The three note that within a day of Doran's departure last week, the ENO appointed Loretta Tomasi, previously the company's executive director, as chief executive and elevated director of opera programming John Berry to artistic director.

"We ask that the chairman and board of ENO answer as a matter of urgency questions concerning their actions in choosing not to advertise these positions," they write. "The stability of ENO after its recent vicissitudes is a matter of public concern of all those who have its interest at heart."

Martin Smith, the chairman of the ENO, defended the company in a statement.

"[T]he board faced a choice," he said. "It could either enter into an extended period of uncertainty and speculation surrounding these jobs, or confirm in post two individuals with proven artistic and managerial records who were already carrying out many of these responsibilities with full board confidence. It concluded that the latter course was in the best interests of the company."

Smith also condemned press reports suggesting that the ENO was in turmoil, pointing out that attendance is rising and that the company recently extended its sponsorship deal with the satellite broadcaster Sky and Artsworld.