Is this a stanard medical phrase (for eating & drinking nothing before a surgical operation)? I'm not familiar with it, and as far as I can see it is hardly findable in dictionaries or even Google!
Thank you all: that was quick! I'm only used to the French & German expressions, which are even shorter ("à jeune" & "nuechtern"). Perhaps not necessarily desirable to have lain in British hospitals for 50 years: the experience is bad enough anywhere!
First time I saw it , it was over a garden shed. The wife was a nurse, and I suspect the husband used to retreat to the shed for a quiet smoke and a drink !