Smith has endured a storm of criticism since ENO artistic director Sešn Doran resigned last month and was quickly replaced from within. The change of leadership came just two years after Smith forced out general director Nicholas Payne, a move also widely condemned in the arts community.

"Mr. Smith's style of chairmanship, we believe, has been most damaging to this important institution and has brought about a crisis point," the letter reads in part. "Sadly, the very survival of ENO is now openly questioned and an urgent change in leadership is necessary to ensure a better future."

The release of the letter today coincides with a gala performance of Anthony Minghella's production of Madama Butterfly, with Prince Charles and his wife, the Duchess of Cornwall, in attendance.