity College in 1968.[3]
His interest in early music prompted him to prepare several realisations of scores from the period. While musicologists considered his editions controversial, his performances were important for introducing early operatic masterpieces to the general public. In 1962, he prepared a performing score of Monteverdi's L'incoronazione di Poppea for a production at the Glyndebourne Festival.[3] He subsequently edited Monteverdi's other surviving stage works, L'Orfeo and Il ritorno d'Ulisse in patria, as well as operas by Francesco Cavalli and Jean-Philippe Rameau.[2][4] He conducted several of his realisations both in the theatre and in the recording studio.[4]
In September 1986 Raymond Leppard conducted the BBC Symphony Orchestra, Singers and Chorus at the Last Night of the Proms in the Royal Albert Hall, London.
In 1973, the Republic of Italy conferred upon him the title of Commendatore della Republica Italiana for services to Italian music. He received an Honorary Degree of a Doctor of Letters by the University of Bath in 1973.[6] He was appointed a Commander of the Order of the British Empire (CBE) by Queen Elizabeth II in 1983.[2] Leppard became an American citizen in 2003.[3] He died in Indianapolis on 22 October 2019.[2][1] He bequeathed his extensive archive of opera realisations to the Royal Conservatoire of Scotland.
Leppard received a total of 7 Grammy Award nominations during his career: