Have you heard this expression before?
The English teacher at my school asked me to explain this to his class as when he googled it it said it was a British expression. So as I'm the only brit it fell to me to explain.
Have I lived under a rock for the last 50 years as I didn't have the foggiest. I asked DH when I got home and he knew it. But he's weird so that's not a fair test of how well known it is.
Do you know what it means? I wouldn't want this class of foreigners thinking we're all going round spouting stuff like this if you're all as clueless as I was.