Sir: I have always assumed 'nail' (Diary, 10 August; Letters, 17 August) to be a cont- raction of the acronym 'Naafi' from world war two. Anything supplied by that organ- isation was traditionally viewed as of in- ferior quality. Hence, for example, a stu- pid person was 'dim as a Naafi candle', etc.
M. S. Moss
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