‘It has become something of a King Charles’ head, or should that be a King Charles’s head?’ said my husband, laughing, as though he had made a joke. By ‘it’ he meant the apostrophe, which forces its way into any discussion of grammar, just as the head of the King and Martyr forced itself into the memorandum that Mr Dick, the amiable lunatic, was attempting to write to the Lord Chancellor in David Copperfield (1850).