As from the Manchester conference hall I watched Theresa May’s big moment falling apart, as I buried my head in my hands while her agonies multiplied, I suppose I thought this could spell the end for her premiership. But even as I thought that, then reminded myself that the same failure of the larynx has afflicted me in front of a big audience and could strike anyone and is in itself meaningless, I knew such an outcome would be unjust.