Danny42
But then, I recall going into a hardware shop once with careful measurements in mm for a tap adaptor. Chap in brown dust coat looked at this scornfully. "Drei vertel zoll " ("3/4 in"), he said, and reached down the bit I wanted fom the shelf. Seems imperial measures alive and well there in 1960,
Still alive and well in the 21st century.
British_Standard_Pipe