I need year at least and please describe the circumstances.
Mine was 2013. Some of my son's friends had been laughing about Boris Johnson, what a funny, funny Mayor of London; my son told them that he believed Boris was a dangerous lunatic. Later he relayed this story to me. I concurred and then said "You watch, that fucker will be running the country at some point".
I imagine many of you astute P&P'ers realised it even longer ago. Do tell.