Had to rush out to fetch daughter from drama school.Now I have been thinking about the case, and I can't be sure, but it was either a very famous lawyer - not recent like FE Smith but sort of Blackstone-ish period, or perhpas DR Johnson. It was something to do with a hypothetical question of some sort, and he was than asked a "what if", and that waw the reply.
But my favourite road signs must be place names: -
Pratt's Bottom
Piddlehinton (and the RIver Piddle)
And Penistone