After my dyspeptic middle-aged rant last month about the hegemony of pop music and its teenage values (Disgusted of Tunbridge Wells my wife called it, but I stand by every word), it was nice to perform Don Giovanni to a Royal Opera House full of children and teenagers a few Thursdays ago, and to find it the most enlivening and inspiring experience. Instead of the normal general rehearsal in the morning - more or less thickly populated by relatives, friends of the house and so on - we played to a seething, cheering, booing, gobsmacked crowd of schoolchildren from 68 different schools who filled the red-plush house to its rafters. Or so it seemed to me. That they should be amazed by the display of sophisticated pyrotechnics which Francesco Zambello's production conjures up for Don Giovanni's descent into hell was hardly surprising.