 In 2000, Oxford University Press published a scholarly edition of the score and libretto, edited by Sullivan scholar David Russell Hulme.This restores the work as far as possible to the state in which its authors left it and includes a substantial introduction that explains many of the changes, with appendices containing some music deleted early in the run.After the expiration of the British copyright on Gilbert and Sullivan works in 1961, and especially since the Sadler's Wells production and recording, various directors have experimented with restoring some or all of the cut material in place of the 1920s D'Oyly Carte version.