=====Compromise?===== 
 I've done a lot of reading about all this now and read all your comments. I am happy to include words to the effect that verbal irony does not just mean the saying of the opposite to what you mean - in addition to the authorities that say it is. The reader should be allowed to make up their own mind. But we need citations. In the spirit of this compromise I would like to suggest this: From A glossary of literary terms, Abrams and Hartman.Verbal irony is a statement in which the meaning that a speaker employs is sharply different from the meaning that is ostensibly expressed. The ironic statement usually involves the explicit expression of one attitude or evaluation, but with indications in the overall speech-situation that the speaker intends a very different, and often opposite, attitude or evaluation. I do not, however, accept that sarcasm is ONLY expressed by irony.