Ever since Roberto Alagna walked off the stage of La Scala mid-aria last December, he’s been trying to explain his side of things. His side does not include a great deal of contrition. “It was everyone else’s fault, apparently. He blames the conductor Riccardo Chailly for not holding the right tempo and the orchestra for playing ‘so-so’. The director, Franco Zeffirelli, he says, is ‘a great artist but not a great man… I left the stage because I was not well. I had hypoglycaemia. . When I have pressure I lose my sugar. I have a problem with my metabolism.”